RP-7-01 ERRATA

If you, as a user of IESNA’s Recommended Practice for Industrial Lighting Facilities, believe you have
located an error not covered by the following revisions, you should e-mail your information to Don
Mennie at: dmennie@iesna.org or send a letter to: Don Mennie, Technical Editor, IESNA, 120 Wall
Street 17th Floor, New York, N Y 10005. Additions will be posted to this list as they become available.
This errata list is also included with the published document (when purchased). It was posted to the
IESNA web page on July 20,2004.

Please confiie your comments to specific typographical errors or misstatements of fact in the docu-
ment’s text and/or graphics. Do not attempt general revisions of RP-7-0 1.

General Comment: Rest assured that IESNA does know how to spell “luminaires,” but unfortunately,
thanks to a typesetting automatic correction function, the computer thought it knew better! Please note
that “luminaries” throughout the document should read “luminaires.”

Page I I , Figure 6: The headers for the three CIE Specification columns in Figure 6 should read “x,”
and <<y??
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Pages 34-36, Figure 20: The references within Figure 20 to a Figure 19 (parts “a” through “o”)
actually refer to Figure 19-15 in the IESNA Lighting Handbook, 9th Edition. (Figure 19 in RP-7-01 is
a small black-and-white photo on Page 33.) Also, the “Luminaire Type” designations used in one col-
umn running throughout Figure 20 are taken from Figure 19-15. Therefore, in the interests of conven-
ience and completeness, Figure 19-15 (from the Handbook) is reproduced below:

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 Lo o o O ] s-IV
9

Figure 19-15. Typical configurations of supplementary lighting luminaire types.

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 Page 36, Figure 20: Under ?B. TRANSLUCENT MATERIAL? two of the figure references in the
right-hand ?Luminaire Location? column are broken, with a portion positioned flush left in the
?General Characteristics?co1umn.

Page 71, Annex C: The equations for FCR and CCR appearing at the top of the left-hand column
actually belong on page 72 in the left-hand column, under the second paragraph.

Page 71, Annex C: Text and equations are missing from the bottom of the left-hand column (this
error continues to the very top of the right-hand column) in the paragraph that begins ?TO find the
RCR,. ..?The complete and correct text is:

To find the RCR, either of the following equations can be used:

Vertical Surface Area (VSA)
RCR = 5X
Horizontal Surface Area (HSA)
where:
VSA = the sum of the vertical surfaces within the room cavity. This is the sum of the wall areas
above the working plane and below the luminaires.

HAS = the sum of the working plane and the luminaire plane areas.

or:
Room Cavity Height X (Lenght + Width)
RCR =5X
Length X Width

Correct text resumes on page 71 with the beginning of the first full paragraph in the right-hand column
(?The areas in the first equation are.. ..?).

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 ERRATA RP-7-01
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1. Rest assured that IESNA does know how to spell “luiiiinaires,” bui unfortunately,
thanks to a typesetting automatic correction function, the computer thought it
knew better! Please note that “luminaries” throughout the document should read
“luminaires.”

2. Header for Figure 6, page 1 1, CIE Specification columns should read “x,” “y,”
and “Y”

3. Figure 20, pages 34 -26, is reproduced from the IESNA Handbook, 9‘h Edition,
2000. The references to Figures (some misaligned) throughout are to Figures in
the Handbook.

4 . Annex C has some misplaced equations. On page 7 I , left columnl equations foi-
I’CR and CCR belong on pase 72 following the second paragraph. left column.

h4issing annescs on page 7 1. left coliiii~ii.Test should i-ead:

P’ei~icuISin:fcrce Ar-eu (J’SA)

RCR = 5.y
Horizoritul Surjuce Areu ( H S A )

where:
VSA = the s u m of the vertical surfaces within the room cavity. This is the sum
of the wall areas above the working plane and below the luminaires.

HSA = the sum of the working plane and the luminaire plane areas

Or:

Room Cavity Height x (Length + Width)

RCR = 5x
Length x Width

The areas in the first equation.. .......etc. Right column, page 7 1.

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 ANSUIESNA RP-7-01

Recommended Practice
for
Lighting Industrial Facilities

Publication of this Committee

Report has been approved
by the IESNA. Suggestions for
revisions should be directed
to the IESNA.

Prepared by:
The IESNA Industrial Lighting Committee

Cover photo courtesy of Keene-WideliteDivision of Canlyte

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 ANSI / IESNA RP-7-01

Copyright 200 7 by the Illuminating Engineering Society of North America.

Approved by the IESNA Board of Directors, August 4, 2007,as a Transaction of the Illuminating Engineering
Society of North America.

Approved July 26, 2001 by the American National Standards Institute, Inc.

All rights reserved. No part of this publication may be reproduced in any form, in any electronic retrieval system
or otherwise, without prior written permission of the IESNA.

Published by the Illuminating EngineeringSociety of North America, 120 Wall Street, New York, New York 10005.

IESNA Standards and Guides are developed through committee consensus and produced by the IESNA Office
in New York. Careful attention is given to style and accuracy. If any errors are noted in this document, please for-
ward them to Rita Harrold, Director Educationaland Technical Development, at the above address for verification
and correction. The IESNA welcomes and urges feedback and comments.

ISBN #O-87995-176-1

Printed in the United States of America.

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 ANSI / IESNA RP-7-01

ANSMESNA RP-7-01 Recommended Practice on Industrial Lighting

Prepared by the IESNA Industrial Lighting Committee

RP Task Force:
Diarmuid McSweeney, FIES Chair

C. Amick
D. DeGrazio
R. Knott
S. Mishky
D. Paulin
M. Rhodes
G. Schaefer

Industrial Lighting Committee

William Busch, Chair 7994-99
Diarmuid McSweeney, FIES Chair 2000 -

C. Amick, FIES R. Knott*

P. Belding W. Lane*
W. Busch P. Lanphere*
K. Chen* S. Mishky
D. DeGrazio M. Packer*
F. Dickey D. Paulin
D. Duzyk* M. Rhodes
J. Engle* G. Schaefer
J. Fetters* W. Smelser*
D. Finch S. Thomas
J. Fischer R. Topalova
J. Huebner J. Vlah*
G. Imine* R. Weber*
V. Jones

*Advisory
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Special recognition to F, Dickey for his work on the first draft of the revision of this
standard and to P. Boyce, FIES and R. Mistrick, FIES for their contributions.

DEDICATION

The IESNA Industrial lighting Committee

would like it noted that Charles Amick
contributed greatly to the development of this
document. The committee, therefore,
dedicates this recommended practice to
the late Charles Amick.

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CONTENTS

Forward ..................................................................................................................................................................... 1

1.0 INTRODUCTION.............................................................................................................................................. 1

2.0 LIGHTING THE INDUSTRIAL ENVIRONMENT ............................................................................................ 1

2.1 General Design Considerations for Lighting Industrial Areas ..................................................... 1
2.2 IESNA Lighting Design Guide .......................................................................................................... 2

3.0 QUALITY OF LIGHTING IN INDUSTRIAL FACILITIES................................................................................ 2

3.1 Luminance and Luminance Ratios ................................................................................................... 2
3.2 Modeling of Objects ............................................................................................................................ 6
3.3 Glare and Visual Discomfort ............................................................................................................ 6
3.4 Material Characteristics...................................................................................................................... 7
3.5 Shadows ............................................................................................................................................... 8
3.6 SourcNasWEye Geometry................................................................................................................ 8
3.7 Task Visibility-Flicker and Strobe .................................................................................................... 9
3.8 Color Rendering (CRI) ...................................................................................................................... 10
3.8.1 Color Rendering Index .......................................................................................................... 10
3.8.2 Safety Colors......................................................................................................................... 10
3.9 Daylight Integration and Control..................................................................................................... 10

4.0 QUANTITY OF LIGHTING IN INDUSTRIAL FACILITIES ........................................................................... 11

-
4.1 Illuminance Horizontal, Vertical and Intermediate Planes........................................................ 11
4.1.1 Horizontal Illuminance........................................................................................................... 11
4.1.2 Vertical Illuminance............................................................................................................... 12
4.2 Initial and Maintained Illuminance .................................................................................................. 12
4.3 Lighting System Maintenance......................................................................................................... 13

5.0 GENERAL LIGHTING EQUIPMENT ............................................................................................................ 13

5.1 Fluorescent Systems ........................................................................................................................ 13
5.1.1 Source Characteristics.......................................................................................................... 13
5.1.2 Fluorescent Luminaire Characteristics/Performance........................................................... 15
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5.2 High Intensity Discharge Lighting Systems .................................................................................. 15

5.2.1 Metal Halide Lamps .............................................................................................................. 15
5.2.1.1 Pulse-Start and Ceramic Metal-Halide Lamps ................................................ 17
5.2.2 High Pressure Sodium (HPS) Lamps ................................................................................. 17
5.2.3 Luminaire Selection .............................................................................................................. 17
5.2.3.1 High-Bay Luminaries ......................................................................................... 18
5.2.3.2 Low-Bay Luminaries.......................................................................................... 18
5.2.3.3 Other Luminaire Types ..................................................................................... 18

6.0 BALLAST ISSUES-GENERAL..................................................................................................................... 18

6.1 Fluorescent Ballast Issues ............................................................................................................. 19
6.1.1 Ballast Circuitry........................................................................................... .......................... 19
6.1.2 Electromagnetic Ballasts....................................................................................................... 20
6.1.3 Electronic Ballasts................................................................................................................. 20
6.1.4 Instant Start Ballasts ............................................................................................................. 20
6.1.5 Rapid Start Ballasts ............................................................................................................. 21
6.1.6 Compact Fluorescent Ballasts.............................................................................................. 21
6.1.7 Dimming and Two-Level Switching Ballasts ........................................................................ 21
6.1.8 General Ballast Requirements.............................................................................................. 21
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6.2 High Intensity Discharge (HID) Ballast Issues .............................................................................. 21

6.2.1 Ignitor..................................................................................................................................... 23
6.2.2 Metal-Halide Ballasts ........................................................................................................... 23
6.2.3 High Pressure Sodium Ballasts............................................................................................ 23
6.2.3.1 Magnetic Regulator or Constant-Wattage Autotransformer (CWA) Ballast..... 23
6.2.3.2 Lag or Reactor Ballast ....................................................................................... 23
6.2.3.3 Lead Circuit Ballast............................................................................................ 24
6.2.4 Other HID Ballasts ................................................................................................................ 24

7.0 DISTRIBUTION MODES................................................................................................................................ 24

7.1 General Luminaire Characteristics and Performance ................................................................ 24
7.2 Operating Considerations ................................................................................................................ 24
7.2.1 Electrical ................................................................................................................................ 24
7.3 Luminaire Classifications ............................................................................................................... 24

8.0 BUILDING CONSTRUCTION FEATURES THAT INFLUENCE

LUMINAIRE SELECTION AND LUMINAIRE PLACEMENT ........................................................... 26

9.0 LIGHTING SYSTEM ECONOMIC ANALYSIS ............................................................................................. 27

10.0 SPECIAL CONSIDERATION FACTORS...................................................................................................... 29

10.1 Lighting and Space Conditioning ................................................................................................... 29
10.2 Classified Areas ................................................................................................................................ 29
10.3 High Humidity or Corrosive Atmospheres .................................................................................... 30
10.4 High Ambient Temperatures............................................................................................................ 30
10.5 Low Ambient Temperatures............................................................................................................. 30
10.6 Clean Rooms ..................................................................................................................................... 30
10.7 Food and Drug Processing.............................................................................................................. 31

11.o GENERAL LIGHTING ................................................................................................................................... 31

12.0 SUPPLEMENTARY TASK LIGHTING.......................................................................................................... 31

12.1 Luminaries for Supplementary Task Lighting ............................................................................. 32
.l 2.2 Portable Luminaries ......................................................................................................................... 32
12.3 Classification of Visual Tasks and Lighting Techniques............................................................. 33

13.0 SPECIAL EFFECTS AND TECHNIQUES ................................................................................................... 33

13.1 Color Contrast .................................................................................................................................. 33
13.2 Inspection Techniques .................................................................................................................... 33

14.0 EMERGENCY. SAFETY AND SECURITY LIGHTING ............................................................................... 36

14.1 Emergency Lighting ........................................................................................................................ 36
14.2 Safety Lighting ................................................................................................................................. 37
14.3 Security Lighting .......................................................... :.................................................................... 37

15.0 LIGHTING FOR SPECIFIC TASKS .............................................................................................................. 37

15.1 Molding of Metal and Plastic Parts: Discussion of Lighting and Equipment Choices .......... 38
15.1.1 Foundry Molding (Sand Casting).......................................................................................... 38
15.1.2 Molding Parts of Die-Cast Aluminum and Injection Molded Plastic .................................... 38
15.1.3 Inspection of Sand Castings................................................................................................. 38
15.1.4 Inspection of Die-Castings and Opaque Injection Molded Plastic Parts............................. 39
15.2 Parts Manufacturing and Assembly ............................................................................................... 39
15.3 Machining Metal Parts ...................................................................................................................... 40

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16.0 LIGHTING FOR SPECIFIC VISUAL TASKS .............................................................................................. 40

16.1 Convex Surfaces ............................................................................................................................... 40
16.2 Flat Surfaces ...................................................................................................................................... 40
16.3 Scribed Marks .................................................................................................................................... 40
16.4 Center-Punch Marks ......................................................................................................................... 41
16.5 Concave Specular Surfaces ........................................................................................................... 41
16.6 Flat Specular Surfaces ..................................................................................................................... 41
16.7 Convex Specular Surfaces ............................................................................................................. 41
16.8 Lighting and Visibility for Specific Sheet Metal Fabrication ...................................................... 42
16.8.1 Punch Press ......................................................................................................................... 42
16.8.2 Shear ..................................................................................................................................... 42
16.9 Lighting for Large Component Sub- and Final Assembly .......................................................... 42
16.10 Control Rooms ................................................................................................................................. 43
16.11 Warehouse and Storage Area Lighting.......................................................................................... 44
16.11.1 Types of Warehouse Area and Storage Systems............................................................... 44
16.11.2 Warehouse Illuminance ...................................................................................................... 44
16.11.3 Warehouse Lighting Design Considerations ...................................................................... 45

17.0 OUTDOOR AREA LIGHTING ....................................................................................................................... 46

17.1 Projected Lighting Systems ........................................................................................................... 46
17.2 Distributed Lighting Systems ......................................................................................................... 46
17.3 Outdoor Tower Platforms, Stairways and Ladders ...................................................................... 46
17.4 Special Equipment ............................................................................................................................ 47
17.5 Low Illuminance and Visual Acuity Outdoors .............................................................................. 47

References .............................................................................................................................................................. 47

Annex A l
The Basis for Deviating from Recommended Illuminances .................................................................. 48

Annex A2
Recommended Illuminance Values (target maintained) for Industrial Lighting Design ................... 51

Annex B
Predictive Methods for Determining Visual Comfort Probability (VCP)
and Unified Glare Rating (UGR) ................................................................................................................ 64

Annex C
Average Illuminance Calculation: The Lumen Method ......................................................................... 69

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 ANSI / IESNA RP-7-01

FOREWORD warm-up periods or stroboscopic effects created

(This Foreword is not part of the American National where rotating paris are present. The ability of the
Standard and Practice ANSIAESNA RP-7-01.) lamps to render colors accurately may have an effect
on the recognition of colors or product components
While the objectives of this Recommended Practice and safety colors used to protect the workers from
are to give a comprehensive treatment of lighting in the dangerous conditions within the work place. Many
industrial environment, there are many spaces in a industrial operations take place in hostile environ-
modern industrial complex that are used for purposes ments, and the hardware used in these locations
other than manufacturing. These include offices, meet- must be designed and manufacturedto survive these
ing, conference and reference spaces. It is suggested conditions. For these reasons, and many others,
that the reader refer to the most recent version of these great care is requiredto provide an effective, efficient
other IESNA Recommended Practices and Design and readily maintainable lighting system to help mod-
Guides for the appropriate lighting recommendations ern industrial workers produce at the peak of their
for spaces not covered in this publication: ability in a safe environment.

ANSMESNA RP-1, Recommended Practice on

Office Lighting 2.0 LIGHTING THE INDUSTRIAL ENVIRONMENT
IESNA RP-5, Recommended Practice of
Daylighting
IESNA RP-20, Recommended Practice on Lighting Providing a successful lighting design for a modern
for Parking Facilities industrial facility is a complex task. In the last three
ANSI/NECA/IESNA 502, Recornmended Practice decades of the 20th century, much has been leamed
for Installing Industrial Lighting Systems about lighting and its positive effects on the well being of
IESNA DG-2, Design Guide for Warehouse people. The goal of providing an efficient, reliable and
Lighting easily maintainable lighting system, making use of all of
the knowledge available to the designer today, is a task
that requires experience and considerable planning.
1.O INTRODUCTION
2.1 General Design Considerations for Lighting
Industrial Areas
A well-designed lighting system can make an impor-
tant contribution to the success of an industrial facility. The designer of an industrial lighting system should
Unfortunately, too often the lighting is treated as an carefully consider all of the following design criteria
afterthought during the planning and construction of since any single issue, or combination of several,
these facilities. Great attention is paid to the physical could be important in planning a successful industri-
dimensions of the building, to the flow of the process al lighting installation. (These criteria are not neces-
and materials, and to production equipment. sarily arranged in order of importance since priorities
will vary for different industries or different locations
It is common that only horizontal illuminance is con- within an industrial complex.)
sidered in providing an environment in which to per-
form industrial tasks. However, many industrial tasks 1. Determine the quality of illumination for the manu-
do not occur in a horizontal plane. There are many facturing processes involved. (See the Industrial
features of the lighting system, other than quantity of Lighting Design Guide in Figure 1 (a) and Section
light, which make a significant contribution to the effi- 3.0.)
ciency of the industrialworker. Placement of the lumi- 2. Determine the quantity of illuminationfor the manu-
naries is critical to providing light of the proper quali- facturing processes involved. (See the Industrial
ty, as well as quantity and direction, to allow fast, Lighting Design Guide in Figure 1 (a) and (b),
easy recognition of operations, which may be taking Section 4.0 and Annex C.)
place at high speeds in portions of production 3. Determine the lighting required for safety and
machinery where ambient light cannot easily pene- ensure all three conditions (quality, quantity and
trate. Selection of the luminaire distribution can be safety) are properly weighed and addressed in the
important to rendering the visual task properly when final design.
that task is multi-dimensional rather than flat, and 4. Select listed or approved lighting equipment that
when the task occurs in a plane other than horizon- will provide the requirements of quality and quan-
tal. The operation of the light sources must be under- tity, including photometric characteristics, as well
stood to ensure that the proper lamps are selected. as the mechanical performance required to meet
Improper light source choice can result in difficult and installation and operating conditions.
potentially dangerous conditions caused by long
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 ANSI / IESNA RP-7-01

practical to maintain. Evaluate Figure l(b) Determination of Illuminance Categories.

operating conditions that may cre-
ate dangerous or unacceptable
risks to people, plant or equipment.
6. Consider the energy, economic and
operating characteristics of the
selected lighting system and be
sure all factors have been proper- A Public Spaces 30 lx (3 fc)
ly weighed and balanced against B Simple orientation for short visits 50 lx (5 fc)
the five considerations above C Working spaces where simple visual tasks are 100 lx (10 fc)
before finally accepting the design. performed

2.2 The IESNA Lighting Design

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Guide and Industrial
Lighting Design Recommen-
dations
D Performance of visual tasks of high contrast and 300 ix (30 fc)
large size
In the past, the IESNA has always E Performanceof visual tasks of high contrast and 500 lx (50 fc)
recommended illuminances for specif- small size, or visual tasks of low contrast and
ic applications or visual tasks. Such large size
recommendations were often mistak- F Performance of visual tasks of low contrast and 1O00 lx (1 OOfc)
en as the primary or even sole criteri- small size
on for lighting design. Beginning with
the publication of the IESNA Lighting
Handbook, 9th Edition,’ the Society
has introduced a new, formal system
for considering a wide range of light-
ing design criteria important for a high- G Performance of visual tasks near threshold 3000-10,000 IX
quality visual environment. This new (300- 1 O00 fc)
system emphasizes quality factors as
well as illuminance. *
reflections, measured illuminance should be within 10 percent of the recommended
value. It should be noted, however, that the final illuminance may deviate from these rec-
ommended values due to other lighting design criteria.
Central to the new system is the
IESNA Lighting Design Guide. The
columns of the Design Guide list multiple criteria impor- Guide in Figure 1 (a). These include luminances of
tant for a high quality visual environment, while the room surfaces, modeling of objects, glare, shadows,
rows list specific locations and tasks alphabetically. At source/task/eye geometry, flicker and strobe, color
each row/column intersection,a shaded block indicates appearance and color contrast, and daylight integra-
the level of importance for each criterion as it relates to tion and control.
the associated location or task: very important = solid
shading; important = medium shading; somewhat 3.1 Luminance and Luminance Ratios
important = light shading; and not important or not
applicable = no shading (blank). Those portions of the The ability to see detail is strongly influenced by the
Design Guide that apply to industrial applications are contrast between the task detail and its background.
presented in Figure 1 (a), (page 9.) (See Chapter 1O in The greater the contrast, or difference in luminance,
the IESNA Lighting Handbook, 9th Edition, for the com- the more readily the task is seen. However, the eyes
plete Guide for all other applications.) function more comfortably and efficiently when the
luminances within the total visual environment are
fairly uniform. Therefore, all luminances in the field of
3.0 QUALITY OF LIGHTING IN INDUSTRIAL view should be carefully controlled. In manufacturing,
FACILITIES there are many areas where it is not practical to
achieve the desirable luminance relationships as
those more easily achieved in areas such as offices.
A pleasant and comfortable environment is desirable But between the extremes of heavy manufacturing
and will generally result in a happier and more pro- and office spaces lie the bulk of industrial areas.
ductive worker. There are various factors to consider Therefore, Figure 2 (see page 6 has been developed
in determining the quality of the visual environment. as a practical guide to recommended maximum lumi-
They appear in the column headers in the Design nance ratios for industrial areas.
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 ANSI / IESNA RP-7-01
Figure l(a). Lighting Design Guide for Industrial Diications.

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3
 ANSI / IESNA RP-7-01

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Figure 2. Recommended Maximum Luminance Ratios.

Environmental Classification”
A B C
1. Between tasks and adjacent darker surroundings 3 to 1 3 to 1 5 to 1
2. Between tasks and adjacent lighter surroundings 1 to3 1 to3 1 to 5
3. Between tasks and more remote darker surfaces 10 to 1 20 to 1 +
4. Between tasks and more remote lighter surfaces 1 to10 1 to20 +
5. Between luminaries (or windows, skylights, etc.) 20 to 1 + +
and surfaces adjacent to them
6. Anywhere within normal field of view 40 to1 + +
I
* Classifications are:
A- Interior areas where reflectances of space can be controlled in line with recommendationsfor optimum visual conditions.
B- Areas where reflectances of immediate work area can be controlled, but control of remote surround is limited.
C- Areas (indoor and outdoor) where it is completely impractical to control reflectances and difficult to alter environmental conditions.
+ Luminance ratio control not practical

Workers may experience eye adaptation changes in

shifting their gaze away from a task if the new princi- Surfaces Reflectance (%y
pal luminances in a changed viewing direction are sig- Ceiling 50% - 70%
nificantly different from those in the task surround. Walls 40% - 60%
This is sometimes called transient adaptation. In cer- Desk & Bench Tops, Machines
tain industrial operations, workers may experience & Equipment 25% - 45%
“transient adaptations” continuously during a normal Floors
- 20%
workday. Problems caused by luminance differences
‘Reflectance should be maintained as near as practical to recom-
in the environment can be reduced or avoided by pro- mended values
viding the recommended luminance ratios.
Figure 3. Recommended Reflectance Values
To achieve the recommended luminance relation- (Applying to Environmental ClassificationsA and 6
ships, it is necessary to carefully select the in Figure 2)
reflectance values of all room surface and equipment
finishes, as well as control the candela distribution of teristics of the lamps being used in the space must
the lighting equipment. Figure 3 lists the recom- also be considered. Failure to do this could produce
mended reflectance values for industrial interiors and a color appearance completely different from the one
equipment. High reflectance surfaces are generally anticipated. Paint samples should always be
desirable to provide the recommended luminance reviewed under samples of the actual lamps to be
relationships and maximize the utilization of light. installed to avoid annoying surprises after the project
They also improve the appearance of the workspace. is completed.
A large industrial room with dark surfaces can elicit a
“cave-like” sensation. At the same time, there may be 3.2 Modeling of Objects
visibility consequences from improper luminance
ratios for tasks located adjacent to dark walls or Lighting will reveal the depth, shape and texture of an
where the wall forms a significant part of the task object. In industrial applications, modeling of the visu-
background. If low-reflectance walls and ceilings al task can be critical to assessing quality of raw
exist, a major improvement in lighting system perfor- materials, quality of finished goods and degree of
mance can be achieved by refinishing those surfaces consistency in manufacturing processes. Appropriate
to the reflectances recommended in Figure 3. direction and distribution of light may vary depending
on material and task. Diffuse ambient lighting is often
In many industries, machines are painted to present a inadequate for assessing fine texture; task lighting
completely harmonious color environment. A slightly may be used to provide the required direction, distrib-
darker background than the task detail is usually pre- ution and intensity of light. (See Section 12.0,
ferred. Stationary and moving parts of machines Supplementary Task Lighting.)
should be finished with contrasting colors standard-
ized within the facility to reduce accident hazard. 3.3 Glare and Visual Comfort

When color combinations are selected for the build- Glare is the sensation produced by luminance within
ing and machinery parts, the color rendering charac-
--``````-`-`,,`,,`,`,,`---
the visual field that is sufficiently greater than that to
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which the eyes are adapted. Glare may cause annoy- Specific glare ratings for lighting in actual rooms may be
ance, discomfort or loss of visual performance and calculated using the methods described in Annex B.
visibility. Direct glare results from high luminances or
from unshielded light sources. Glare can be reduced Reflected glare can be minimized or eliminated by
by decreasing the luminance or area of the glare using light sources of low luminance or by orienting
source, by raising the glare sources further above the the work so that reflectionsare directed away from the
line of sight, and by boosting the ambient illuminance. normal sight line to the task. It is often desirable to use
large-area luminaries of low luminance located over
Reflected glare results from high luminance sources the work. See Section 12.0, Supplementary Task
or from luminous difference reflected from specular Lighting for possible solutions to such problems.
(shiny) surfaces. ?Veiling reflections? are contrast-
reducing reflections from semi-specular surfaces that Unshaded factory windows frequently contribute to
may reduce task visibility. glare sensations among production personnel attrib-
utable to a direct view of the sun, bright portions of the
Disability glare is caused by a veiling luminance sky or even light surfaces of adjacent buildings. Direct .
superimposed. on the retinal image within the eye, sunlight entering the work area may cause glare
which reduces visual performance or visibility, and is when reflected off interior surfaces.
often accompanied by discomfort. Reducing illumi-
nance at workers?eyes and/or raising the source of 3.4 Material Characteristics
the disability glare can alleviate the problem.
Lighting designers must pay attention to material
Discomfort glare produces visual discomfort without characteristics of visual tasks, such as texture, spec-
necessarily interfering with visual performance or vis- ularity, transparency and translucency. These provide
ibility. It occurs when luminous objects (or reflections visual cues and are often a functional part of task con-
of luminous objects) have significantly higher lumi- trast. They can also impact important process consid-
nance than the balance of the person?sfield of view. erations such as degree of finish or completeness,
Size, luminance and angular displacement from the material quality or correctness as well as other pro-
line of sight are all factors. Even a source that is duction issues. Modeling the principal tasks with a
directly overhead, if bright enough, can cause dis- test installation will help determine the optimum light-
comfort glare. ing system and geometry. Such a test should include
the actual task and a minimum of 4 luminaries at an
Individual tolerances vary, but visual evaluations of dis- appropriate mounting height and spacing.
comfort glare have resulted in numerical systems of
rating the discomfort glare, based on luminaire lumi-
nance, luminaire size, luminaire positions, room dimen-
sions, surface reflectances and average illuminance.

There are two methods used for predicting glare; an

empirical prediction system used in North America
called the Visual Comfort Probability (VCP) system,
and a Unified Glare Rating System (UGR) used pri-
marily in Europe. See Annex B for a discussion of
--``````-`-`,,`,,`,`,,`---
each. Note that VCP is used for direct distribution
fluorescent luminaries only.
Angle of Angle of Source
The glare sensation from an industrial system can be
reduced by decreasing the luminance of the light
sources or the luminance of the luminaries; for exam-
ple, choosing a luminaire with a larger refractor. So-
called ?high-bay?high intensity discharge (HID) sys-
tems, where luminaries are mounted 7.6 m (25 ft) or
more above the floor, are considered satisfactory with
respect to glare. High-bay luminaries, however, often
provide a variety of socket positions, which may place
lamps so low in the reflector that they have little or no Normal
cutoff. For such situations, luminaire accessories, Figure 4 (a). Angle of incidence equals angle of
such as louvers, may be considered. reflection.

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 ANSI / IESNA RP-7-01

Bright images reflected from computer screens are fre- 3.5 Shadows
quently the cause of veiling reflections. (See Figure 4
(b).) Screen reflections may be caused by overhead Shadows can interfere with task visibility by placing
luminaries, light colored clothing worn by employees, detail in darkness (e.g., a body shadow on a
and unshielded windows or skylights. Means of control machine task), or they can enhance definition of
include total cutoff of light source images, changing three-dimensional details (e.g., imperfections in tex-
VDT orientation and position, using better contrast tiles). Point sources (e.g., incandescent or high
screens, adding shields to the monitor, and blocking the intensity discharge lamps) create more defined
view of luminous surfaces in the offending zone. (See shadows than fluorescent lamps, which produce dif-
Figure 4 (c).) For more detailed information on lighting fuse shadows.
for VDT workstations see latest version of IESNA RP-
1, Recommended Practice on Ofice Lighting. Generally, a large area of shadow, covering the
whole task area, will simply lower the task illumi-
nance. Shadows cast by the structure of the task
may reveal detail, or may mask what needs to be
seen. High reflectance surroundings help fill in and
modify shadows, as do luminaries with 10 percent or
more uplight when the ceiling cavity reflectance is
over 50 percent. A combination of supplementary
task lighting and general illumination is often the
best approach, if care is taken to minimize glare.

The presence of shadows may be desirable, and the

interplay of highlight and shadow helps to define the
form of many visual tasks. Lighting vertical surfaces
to at least half the horizontal illuminance level often
Figure 4 (b). Veiling reflections in a VDT screen. brings the ratio of highlight to shadow into a tolera-
ble range for three-dimensional tasks. Some shad-
ow will still be present, which helps to model the task
and reveal form. Since each visual task has an opti-
mum range of modeling, a careful evaluation of crit-
ical visual tasks should be made to determine the

--``````-`-`,,`,,`,`,,`---
effects of various ratios of horizontal vs. vertical illu-
minance on visibility.

Obstructions below the luminaire mounting plane,

such as pipes and ducts, and the location and orien-
tation of the task, affect the availability of vertical illu-
minance. Obstructions can also produce shadows,
as can an operator positioned between the task and
the luminaries. When a task is close to a wall, and
the operator is facing the wall, relatively few lumi-
Figure 4 (c). Veiling reflections are minimized to naries are likely to contribute to task illuminance. In
enable the operator to clearly see the drawing on these cases, high wall reflectances (greater than 60
the screen. (Photo courtesy of Ruud Lighting.)
percent) can improve task visibility.

Veiling reflections also occur in manufacturing areas 3.6 SourceKasiúEye Geometry

of an industrial facility. For example, in the electronics
industry, solder used in the manufacture of printed cir- The angular relationships between the viewer, the
cuit boards has specular characteristics. Glare reflect- task and the luminaire are frequently critical to task
ed from the solder will hinder the ability of the worker visibility. Industrial tasks are often three-dimensional,
to see the detail of the circuitry on the board. and they often move. Because viewing angles are
dynamic, the source/task/eye geometric relationships
Not all specular reflections on tasks reduce visibility. must be understood for individual work areas. The
Incised markings on micrometers and other calibrating geometry can enhance contrast (e.g., scribed marks
instruments are more easily seen when the angle of the on a micrometer) or reduce it (e.g., viewing a meter
light source creates a bright edge against a shadow to dial through glass).
enhance the detail of the task. (See Section 16.1.)
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3.7 Task Visibility - Flicker and Strobe inated when operated at high frequency on electronic
ballasts. Sensitivity to flicker varies among individuals,
Flicker is the rapid variation in light source intensity, vanes across the visual field and often will be unno-
usually most noticeable in peripheral vision. The output ticed. Designers are cautioned to consult with a lamp
of lighting systems that operate on alternating current manufacturer about the flicker index of a particular
power varies in output at a rate that is twice the cyclic fluorescent lamphallastcombination before it is used in
frequency of the input power. Sometimes this “strobe an area where flicker or strobe could be a problem.
effect” appears to slow or even stop the movement of
objects. This can be annoying or dangerous for opera- The flicker in HID lamps depends on the lamp type
tors of rotating or other rapidly cycling equipment. and the ballast circuit. Figure 5 illustrates the varia-
tion in flicker index for mercury (used infrequently
The “flicker index” has been established as a reliable today), metal halide and high pressure sodium lamps
relative measure of the cyclic variation in output of for several ballast types operated at 60-Hz. The flick-
various light sources at a given power frequency and er index is considerably higher in 50-Hz power sys-
takes into account the waveform of the light output as tems. Using electronic ballasts having high-frequen-
well as its amplitude. The flicker index assumes val- cy or rectangular wave characteristics can be effec-
ues from O to 1.0 with zero for steady light output. tive in reducing the flicker effect. Operating fluores-
Higher values indicate increased possibility of notice- cent or HID lamps on alternate phases of a three-
able stroboscopic effect as well as lamp flicker. phase power supply will reduce observed flicker
when the light from luminaries connected to all three
Most fluorescent lamps have low flicker indices, and phases is well mixed before it reaches the workplane.
typically do not cause problems when operating on a This is accomplished by using luminaries with a wider
60-Hz power supply. Their visible flicker is virtually elim- spacing criterion, designing for 50 percent light pat-

Figure 5. Flicker Index for HID Lamps Operated on Different Ballast Types.

Lamp Type Ballast Flicker Index

Mercury
250W Warm Deluxe Reactor O. 127
250W Cool Deluxe Reactor 0.137
250W Deluxe White Reactor 0.131
250W Deluxe White CWA íM-H tvDe) O. 172
I 1OOW Deluxe White I CW-Prem ¡um I 0.142 I
1OOW Deluxe White cw O. 183
400W Deluxe White Reactor 0.121
400W Deluxe White CWA (M-H type) 0.144
--``````-`-`,,`,,`,`,,`---

250W Deluxe Reactor or CWA 1 0.131

I 250W Standard I Reactor or CWA I 0.200 I
Metal halide
250W High Color Quality Reactor 0.080
250W High Color Quality HPS-CWA 0.102
175W Coated CWA 0.083
I 175W Clear-Vertical I CWA I 0.078 I
175W Clear-Horizontal CWA 0.092
175W (3200K) CWA 0.090
250W Coated (A) CWA 0.070
250W Clear-Vertical CWA 0.102
250W Clear-Horizontal CWA 0.121
250W Coated (B) CWA 0.092
250W Clear-Vertical CWA-Premium 0.088
250W Clear-Horizontal CWA-Premium 0.097
400W Clear-Vertical CWA 0.086
400W Clear-Horizontal CWA 0.095
1OOOW Clear (vert.) CWA 0.067
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 ANSI / IESNA RP-7-01

tern overlap, and powering adjacent luminaries from gold, straw and wheat downlight reflectors or selecting
alternate phases. among various screw or wire insulation colors.

3.8 Color Rendering The need for high color rendering sources varies wide-
ly throughout industrial facilities. In warehouse areas,
The selection of a lamp color for an industrial facility the task may be reading black printing against the
requires consideration of at least two factors, color color of a cardboard package. In this example, a lamp
appearance and the color rendering ability of the with the very low color rendering index may not only
source. The color appearance is important to create a suffice, but also actually enhance the visibility of the
pleasant and attractive atmosphere in which to work printing by increasing the contrast of the visual task.
and a space that will promote high productivity. On the other hand, where color comparison or color
discrimination is critical, it will be necessary to select a
Color rendering is the general expression for the source with a high color rendering index to provide the
effect of a light source on the color appearance of an color quality necessary to perform those visual tasks.

--``````-`-`,,`,,`,`,,`---
object compared to the color appearance under a ref-
erence light source. Daylight and incandescent light 3.8.2 Safety Colors
sources are generally thought of as having “good
color rendering properties because objects look the Safety colors are used to indicate the presence of a
way we expect them to look under those sources. safety hazard, such as an open pit or a lift truck traffic
Fluorescent and HID lamps may have a wide range of lane, or a safety facility, such as a first aid station.
color rendering properties depending on the composi- These are carefully developed colors, which are spec-
tion of the arc tube gases and the materials coating ified in American National Standard 2535.1-1998,
the inside of the lamp envelope. Safety Color Code. The background around these
colors should be kept as free of competing colors as
3.8.1 Color Rendering Index, (CRI) possible, and the number of other colors in the area
should be kept to a minimum. Illumination in the area
The Color Rendering Index (CRI) is a system recom- of safety color markings should permit positive identi-
mended by the International Commission on fication of the color, hazard or situation without distor-
Illumination (Commission Internationale de I’Eclairage tion or obscuration of the message to be conveyed.
(CIE)) for measuring and specifyingthe ability of a light
source to render colors. The system rates a lamp’s The specification of these colors is given in Figure 6.
CRI in terms that represent the degree of color shift of Designers must be aware that these specifications
an object under a test lamp in comparison with its color have been developed based on CIE standard illumi-
under a standard lamp of the same correlated color nant “ C (a laboratory simulation of the spectral power
temperature. Note that CRI is only useful when com- distribution of average daylight). Therefore, the colors
paring two or more lamps of the same correlated color will be recognizable under daylight, conventional incan-
temperature. Lamp CRIS used where color rendering descent and fluorescent sources, which have a broad
is unimportant may be as low as 20. When color ren- spectrum. Note that high intensity discharge sources
dering is important, the CRI should exceed 70. Where render some colors differently than these other source
color rendering is critical, the CRI should exceed 85. types. This may cause some confusion in recognition of
safety colors at illuminances of 5 lux (0.5 fc) and lower.
The color rendering index of the lamps selected for the
lighting system design should permit the workers to effi- 3.9 Daylight Integration and Control
ciently and safely perform their tasks. Many industrial
operations now require color discrimination during the A view of the outdoors is believed to be important for
manufacturing process. Instances have arisen where human psychological and physiological reasons. While
an HID source with a relatively low color rendering daylight can be used to help light a space, extra care
index has been used in a space where color coding should be taken in industrial environments to control
was employed in production control and scheduling. the quantity and distribution of the light and its associ-
The colors of the codes were not readily identifiable ated heat gain. It should be noted that more illuminance
under the low color rendering HID source. The solution is sometimes needed on interior surfaces near win-
was to provide supplementary lighting with fluorescent dows to reduce the contrasts between those surfaces
lamps having a higher color rendering index, permitting and the windows. Daylighting is most effective for many
the workers to direct the operations with the necessary interior spaces when used as ambient illuminance, but
speed and efficiency. Color discrimination can be nec- it is too variable to be considered a reliable source for
essary during assembly and “parts picking.” For exam- task illuminance in industrial applications. (For informa-
ple, in the lighting industry, the parts selection task tion on the subject of daylighting see IESNA RP-5-99,
might involve discerning between gold, champagne Recommended Practice of Daylighting.)

10
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Figure 6. Specification of ANSI Safety Colors Viewed under CIE Standard Illuminant C.
Color Name

Safety Red
Munsell Notation

7.5R 4.0114
v
A

0.5959
CIE Specification
V

0.3269
V
12.00
ISCC-NBS Name

Vivid Red
1
Safety Orange 5.OYR 6.0115 0.5510 0.4214 30.05 Vivid Orange
Highway Brown 5.OR 2.7515 0.4766 0.3816 5.52 Moderate Brown
Safety Yellow 5.0Y 8.0112 0.4562 0.4788 59.10 Vivid Yellow
Safety Green 7.5G 4.019 0.21 10 0.4 120 12.00 Strong Green
Safety Blue 2.5PB 3.5110 O. 1690 0.1744 9.00 Strong Blue
Safety Purple 1O.OP4.5110 0.3307 0.2245 15.57 Strong Reddish Purple
Safety White N9.01 0.3101 0.3 162 78.70 White
Safety Gray N5.01 0.3101 0.3 162 19.80 Medium Gray
Safety Black N1.51 0.3101 0.3 162 2.02 Black

Occasionally the visual task in a specific space is

4.0 QUANTITY OF LIGHTING IN INDUSTRIAL
not typical. The information in Annex A l should be
FACILITIES used to adjust the illuminancefor that task. In addi-
tion, illuminance recommendations for tasks/
spaces/industries not covered in Figure 1(a) are
The recommended illuminances provided in the Lighting contained in Annex A2.
Design Guide (Figure 1 (a)) are based on the Society’s
consensus judgement of best practice for ‘Yypical” appli- 4.1 Illuminance: Horizontal, Vertical and Inter-
cations. Typical conditions, however, may not be appro- mediate Planes
priate for a specific application. As a professional, the
lighting designer should have a better understanding of For the first part of the 20thCentury, when “lighting
the particular space and the needs of occupantdclients levels” were discussed, it was usually understoodthat
than that which can be represented by a recommended the referencewas to illuminanceon the horizontal sur-
illuminance value for a typical space. The lighting needs face. As more has been learned, it is now known that
and requirements of an individual industrial facility will a horizontal plane is not the only plane that is impor-
depend on many factors. Certain facilities may include tant, particularly in an industrial facility. For that rea-
multiple lighting needs within the same production area, son, note that when determining illuminance, the ori-
resulting in the deliberate use of non-uniform lighting. entation of the task (horizontal, vettical or intermedi-
ate inclined plane) should be known.
Beginning in 1979, the IESNA established nine illumi-
nance categories (A through i),and these were used 4.1.1 Horizontal Illuminance
in previous editions of this recommended practice.
Each category had general descriptions of the visual Horizontal illuminance is important and should not be
task, irrespective of the application. This system has ignored. This is the light that allows us to predict how
now been modified in the following significant ways: clearly tasks and items will be seen when they are on
a flat work surface, shelf or on the floor. Horizontal illu-
The recommended illuminances on industrial task minance is important for task visibility, material han-
planes are now provided with reference to a spe-
--``````-`-`,,`,,`,`,,`---

dling and general circulation. Uniform horizontal illu-

cific application. The tasks may be horizontal, minance (where the maximum level is not more than
inclined or vertical. one-sixth above the average level, and the minimum,
not more than one-sixth below) is frequently appropri-
The nine original illuminance selection categories ate for specific industrial interiors where tasks are
have been reduced to seven categories and orga- closely spaced and where there are similar tasks
nized into three sets of visual tasks [orientationand requiring the same amount of light. In such instances,
simple (A, B, C), common (DI E, F) and special uniformity permits flexibility of functions and equip-
(G)]. The seven new letter categories are present- ment locations. Neighboring areas with extreme lumi-
ed and described in Figure 1 (b). They also appear nance differences are undesirable because continu-
in the “Illuminance” columns of Figure 1 (a). ously adapting between two significantly different
luminance levels physically adjacent to each other
Guided by scientific literature and practical experi- can be visually fatiguing to the worker. Uniformity may
ence, IESNA’s recommended illuminance values be more important in industrial lighting than in some
now increase roughly logarithmically with increas- other applications. While non-uniformlighting can add
ing task difficulty. interest in applications that are of a more aesthetic
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nature, industrial spaces can benefit from high-quality Industrial tasks come in all shapes and sizes. Flat
uniform lighting when the location of the task cannot tasks may be viewed in a horizontal plane or in planes
always be accurately predicted. Uniform lighting also at any number of other angles. The visual task asso-
allows repositioning of task locations or production ciated with solid parts can be made more visible by a
machinery without needing to relocate luminaries. number of means including supplemental lighting and
This can be particularly beneficial in high-bay industri- shadowing to emphasize the shape of the object.
al facilities where the cost and inconvenienceof mov- Harsh shadows should be avoided, but some shadow
ing luminaries located 9 m (30 feet) or more above the effect may be desirable to accentuate the depth and
production floor can be substantial. form of objects. There are a few specific visual tasks
where clearly defined shadows improve visibility, and
There are instances where non-uniform lighting is such effects should be provided by supplementary
appropriate. Maintaining uniformity between adjacent lighting equipment arranged for the particular task.
areas, which have significantly different visibility (and Refer to the material in Section 12.0, Supplementary
illuminance) requirements, may be wasteful of energy Lighting for more information.
- for example, a storage area adjacent to a machine
shop. In such instances, different lighting levels are Industrial lighting design requires a great deal of infor-
required, according to the needs of the space. This mation about the tasks to be performed in the space.
may be accomplished by using similar luminarieswith Because of this, the lighting designer should carefully
different lamp wattages or distributions, different num- discuss the manufacturing process with the facility
bers of lamps per luminaire or by adjusting the num- personnel to obtain sufficient background information
ber of luminaries per unit area, making sure the other for proper evaluation of all of the design requirements.
requirements of the lighting design are met. Personal visits to similar operations can be invaluable
and are recommendedwhenever practical. Interviews
4.1.2 Vertical Illuminance. with workers can also reveal information that might
otherwise not be seen directly.
In an industrial setting, vertical illuminance, and the
illuminance at other planes between horizontal and 4.2 Initial and Maintained Illuminance
vertical, is very important. In many large-partsassem-
bly areas, work takes place on the underside of a The quantity of light (illuminance) required depends
major component, such as the wing or fuselage of an primarily upon the seeing task, the time to perform the
aircraft. Work performed deep within the recesses of task, the worker, and the importance of the various
production equipment such as presses, breaks or task parameters in performing the work.
molding machines requires that the light penetrate
into the machine to the location of the task for effi- The illuminancewill determine the worker’s adaptation
ciency and safety. This may be accomplished by to the visual environment. In today’s industrial facilities,
using wide-distribution general lighting equipment there may be hazards, such as cranes, fork-lift trucks,
(with a majority of the light output 40” to 70” from the conveyors and rotating machinery, which can affect the
vertical). Light is reflected at high angles and high illuminance requirements. In locations where dirt accu-
reflectance surfaces are provided in the work area. mulates rapidly and adheres readily to luminaire and
The use of supplementary lighting also helps to put room surfaces, and where maintenance is inadequate
the light directly on the task. to keep lighting systems operating at design levels, the
“light loss factor” used in calculating the required illumi-
Diffuse light, including up-light components, from lumi- nance must be reduced, thereby increasing the initial
naries with very wide distribution (such as “low bay” illuminance, to compensate for the poor maintenance.
HID luminaries) can have additional benefits in an This practice is not necessarily energy efficient, but
industrial environment. The wide distribution can miti- may be justified to assure the worker has adequate
gate the effects of lamp outages in a single luminaire light to safely and efficiently perform the required visual
and may allow production to continue in a normal man- tasks. Other measures are available to compensate for
ner without having to spot-replace lamps as they fail. the loss of light normally experienced through the life of
Wide-distribution luminaries also tend to produce a a lighting system. Automatic control systems can offset
the degradation of the lighting system due to age.
--``````-`-`,,`,,`,`,,`---

higher level of vertical illuminance (and wall luminance),

at some sacrifice in horizontal illuminance. This can be Automatic switching systems can turn lights off when
a definite advantage where the seeing task is in a plane they are not needed, or switch them into a power-sav-
other than horizontal and there is a need to increase ing mode, provided that occupancy sensors are used
the vertical component of the lighting for task visibility. for returningthe lights to operating levels.
Care must be exercised, however, to ensure that the
wider light distribution does not produce discomfort or The number of luminaries required to meet the rec-
disability glare beyond workers’ tolerances. ommended illuminance can be calculated using a

12
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basic manual procedure (such as the Lumen Method and with the luminaire’s auxiliary equipment. In addi-
in Annex C ) or any of a number of commercially tion, the envelope of the replacement lamps must
available computer based calculation programs to match the original lamp design in shape and finish
calculate the number of luminaries required. It is (coated or clear). Using the wrong lamp type can
important that the lamp and luminaire characteristics, completely change the luminaire photornetrics and
light loss factors and room characteristics discussed create entirely new lumen distribution patterns in the
later be carefully selected to assure the acceptability space. The lamp and ballast specifications from the
of the installed lighting system. Many computer based American National Standards Institute (ANSI) and
lighting calculation programs now allow partitions and Canadian Standards Association (CSA) should be
equipment to be included in the input data resulting in matched to assure proper lamp operation in both new
a more realistic modeling of the space. and relamping situations.

4.3 Lighting System Maintenance Information on operating and maintaining the lighting
system should always be documented for facility
Industrial facilities often present challenging mainte- operating and maintenance personnel. As an exam-
nance problems. Luminaries may be located far ple, lamp manufacturers direct that certain metal
above the floor over large production equipment. halide lamps may be used in open luminaries only if
Plant operations often will not tolerate interruptionsfor there is a schedule to cycle the lamps off at least once
lamp and luminaire maintenance. Where cranes are a week and to group relamp the area containing those
present in high bay areas, they can often be used as lamps. These instructions are usually printed on the
the maintenance platform. This may be possible dur- paper sleeve in which the lamp is shipped but that
ing normal production times but, more often, mainte- information may or may not be noted. For this reason,
nance will have to be performed during non-produc- it is good practice to provide the owner’s, or occu-
tion times. Platforms may be used to service lighting pant’s maintenance personnel with complete and
equipment or disconnecting hangers installed to per- clear written lighting system maintenance instructions
mit the luminaireto be disconnected by chain or cable at the time the project is completed.
from the floor or some intermediate level and lowered
to permit servicing from that level. Where the layout of Target illuminance levels are rarely achieved without
the space will permit, telescoping platforms can pro- some consideration during the initial design about the
vide the necessary access to luminaries. nature of on-site maintenance. This further demon-
strates the need for providing a written maintenance
Good maintenance programs can be effective in program recommendation to assure the continued
reducing the total power of an installed lighting sys- integrity of the design.
tem. A shorter relamping and cleaning cycle can
reduce the number, or wattage, of the luminaries and,
thereby, reduce the electrical load of the lighting sys- 5.0 GENERAL LIGHTING EQUIPMENT
tem. Dependingon the system, illuminance levels can
depreciate to less than half of their initial level when
lamps are replaced only as they fail, even if luminar- All lamp performance data such as life, lumen output
ies are thoroughly cleaned at relamping. Better light and color are based upon statistical data. Lamp life,
loss factors occur when systems are group relamped for instance, is the point in time when half of the lamps
and cleaned at a shorter interval (typically 70 percent have failed and half are still operating. Lamp life is
of rated life). The savings in labor usually offset high- also dependent upon the number of hours per start
er lamp costs from a group maintenance program. A (for example, 10 hrs/start vs. 120 hrdstart). It is impor-
significant capital and operating (principally electric tant that the designer have a working knowledge of
energy) cost saving is associated with programmed the underlying statistics in order to properly evaluate
maintenance. Figure 7 shows the effect of cleaning and/or compare systems and components..
and relamping on the output of a fluorescent lighting
system and how these maintenance operations can 5.1 Fluorescent Systems
have a beneficial effect on the system output.
5.1.1 Source Characteristics
It is critical to the proper operation of the lighting sys-
tem that replacement lamps have not only the same Among the advantages of fluorescent lamps are their
electrical characteristics as the original lamps, but high luminous efficacy and relatively low brightness.
also the same envelope and color rendering charac- That is, low brightness to the extent that open-reflec-
teristics. It is obvious that the lamp must fit in the lumi- tor luminaries are often used in situations that have
naire’s socket and that the lamp’s electrical character- high wall and ceiling reflectances with low risk that
istics must permit operation on the system voltage workers will complain of excessive glare.
--``````-`-`,,`,,`,`,,`---

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No reproduction or networking permitted without license from IHS Not for Resale
 ANSI / IESNA RP-7-01

1O0
-A

-B
90 -C

-D

80
-E
-F
70
)

c
æ
a
c
8 60
Ern
-
.-
- 57 I I I I I I
.-m
.-c
C
; 50
al
C
rn
._
v>
al
U -Ik-2-4-3.-4-I
+
o
c 40 Clean Clean Clean Clean
c luminaires luminaires luminaires luminaires
al
2 once and per 18 months; per 18 months; per 12 months;
al
a relamp 100% relamp 100% relamp 50% relamp 33-1/3%
once per once per once per once per
36 months 18 months 18 months 12 months
30

20
=
Í I
A-Temperature and voltage

B-Luminaire deterioration
=
B
I
D-Lamp

E-Lamp
lumen depreciation (LLD)

burnouts

10
C-Room surface dirt F-Dirt accumulation on lamps
accumulation and luminaires

O
O 3 6 9 12 15 18 21 24
Time in years

Figure 7. Effect of light loss factors on illuminance. Example uses 32-watt rapid-start lamps, operated 10 hours
per day, 5 days per week, 2600 hours per year. All four maintenance systems are shown on the same graph for
convenience. For a relative comparison of the four systems, each should begin at the same time and cover the
same period of time. --``````-`-`,,`,,`,`,,`---

A disadvantage is that the luminous flux generated is lamps with halo phosphors.
related to the surface area of the source; the greater
the length, the higher the efficacy. In recent lamp Lamp life is determined by the rate of loss of the emis-
designs, as the diameter of the lamp has been sive coating on the electrodes or electrode failure.
reduced, the lumens per unit area of the lamp surface End of lamp life is reached when the coating is com-
area have increased. pletely removed from one or both electrodes. The
rated average life of fluorescent lamps usually is
The light output of fluorescent lamps decreases based on three hours of operation per start (3 hlstart).
with accumulated operating time because of degra-
dation of the phosphor coating and accumulation of Fluorescent systems offer the best color rendering
light-absorbing deposits within the lamp. Protective ability over the widest ranges of apparent chro-
coatings are sometimes used to reduce the phos- maticity (correlated color temperature (CCT) mea-
phor degradation. Lamps with rare earth phospho- sured in Kelvin).
rs (T-5 or T-8) have better lumen maintenance than
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 ANSI / IESNA RP-7-01

5.1.2 Fluorescent Luminaire Characteristics1 utilization in narrow or obstructed spaces) or at the

Performance spacing limit in order to obtain a wider spacing criteri-
on. Other reflectors may be designed for wide or
The most commonly used fluorescent general lighting asymmetric distribution. It is importantto use the lamp
luminaries for industrial applications are 8 feet long, type specified since lamps and reflectors are
multi-lamped with T-8 or in some older installations, designed to work in combination. As always, the
the less efficient T-12 lamps. T-8, 800ma lamps oper- improvement in visual comfort must be balanced with
ated on high frequency electronic ballasts may repre- efficiency and maintenanceconcerns. If greater cutoff
sent the best performance. Recent developments in is required, select a deeper reflector.
performance of smaller diameter (T-5 and T-2) lamps
offer suitable solutions for supplementary lighting. Spacing criterion (SC)may be an unreliable gauge of
Most retrofits of industrial fluorescent luminaries use how far apart general lighting luminaries can be
4‘ T-8 lamps. spaced while still providing acceptable uniformity of
horizontal illuminance.Typically, fluorescent industrial
One benefit of fluorescent luminaries is that most two- luminaries have spacing criteria of 1.3 to 1.6. (See
lamp systems with electronic instant start ballasts Figure 8 page 16.)
(parallel lamp operation) offer redundancy; approxi-
mately half the light is still supplied if one lamp fails. 5.2 High Intensity Discharge (HID) Lighting
Systems
The luminous performance (efficacy or light output)
and color of a fluorescent lamp result from the mer- Because mercury vapor lamps have operating char-
cury vapor pressure within the lamp, which depends acteristics that are far inferior to both metal halide and
on temperature. The internal temperature of a lumi- high pressure sodium lamps for general lighting pur-
naire can adversely affect the life of some types of flu- poses, their use in modern industrial plants is rare.
orescent lamps. High ambient temperatures not only Therefore, this discussion of HID lamps for general

--``````-`-`,,`,,`,`,,`---
lower the lamp’s lumen output but also can change lighting in industrial facilities does not include mercury
the electrical characteristics, bringing them outside vapor lamps. The reader should contact lamp manu-
the design range of the ballast. Long-term operation facturers for mercury vapor lamp information.
at higher currents shortens the life of the lamp.
5.2.1 Metal halide Lamps
The best fluorescent general lighting systems employ
opaque sided reflectors for each lamp, with a 35- Metal halide (MH) lamps are similar in construction to
degree lamp cut-off along the luminaire transverse the earlier and simpler mercury vapor lamps. One of
axis (across the luminaire), and louvers that provide the major differences is the metal halide compounds
similar cut off along the longitudinal axis (along the included in the arc tube, which improve the color ren-
luminaire). Luminariesoffen have apertures at the top dering qualities of metal halide lamps compared to
that allow up-light and air movement. Air movement those of even phosphor-coated mercury lamps. It is
enables cleaner operation over an extended period of also possible, by adjusting the mix of the elements
time in most open luminaries. included in the arc tube, to vary the chromaticity of
metal halide lamps. Metal halide lamps are available
Fluorescent luminaries are generally considered for in wattages from 35 to 1000 watts. (There are 1500
installation up to 6.0 m (20 ft) above the floor or plat- watt lamps used primarily for sports lighting applica-
form level. However, with the proper combination of tions. ) The efficacy of MH lamps is greatly improved
fluorescent lamps, ballasts and reflector design the over mercury vapor with typical values of 75 to 125
use of fluorescent systems has been successfully lumens/watt (not including ballast losses). Metal
expanded to mounting heights of 13.6 m (45 ff). halide lamps are made in both clear and coated outer
bulb configurations and it is important that the correct
White finished diffuse reflector surfaces are the most lamp type be used in the luminaire to assure the
common and are generally very efficient. Mirror fin- lumen distribution for which the luminaire was
ished optical surfaces vary widely in efficiency designed.
depending on the specific materials used and gener-
ally have lower apparent brightness when viewed Many metal halide lamps are life and lumen rated for
from the side. Better optical control, available by using operating in the vertical position. Using lamps
mirror finishes, may be desirable in narrow confining designed for vertical operation in a horizontal operat-
spaces or where obstructions block light from adja- ing position can seriously affect the lamp life and
cent luminaries. The fluorescent source size may lumen output. For this reason, horizontal operating
interfere with the optical designer’s attempt to direct lamps have been specifically designed. These lamps
source output at specific angles. This is often done to will provide about 33 percent increase in life and
increase luminaire intensity at either nadir (for better approximately 25 percent increase in lumen output
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 ANSI / IESNA RP-7-01

Figure 8. Typical Fluorescent Luminaries.

--``````-`-`,,`,,`,`,,`---

Typical Intensity
Distribution
DCC-1 1 80
70 I 50 I 30 1 10 1
0
Typical Luminaire
pw-1 I 70 50 30 70 50 30 I 50 30 10 I 50 30 10 1 50 30 10 IÕ
":1 " EFF = 90.5% % DN = 78.2% % UP = 21.8%
Lamp = (2) F40T12
SC (along, across, 45') = 1.3. 1.5, 1.5
~

0.98 0.98 0.98 0.82 0.82 0.74 0.74 0.74 0.71

0.89 0.85 0.81 0.68 0.66 0.64 0.62 0.61 0.58
0.80 0.74 0.68 0.58 0.54 0.56 0.53 0.50 0.47

Eh;
0.77 0.67 0.60 0.73 0.64 0.58 0.49 0.45 0.49 0.45 0.42 0.40
0.70 0.59 0.51 0.66 0.57 0.50 0.43 0.39 0.44 0.39 0.36 0.33
0.64 0.53 0.45 0.61 0.51 0.43 0.37 0.33 0.39 0.35 0.31 0.29
0.59 0.47 0.39 0.56 0.45 0.38 0.33 0.29 0.35 0.31 0.27 0.25
0.52 0.41 0.34 0.30 0.26 0.32 0.28 0.24 0.22
0.51 0.39 0.31 0.48 0.37 0.30 0.27 0.23 0.29 0.25 0.21 0.19
Industrial, white enamel reflector, 20% up 0.45 0.34 0.27 0.24 0.20 0.27 0.23 0.19 0.17
0.42 0.31 0.25 0.22 0.18 0.25 0.21 0.17 0.16

EFF = 86.9% % DN = 100%

-
1.01 1.01 1.01 0.97 0.97 0.97 0.92 0.92 0.92 0.89 0.89 0.89 0.87
0.92 0.88 0.84 0.84 0.81 0.79 0.81 0.79 0.76 0.78 0.76 0.74 0.72
0.85 0.78 0.72 0.83 0.76 0.70 0.73 0.68 0.64 0.70 0.66 0.63 0.67 0.64 0.61 0.59
0.77 0.68 0.60 0.75 0.66 0.59 0.64 0.58 0.53 0.61 0.56 0.52 0.59 0.55 0.51 0.49
0.70 0.60 0.52 0.68 0.58 0.51 0.56 0.50 0.45 0.54 0.48 0.44 0.52 0.47 0.43 0.41
0.65 0.53 0.45 0.63 0.52 0.44 0.50 0.43 0.38 0.48 0.42 0.38 0.47 0.41 0.37 0.35
0.59 0.47 0.39 0.58 0.47 0.39 0.45 0.38 0.33 0.43 0.37 0.33 0.42 0.37 0.32 0.31
0.55 0.43 0.35 0.53 0.42 0.35 0.41 0.34 0.29 0.39 0.33 0.29 0.38 0.33 0.29 0.27
0.51 0.39 0.31 0.50 0.38 0.31 0.37 0.30 0.26 0.36 0.30 0.26 0.35 0.29 0.25 0.24
Industrial, white enamel reflector, down only 0.48 0.36 0.28 0.46 0.35 0.28 0.34 0.28 0.23 0.33 0.27 0.23 0.32 0.27 0.23 0.21
0.43 0.32 0.25 0.31 0.25 0.21 0.31 0.25 0.21 0.30 0.24 0.21 0.19
-

EFF = 89.3% % DN = 86.4%

O 1.03 1.03 1.03 1.00 1.00 1.00 0.92 0.92 0.92 0.86 0.86 0.86 0.80 0.80 0.80 0.77
1 0.93 0.88 0.83 0.89 0.84 0.80 0.78 0.75 0.72 0.73 0.70 0.68 0.67 0.65 0.63 0.61
2 0.83 0.75 0.68 0.80 0.72 0.66 0.67 0.62 0.58 0.62 0.58 0.55 0.58 0.55 0.52 0.49
3 0.75 0.65 0.57 0.72 0.63 0.56 0.58 0.52 0.47 0.54 0.49 0.45 0.50 0.46 0.43 0.40
4 0.69 0.57 0.49 0.65 0.55 0.47 0.51 0.45 0.40 0.48 0.42 0.38 0.44 0.40 0.36 0.34
5 0.63 0.51 0.42 0.60 0.49 0.41 0.46 0.39 0.34 0.43 0.37 0.32 0.40 0.35 0.31 0.29
6 0.58 0.45 0.37 0.55 0.44 0.36 0.41 0.34 0.29 0.38 0.32 0.28 0.36 0.31 0.27 0.25
7 0.53 0.41 0.33 0.51 0.40 0.32 0.37 0.30 0.26 0.35 0.29 0.25 0.33 0.27 0.24 0.22
8 0.50 0.37 0.29 0.47 0.36 0.29 0.34 0.27 0.23 0.32 0.26 0.22 0.30 0.25 0.21 0.19
9 0.46 0.34 0.26 0.44 0.33 0.26 0.31 0.25 0.20 0.29 0.24 0.19 0.27 0.22 0.19 0.17
2-Lamp bare strip 10 0.43 0.31 0.24 0.41 0.30 0.23 0.29 0.22 0.18 0.27 0.21 0.18 0.25 0.20 0.17 0.15

Lamp = (3) F32T8

EFF = 72.7% % DN = 100 %UP=O SC (along, across, 45') = 1.3, 1.6, 1.6

!
O 0.87 0.87 0.87 0.85 0.85 0.85 0.81 0.81 0.81 0.77 0.77 0.77 0.74 0.74 0.74 0.73
1 0.81 0.78 0.76 0.79 0.77 0.74 0.74 0.72 0.70 0.71 0.69 0.68 0.68 0.67 0.66 0.65
2 0.75 0.70 0.66 0.73 0.69 0.65 0.66 0.63 0.61 0.64 0.61 0.59 0.62 0.60 0.58 0.57
3 0.69 0.63 0.58 0.68 0.62 0.57 0.60 0.56 0.52 0.58 0.54 0.52 0.56 0.53 0.51 0.49
4 0.64 0.56 0.51 0.62 0.55 0.50 0.54 0.49 0.46 0.52 0.48 0.45 0.51 0.47 0.44 0.43
5 0.59 0.51 0.45 0.58 0.50 0.44 0.48 0.44 0.40 0.47 0.43 0.40 0.46 0.42 0.39 0.38

'
8 0.55 0.46 0.40 0.53 0.45 0.40 0.44 0.39 0.35 0.43 0.38 0.35 0.42 0.38 0.35 0.33
7 0.51 0.42 0.36 0.50 0.41 0.36 0.40 0.35 0.31 0.39 0.35 0.31 0.38 0.34 0.31 0.30
2 x 4, 3-Lamp parabolic troffer with 3 semi-spec.
8 0.47 0.38 0.32 0.46 0.38 0.32 0.37 0.32 0.28 0.36 0.31 0.28 0.35 0.31 0.28 0.27
louvers, 18 cells 0.44 0.35 0.29
9 0.43 0.35 0.29 0.34 0.29 0.25 0.33 0.29 0.25 0.32 0.28 0.25 0.24
10 0.41 0.32 0.27 0.40 0.32 0.27 0.31 0.26 0.23 0.31 0.26 0.23 0.30 0.26 0.23 0.22

Lamp = (3) F40T12

EFF = 66.2% %DN=100 %UP=O SC (along, across, 45') = 1.3, 1.6, 1.5
-- --
0.77 0.77 0.74 0.74 0.70 0.70
0.72 0.70 0.66 0.64 0.65 0.64
0.67 0.63 0.58 0.56 0.59 0.57
0.63 0.58 0.53 0.62 0.57 0.51 0.48 0.53 0.50
0.59 0.52 0.47 0.57 0.51 0.46 0.42 0.48 0.45
0.54 0.47 0.42 0.53 0.46 0.41 0.37 0.44 0.40
0.50 0.43 0.37 0.49 0.42 0.36 0.33 0.40 0.36
0.47 0.39 0.33 0.46 0.38 0.33 0.30 0.36 0.32
2 X 4, 3-Lamp parabolic troffer with 4" semi-spec. 0.44 0.35 0.30 0.43 0.35 0.30 0.26 0.33 0.29
louvers, 18 cells 0.41 0.33 0.27 0.40 0.32 0.27 0.24 0.31 0.27
0.37 0.30 0.25 0.22 0.28 0.24
-- -- --

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 ANSI / IESNA RP-7-01

over universal burning position lamps when operated tion characteristics than other metal halide lamp
in the horizontal position. A special base and socket types. This will make these lamps more attractive
are required for all of the horizontal burn, high-output, choices in some industrial environments. At the time
MH lamps to assure the arc tube is properly posi- of publication, ceramic metal halide lamps are avail-
tioned. These lamps should always be used in lumi- able in ratings from 39 to 400 watts.
naries equipped with the proper socket.
Cost may become a determining factor in the choice
Because MH arc tubes produce high-energy ultravio- between the widening selection of metal halide lamps
let radiation, some lamps are manufactured with an and HPS lamps in the short term, but that must be fol-
electrical cutout that will automatically extinguish the lowed closely and weighed against the benefits of the
lamp if the outer envelope should crack or rupture in a improved characteristics of the MH lamps.
manner that would normally still allow the arc to oper-
ate. These lamps should be used in locations where it 5.2.2 High Pressure Sodium (HPS) Lamps
is necessary to limit UV radiation and where the lumi-
naire will not provide the necessary protection. Most HPS lamps can operate in any position. The
operating position has no significant effect on light
Transparent sleeves (shrouds) may be used internal- output. Lamps are also available with diffuse coatings
ly in some single ended (screw-base) MH lamps for on the inside of the outer bulb to increase source lumi-
two reasons. Thin walled shields are used to help nous size or reduce source luminance.A diffuse coat-
achieve a more uniform arc tube temperature, which ing, however, does not increase the CRI of the lamp.
--``````-`-`,,`,,`,`,,`---

will improve the lamp performance. Heavy walled

shrouds are used on lamps designed for use in open HPS lamps have high lamp efficacy (lumenshatt), and
luminaries. The heavy walled shroud is designed to long life. They are available in wattages from 35 to 1O00
contain the hot quartz particles and protect the outer watts. The color rendering ability of HPS is not as good
bulb of the lamp from breaking in the event the arc as metal halide lamps. Color improved HPS lamps are
tube should fail. available but at a sacrifice in efficacy and life.

5.2.1.1 Pulse-start and Ceramic Metal halide The life of an HPS lamp is limited by a rise in operat-
Lamps ing voltage that occurs over the life of the lamp. When
the ballast can no longer supply enough voltage to
The choice between metal halide (MH) and high pres- reignite the arc during each electrical half-cycle, the
sure sodium (HPS) high intensity discharge (HID) lamp extinguishes. When it cools down, the lamp will
lamps was, until recently, a choice between the supe- again ignite and warm up until the arc voltage rises so
rior color of MH (although some MH lamps display that the ballast cannot support the arc. This cycling
strong color shift near end-of-life) versus the improved process occurs until the lamp is replaced. This cycling
lumen output and longer life of HPS. HPS was fre- can cause annoyance and, more important, a varia-
quently the choice. Recently, however, the advent of tion in light output and distribution in a production
pulse-start (high wattage 175W - lOOOW, and low area, underlining the need for a planned relamping
wattage 35/39W - 150W) and ceramic metal halide program. Cycling also overworks the ignitor, eventual-
lamps has blurred the line between these choices. ly causing it to fail.

The pulse start lamps have improved starting .times, HPS lamps are also available in a double arc tube
some starting as much as three times faster than con- configuration with two identical arc tubes contained
ventional MH lamps. They also start more reliably, within the outer envelope. These arc tubes are con-
have better lumen maintenance, improved lamp life, nected in parallel inside the lamp, but only one arc
and reduced restrike times. The cost of a pulse start tube is started with the ignitor pulse. In the event of a
metal halide luminaire and lamp may run from 5-10 momentary power outage, this dual arc tube lamp
percent more than a conventional luminaire/lamp restrikes immediately when power is restored. Within
combination but the cost may be easily justified by the about one minute, the lamp returns to full light output.
improved performance.
5.2.3 Luminaire Selection
Ceramic metal halide lamps are used when color ren-
dering and color consistency are a priority. They Industrial HID luminaries are generally divided into
achieve over 80 CRI by utilizing higher fill pressures -
two categories High-Bay and Low-Bay. These cate-
and operating at higher temperatures.They also have gories are not well defined throughout the lighting
the potential for longer life, with some expected to industry. Therefore, for the sake of consistency in this
achieve significantly higher life ratings, more stable Recommended Practice, they are defined as follows:
color, higher lumen output and better lumen deprecia-
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High-Bay luminaries designed to produce gener- where the luminaries are actually located at approxi-
al illumination in the space where the application mately 0.65 times the mounting height will usually pro-
requires a spacing to mounting height ratio of 1.O vide the desired overlap. If the luminaries are to be
or less and where the mounting height is not less located closer together than dictated by the luminar-
than 7.6 m (25 fi). ies’ spacing criteria, a spacing adjustment should be
considered when the lighting calculations are per-
Low-Bay luminaries designed to produce general formed to assure the proper illuminance and lighting
illumination in the space where the application quality in the final installation.
requires a spacing to mounting height ratio greater
than 1.0 and where the mounting height is less 5.2.3.2 Low-Bay Luminaries
than 7.6 m (25 ft).
The construction of low-bay luminaries is very similar to
These are not rigid rules. Conditions will often dictate that of high-bay luminaries except the reflectors, or
the use of high-bayor low-bay luminaries at mounting refractors, of the low-bay units are generally larger in
heights that vary from those indicated above. diameter than the high-bay units and the low-bay units
are usually fitted with a prismatic refractor cover on the
5.2.3.1 High-Bay Luminaries bottom of the luminaire. The refractor will oíten drop
down below the reflector to assure good distribution in
These luminaries generally use an HID lamp installed a wider pattern. While this will allow a wider spacing cri-
in a socket mounted below a ballast housed in some terion and better vertical illuminance, the potential for
form of metal enclosure. Lumen distribution is con- glare from the luminaire may increase. Often the larger
trolled by a reflector, or refractor, installed in such a diameter of these covers will permit light distribution
way that it captures most of the light emitted by the over an area great enough to lower the luminance of
lamp and directs it in a concentrated pattern down- the cover to a level acceptable to the occupants.
ward. The luminaire may have an enclosing plastic or
glass cover attached to the bottom of the reflector or There have been several successful installations in
refractor to enclose the lamp and to protect against high-bay applications where low-bay luminaries were
accidental damage. The cover may have a pattern of used to improve the vertical illuminanceof the tasks or
prisms to aid in the distribution of light from the lumi- to provide greater wall luminance, thereby improving
naire. The luminaire design will usually dictate the use the quality of the visual environment.
of either a clear or coated HID lamp, and the proper
lamp selection is critical to the success of the lighting 5.2.3.3 Other Luminaire Types
design. These luminaries may have an adjustable
socket mount to permit relocation of the lamp within Industrial luminaries are manufactured in various
the reflector or refractor. This will allow some field forms for special purposes. HID luminaries with pris-
adjustment of the luminaire distribution to meet spe- matic reflectors or full refractors are available to pro-
cific condition of the installation. Care must be exer- duce several distribution patterns: maximum distribu-
cised in positioning the lamp. The lamp socket must tion up, equal distribution up and down, or maximum
be securely locked into place to ensure the position distribution down. These can be used effectively in
will not change during normal luminaire operation. large spaces with light colored surface finishes to pro-
duce excellent vertical illuminance, good penetration
There are usually openings around the top of the into hard to light spaces within machinery, and a very
reflector to permit some of the light to be directed comfortable visual environment.
upward toward the ceiling. Where conditions warrant,
the luminaire may be gasketed to reduce the infiltra- Fiber optic luminaries and tubular guided illuminators
tion of air-borne contaminants. Several methods have are useful where light is necessary in spaces having
been developed to filter the air exchange between the hazardous atmospheres or in inaccessible locations.
inside of the luminaire and the room. This becomes The illuminators can be located in more easily acces-
more important if the luminaire operating cycle sible spaces and the light “piped into the hazardous
includes turning the luminaire off daily, which will spaces or the difficult to reach locations.
accentuate the effects of warming and cooling on this
air exchange.

Designers often recommend luminaire spacing that

provides a strong overlap in the light distribution pat-
tern to mitigate the effects of single lamp burnouts All discharge lamps, fluorescent or HID, have acces-
during the operating life of the system. Installing lumi- sory devices called ballasts for starting and stabilizing
naries having a spacing criterion of 1.0 in a pattern operation of the lamp. Detailed information should be
--``````-`-`,,`,,`,`,,`---

Copyright Illuminating Engineering Society of North America

18
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 ANSI / IESNA RP-7-01

obtained from the ballast manufacturersat the time of 6.1 .I Ballast Circuitry
project design because of the rapidly changing lamp
and ballast technology. Specific ballast issues associ- Four important characteristics of electronic ballast cir-
ated with industrial lighting that may arise in almost cuitry should be noted. These.are ballast factor, power .
every project are included here. factor, crest factor and total harmonic distortion (THD).

6.1 Fluorescent Ballast Issues Ballast factor provides a measure of the actual lamp
lumen output when operated by the individual ballast
Advances in solid-state, high frequency ballasts have in relation to the lumen output of the lamp when oper-
improved fluorescent system efficacy and, to some ated by a reference ballast. In other words, a percent
extent, luminaire light delivery efficiency through of the lumens generated in application versus the
improved performance of smaller diameter lamps. lumens listed in the lamp catalog.

Fluorescent lamp ballasts are available in a wide Power factor is a measure of how efficiently the bal-
array of choices. The choices for “straight‘! fluorescent last converts the voltage and current drawn from the
lamps include magnetic, electronic, instant start, rapid system to usable lamp power.
start and dimming ballasts. The following paragraphs
attempt to give guidance in the selection process to Lamp Current Crest factor, is a ratio of peak lamp cur-
designers, plant operating personnel and contractors. rent to the root mean square (RMS) lamp current. It is
Factors which may impact on the correct choice of flu- an indicator of the lamp current wave shape, and is
orescent lamp ballasts include environmental condi- generally required by lamp manufacturersto be I 1.7
tions, operating cycle, maintenance conditions, elec- in order to achieve rated lamp life.
trical power conditions and utility company require-
ments. It is often in the best interest of an end user to Total harmonic distortion (THD) is, in simplified terms, a
participate in ballast selection. measure of the amount by which the electric waveform
is distorted by harmonic currents flowing in the electric
Magnetic ballasts have provided the foundation for dis- power system lines. This distortion is generated, in
charge lamp operation since the first fluorescent and large part, by non-linear electrical loads in a facility. In
HID lamps were inventedin the middle of the 20th cen- NorthAmerica, the fundamental frequency is 60 Hz, the
tury. Electronic ballast development began in the second harmonic is 120 Hz, and the third harmonic is
1980s. Toward the middle of the 1990s, electronic bal- 180 Hz, and so forth. For practical purposes, the third
last technology advanced to the point where the origi- harmonic is usually the only one that will make a signif-
nal problems were overcome. The drive for improved icant contribution and most of the harmonic current in
energy utilization has fueled a rapid conversion to the the neutral of three-phase distribution systems is the
use of electronic ballasts in fluorescent luminaries.As third harmonic. This harmonic current will disturb utility
we move into the 2Istcentury, electronic ballastswill be power generation and, of more interest to the end-user,
the preferred fluorescent lamp operating accessory increase the current flowing in the neutral of three-
and it is likely their use will continue to increase. phase distribution systems and, possibly, cause it to
overheat and fail. Switching in modern solid-state elec-
Over the past several years, to assure proper operat- tronic ballasts can cause substantial line-current har-
ing characteristics for both the lamp and ballast, many monics when corrections are not implemented in the
fluorescent lamp manufacturers have either manufac- ballast. THD is, therefore, an important component of
tured their own ballasts or formed alliances with ballast the ballast operating effect. The American National
manufacturers to provide warranted lamphallast sys- Standards Institute (ANSI) requires electronic ballasts
tems with system performance guaranteed for some to have a THD of no more than 32 percent. Most elec-
period of years. It is important that the replacement tronic ballasts sold in North America have THDs in the
lamps used during the maintenance of these systems range of 5 to 30 percent and, therefore, should present
be the same as the lamps originally installed to main- no problems. There is a likelihood that electronic bal-
tain the warranted performance. If this can not be lasts with a THD of less than l O percent can cause high
assured, then any lamps substituted for the original inrush currents upon starting. Switching equipment
types must be evaluated prior to lamp replacement to installedon such circuits must be capable of withstand-
assure system performance will be maintained. The ing this current. All these ballast characteristics must be
system warranty may be voided by such replacement. carefully considered for each application.

It must be understood that the fluorescent lamp bal- Finally, it is important to be aware of the lamp holder
last market is in a constant state of development and (socket) configuration in luminaries using ballasts. A
it is suggested that manufacturer’s information be ref- reputable luminaire manufacturer will select the proper
erenced before a final ballast selection is made. lamp holder to perform properly with the ballast select-
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 ANSI / IESNA RP-7-01

ed. If a luminaire, originally supplied with Typical Industrial Areas in Which Average Sound Level
an instant start ballast, is to be refitted This Sound Level is Appropriate Ambient Noise Rating
with a rapid start ballast, the lamp holder Level of Interior
MUST be identified as suitable for the Offices, Control Rooms, Meeting 20-24 dE3 A
rapid start ballast, or the original lamp
holder should be replaced with a holder Warehouse or Storage Areas 25-30 dB B
suitable for use with a rapid start ballast. Shipping Dock, Equipment 31-36 dB C
Ballast manufacturers recommend the Rooms, Electrical Vaults, Large
use of knife-edge lamp holders when Parts Sub-Assembly
using electronic ballasts. High frequency Machine Shops, Foundries, 37 dB or More D
lamp currents require a better connection Printing Press Rooms,
than low frequency magnetic currents.

6.1.2 ElectromagneticBallasts
This can be an annoying and potentially dangerous
Magnetic ballasts are available in full and reduced characteristic in areas where there is moving machin-
lumen output in both standard and energy saving ery. If either of these conditions is a concern, elec-
types. The ballast must be compatible with the lamps tronic ballasts should be considered.
to be used in the installation.This sounds obvious, but
some energy saving lamps and ballasts will not oper- The US Department of Energy (DOE) Ballast Rule,
ate properly in combination. officially adopted in 2000, was designed to raise the
ballast efficacy for ballasts sold in new fluorescent
All indoor magnetic ballasts (except reactive types, luminaries by the year 2005, and as replacements in
which should seldom be used) should be Class P. existing luminaries by the year 2010. A likely result of
These ballasts have a thermally activated reclosing this legislationis rapid conversion of most common flu-
switch to protect the ballast from overtemperatureand orescent ballasts in North America to electronic types.
tampering and to meet the requirements of the
National Electrical Code (NEC) in the United States. 6.1.3 Electronic Ballasts
Electromagnetic ballasts, as well as all other types,
must be effectively grounded to meet code require- Many of the problems encountered with electromag-
ments. In areas where the ambient temperature may netic ballasts are overcome with electronic ballasts.
drop below 10°C (50"F), electromagnetic ballasts Along with their positive attributes, electronic ballasts
selected must be capable of starting and operating may also introduce a few problems.
the associated fluorescent lamps at the lowest ambi-
ent temperature expected in the space. Since electronic ballasts operate at a frequency of 20 to
50 kHz, they will not produce annoying flicker or poten-
By law, ballasts with PCB capacitors are no longer tially dangerous stroboscopic effects. The sound rating
permitted in North America. for most of these ballasts is "A" and any sound that is
generated is usually at a frequency that cannot be heard
Sound ratings for electromagnetic ballasts vary by humans. Electronic ballasts will operate most fluo-
depending on the type of lamps being operated. A bal- rescent lamps down to temperatures of -18°C (@ F).
last with the lowest available sound generating char-
acteristics should be selected. This becomes particu- In areas where infra-red control systems are used, the
larly important in locations where added sound from ballast operating frequency should be separated from
lamp ballasts may be distracting. In an office or quiet the operating frequencies of these controls, which typi-
location in the manufacturingfacility, the ballast sound cally operate in the band between 3042 kHz, to prevent
level should be " A where such a rating is available. ballast generated interference. (Most ballasts manufac-
Most T-12, T-1O, T-8 and smaller diameter lamps not tured today do operate above 40 kHz.)
over 1200 mm (48 in) long will operate on sound level Electronic ballasts are available in either instant start
" A ballasts. Higher power lamp ballasts will generate or some version of rapid start configuration.
more sound with 1500 ma, 2400 mm (96 in) lamp bal-
lasts having a sound rating of "D. Figure 9 indicates 6.1.4 Instant Start Ballasts
the various ambient sound levels in which the four rat-
ings should be used. Instant start ballasts are popular because they pro-
vide maximum energy savings and operate lamps in
Because they operate at the normal power system parallel, which means if one lamp fails, the balance of
frequency of 60 Hz, electromagnetic ballasts will be the lamps on that ballast will continue to operate.
more likely to produce flicker and stroboscopiceffects. Instant start ballasts may shotten lamp life in situa-
--``````-`-`,,`,,`,`,,`---

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 ANSI / IESNA RP-7-01

tions where the lamps are frequently switched on and and system compatibility be carried out before recom-
off. On circuits that have operating cycles of eight mending fluorescent dimming systems. It is also rec-
hours or more, lamp life is essentially the same when ommended that lamp warranty and performance infor-
using either instant start or rapid start ballasts. mation be checked with the lamp manufacturer for
lamps used with a particular dimming ballast. Multi-
6.1.5 Rapid Start Ballasts level switching is available using multiple ballasts in
each luminaire or a single ballast per luminaire
Rapid start lamp circuits are usually series-wired, arranged for two level control. Careful investigation is
which will extend lamp life for circuits switched often required before such a system can be employed.
but cause increased energy consumption compared
with instant start circuits. Therefore, a decision must 6.1.8 General Ballast Requirements
be made, based on the operating cycles of the
lamps, which wiring configuration best suits the indi- Figure 10 (see page 22) presents some of the elec-
vidual needs of the application. There are various tronic ballast considerations, and typical data, which
versions of the rapid start ballast circuit; for example must be evaluated before a final system decision is
rapid start, programmed rapid start or programmed- made. It is recommended that the specific numeric
start. Each has specific advantages and the char- values listed be checked against current practice and
acteristics of each should be considered in the equipment availability prior to purchasing.
choice of ballast to be used. Rapid start ballasts,
particularly the "program" modified circuits, will 6.2 High Intensity Discharge Ballast Issues
result in long lamp life regardless of the number of
switching cycles. Ballast Factor should be considered when selecting
HID luminaries. (See Section 6.1.1 .) The specific bal-
6.1.6 Compact Fluorescent Ballasts last factor of 0.9, 0.95 or occasionally 1.0 must be
used in the calculation process as it directly affects the
Much of the previous discussion of electronic ballasts initial and maintained light levels from the luminaries
also applies to compact fluorescent lamp (CFL) bal- under consideration.
lasts with the following additional comments.
All fluorescent and HID lamps exhibit negativevoltage
The CFLs chosen should have four-pin bases. Two- characteristics; that is, initially the impedance to the
pin CFLs are preheat lamps with starters and they are flow of current through the arc tube is high (before the
not suitable for use with electronic ballasts. arc is actually struck) and, as the arc is established in
the lamp, the impedance goes down. Because the
The electronic ballasts used with these lamps should impedance drops so dramatically with the striking of
have an end-of-life(EOL) circuit built into the ballast to the arc, an auxiliary device is required in the lamp cir-
reduce overheating of broken lamp cathodes and cuit to limit the flow of current through the circuit. This
minimizethe potential for lamps melting or cracking at device is the ballast. There are several circuit config-
end of life. urations for operating HID lamps. The power loss in
an HID ballast is generally in the range of 5-15 per-
A range of CFLs is available in self-contained, screw cent. HID lamp ballasts using the autotransformer
mount base configurations, which can, if space is type of voltage input have the advantage of wiring
available and other conditions of use are met, replace arrangements that allow a tapped primary. This will
incandescent lamps in many applications. permit the manufacturerto use one ballast production
Consultation with lamp and luminaire manufacturers model for several different system voltages. While this
is recommendedbefore these substitutionsare made. may be of limited value to a final user, it will probably
Note that power factor may be compromised in uni- reduce the cost of production and inventory for the
tized magnetic screw-base systems. ballast manufacturer and may translate to a lower
product cost. It may also be useful if the manufactur-
6.1.7 Dimming and Two-Level Switching Ballasts ing facility has several locations on the site, which
may have different voltages, because the tapped bal-
For additional energy savings, and where variable out- last primary would allow one replacement part to be
put fluorescent lighting is required, dimming and multi- used in several different plant locations.
level switching systems are available. Dimming ballasts
will dim from 100 percent light output to several lower This discussion will concentrate on those ballast cir-
levels, such as 50 percent, 10 percent or 1 percent of cuits that are most common in industrial lighting appli-
full light output. The cost and the compatibility of these cations. (See Figure 11.)
ballasts with various control systems varies, so it is rec-
ommended that a thorough investigation of the needs
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 ANSI / IESNA-RP-7-01

Ballast Ballast Characteristic Recommended Values - Unless m e r s

TYP are Specified by Lamp Manufacturer
(<=less than;>=greater than)
Electro- Sound Rating See Text
Magnetic Minimum Lamp Starting Temperature 10°C (50°F)
I
I Maximum Ballast Case Temperature
Standards Met I
90°C (194°F) at Hottest Spot
UL935; CANICSA-22.2 No 74-92 and
654; CBM; NEC; ANSIJEEE 82.1
Ballast Factor >85%
Power Factor >90%
Crest Factor 4.7
Total Harmonic distortion (THD) <20%
Number of Lamps Operated 1 or 2 (Vsdly)
Electronic Sound Rating < A (Usuaily Much Less)
Minimum OperatingFrequency 20,000 Hz
Minimum Lamp Starting Temperature - 1soc(0°F)
Standards Met ANSIAEEE C62.41; FCC Part 18
(EMIRFI); CBM; ÚL; CSA; NEC
Circuit Configuration Instant Start or Rapid Start
Ballast Factor >85% (May be lower for some lamps)
Power Factor >90%
Crest Factor 4.7
Total Harmonic distortion (THD) GO%
Number of Lamps Operated 1,2,3 or 4

Figure 11. Typical circuits for operating high intensity discharge lamps.

r - - - - _
r-------- 1 r-----
I 1 Core with
l I

I Capacitor
L. - - - - . - -. - - - - I
I \
I \
a a b a
II
IØ
'\
Voltage LJ
Lamp
Lamp
Line Lamp
Line Line
(a) High power factor reactor mercury lamp (b) High power factor autotransformer (c) Constant wattage autotransformer
ballast mercury lamp ballast ballast for mercury lamps or peak-lead
ballast for metal halide lamps

Series
line

Caoacitor I I
\ I

r - 1

I I
\ I
LJ
Lamp

(d) Constant wattage (isolated circuit) (e) Constantcurrent series regulatorballast

ballast for mercury lamps for mercury lamps

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22
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 ANSI / IESNA RP-7-01

6.2.1 Ignitors 6.2.3 High Pressure Sodium Ballasts

HPS lamp ballasts and pulse-start MH lamp ballasts HPS lamps show a rising voltage with rising lamp
differ from mercury vapor and most standard metal wattage. Because of this characteristic,maximum and
halide ballasts in that they contain an ignitor to provide minimum lamp voltage and wattage parameters have
the high voltage pulse required to start the lamp. The been established for HPS lamps (see Figure 12).
range of voltage pulses required to cold start HPS
lamps varies from 2.5 - 4.0 kV. Pulse start metal
halide lamps require about a 3 kV pulse for starting. Maximum lamp wattage
The pulse circuit is designed to turn off after the lamp
has successfully started by sensing the drop in open-
circuit lamp voltage.

Instant restarting of hot lamps can be accomplished

by increasing the ignition voltage. Voltage pulses of
10 - 70 kV are usually required to instantly restart a
hot lamp. In most cases, instant restarting is limited to
--``````-`-`,,`,,`,`,,`---

double-ended lamps because the increased voltage

may result in arc-over between the lead wires, sup- i
.
l
, .
i
ports or base contacts in single-ended lamps. A
I
1
I I I
I
I
I”
I
I
I
r
O 67 84 95101 122 140151
6.2.2 Metal Halide Ballasts Lamp voltage

The most common types of ballasts for MH lamps are Figure 12. Wattage and voltage limits for 400-W high
Lead-Peaked for lamps over 175 watts and Lag pressure sodium lamps-HPS “Trapezoid.”
Regulator (sometimes referred to as “HX or “HX-
H P F for high power factor ballasts) for lamps rated
less than 175 watts. Lead Peaked ballasts are very 6.2.3.1 Magnetic Regulator or Constant-Wattage
similar to Constant Wattage, Autotransformer (CWA) Autotransformer (CWA) Ballast
ballasts and, in fact, may be referred to as CWA bal-
lasts in some literature. These ballasts provide rela- CWA ballasts are probably the most common for HPS
tively good voltage regulation and, because they con- lamp operation and consist of a voltage regulating cir-
tain a capacitor in series with the lamp, offer good cuit that feeds a current limiting circuit and an ignitor
power factor characteristics. Where supply voltage pulse generator required to start the HPS lamp. CWA
regulation is good, it may be possible to use a high ballasts provide good wattage regulation over a range
power factor, reactor ballast which is usually less of input voltage changes and good regulation for
expensive than the more complex ballasts. changes in lamp wattage. This type is a higher cost
ballast than the reactor or lead circuit ballast and has
A lag-reactor ballast is essentially a metal core coil (the higher power losses, but the added costs can often be
reactor) in series with the lamp. As long as the electri- justified because of the better lamp performance. A
cal system voltage is within the range of the lamp open capacitor is usually included to provide good power
circuit voltage and voltage regulation of the source is factor correction.As with all auto transformer type bal-
good, these ballasts can be satisfactory and are sim- lasts, these may be suitable for use on a range of line
ple, small and inexpensive. The disadvantage is these voltage systems.
ballasts have a power factor in the range of 50 percent.
To improve the power factor, a capacitor can be added 6.2.3.2 Lag or Reactor Ballast
across the power leads, which will improve the power
factor to the range of 90-95 percent. These ballastsemploy a reactor in series with the lamp
designed to keep the operating characteristics of the
Pulse-start metal halide luminaries require a special lamp within the design trapezoid (see Figure 12). A
ballast with an ignitor, similar to those used in high starting ignitor is required and there is usually a power
pressure sodium ballasts. The ignitor is used to give factor correcting capacitor added across the line or the
the lamp the additional voltage “kick,” or pulse, it primaty transformer winding. These ballasts provide
requires to start quickly. These luminaries may be use- good wattage regulation for lamp voltage swings but
ful where it is necessary to have more rapid restart of poor regulation if the line voltage varies more than 5
the MH lamps following a voltage outage or when the percent. These ballasts are the least costly HPS bal-
luminaries are first turned on. (See Section 5.2.2.1 for lasts and have the lowest power losses.
more advantages of pulse-startmetal halide systems.)

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 ANSI / IESNA RP-7-01

6.2.3.3 Lead Circuit Ballast For applications of other, more specialized luminaries
These HPS ballasts have a combination of induc- in industry, refer to manufacturers’ publications that
tance and capacitance in the lamp circuit. They address those luminaries and applications.
decrease lamp current as the lamp voltage rises to
keep lamp operation within the trapezoid. These bal- 7.2 Operating Considerations
lasts provide wattage regulation for changes in both
lamp wattage and line voltage of no more than 1O per- Industrial luminaries must operate reliably in some-
cent. This ballast type is intermediate in cost and times hostile environments. It is rare in industry to find
power loss. locations where the space is conditioned and the
mounting is as uncomplicatedas recessed luminaries
6.2.4 Other HID Ballasts in a “tee-bar” ceiling. When those conditions do pre-
vail, the same luminaire installations found in offices
There are other types of HID ballasts available. will often work. In many locations in the modern fac-
Among them are dimming ballasts and two-level tory, there is minimal environmental control.
switching ballasts (to allow selecting between two Therefore, the luminaries must be capable of with-
lamp lumen outputs without extinguishing the lamp). standing the ambient environmentalconditions.
The designer should contact manufacturersfor further
information since the products available are develop- 7.2.1 Electrical
ing and the information changes rapidly.
The lighting specifier must know the electrical charac-
HID ballasts used in industrial lighting can be differen- teristics of the building to properly select the luminaire
tiated by their lamp wattage regulation capabilities. operating voltage. If incandescent lamps are used in
Dependingon the ballast type used, the lamp wattage any part of the building, it is necessary to provide a
can change as much as 2.5 percent.for each one per- voltage compatible with the lamps used. In the case of
cent change in line voltage. The best regulation bal- fluorescent or HID systems, where a ballast provides
lasts available maintain lamp wattage to within a the lamp voltage, the operating line voltage to the bal-
range of less than one percent for each one percent last is the designer’s critical consideration. The length
of line voltage change. of the wiring runs from the lighting panelboard to the
farthest luminaire on the circuit can impact voltage
HID lamps have poor lagging power factor, which can selection. Wire length and size must be matched to the
be expressed as relatively high line current for the circuit lighting load to ensure that the last luminaire on
power load involved. Generally, the presence of a the circuit will have suitable operating voltage. Voltage
power factor correction capacitor in the ballast circuit selection must also comply with the applicable electri-
solves this problem. Additionally, high pressure sodi- cal code requirements for maximum voltage to be
um systems, even with capacitors present, lose their used for luminaries at the prevailing mounting height.
power factor correction as the lamp ages. This is
because lamp impedance changes with age, while 7.3 Luminaire classifications
the ballast electrical characteristics remain the same.
Luminaries are complete lighting units connecting
--``````-`-`,,`,,`,`,,`---

For specific detailed information on all types, always lamp(s) and ballast(s) together with the parts
consult manufacturers’ ballast data. designed to distribute the light, to position and protect
the lamp, and to connect the lamps to the power sup-
ply. A common form of classification organizes lumi-
7.0 DISTRIBUTION MODES naries into three application areas: residential, com-
mercial and industrial. Within each application,
source, mounting and construction, e.g., high-bay
7.1 General Luminaire Characteristics and suspended metal halide lamp types, further classify
Performance luminaries. Another form of classification uses the
luminaire intensity distribution. Chapter 7 in the
Industrial lighting luminaries include a range of types, IESNA Lighting Handbook, 9th Edition, describes the
housing incandescent, fluorescent and HID light various classifications in detail. The International
sources. There are applications in industrial facilities Commission on Illumination (CIE) provides a classifi-
for all of the above and for other specialized lighting cation system based on the proportion of upward and
equipment such as light emitting diode (LED), fiber downward directed light output. This system is usual-
optic, stroboscopic luminaries and more. This docu- ly applied to indoor luminaries:
ment will investigate only those general lighting lumi-
naries commonly found in industrial environments, 0 Direct lighting - 90 to 100 percent of output
including luminaries using fluorescent and HID lamps. downward

24
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 ANSI / IESNA RP-7-01

0 Semidirect lighting - 60 to 90 percent of output Even gasketed luminaries, no matter how effec-
downward tive the gasket seal, have an exchange of air
General diffuse lighting - downward and upward between the ambient environment and the
components of light about equal inside of the luminaire. For particularly dirty
0 Semi-indirect lighting - 60 to 90 percent of out- areas, there are luminaries available that are fit-
put upward ted with various types of filters that allow the
Indirect lighting - 90 to 100 percent of output luminaire to “breathe” and still control the accu-
upward mulation of dirt and contaminants on the inner
surfaces of the luminaire. These luminaries
Most industrial applications require luminaries should be carefully evaluated for effectiveness
designed for a direct or semidirect light distribution. against the contaminated air in the application
Luminaries with an upward component of light, usually area in order to justify the added expense of “fil-
1O to 30 percent, are preferred for most areas, because tered luminaries.
lighting the ceiling or upper structure reduces lumi-
nance ratios between luminaries and the background. Direct LightingEquipment-Luminaries that direct 90 to
The upward light reduces the perception of glare from 100 percent of their lumen output downward form a
the luminaries, mitigates the “dungeon” effect of totally “direct” lighting system. Distributions of direct lighting
direct lighting, and creates a more comfortable and equipment vary from ‘hidespread to “highly concen-
cheerful environment. Industrial luminaries for fluores- trated.’’ The widespread distribution types include dif-
cent, HID and incandescent lamps are available with fuse and diffuse-specular white reflecting surfaces.
upward components. Good luminance relationships Aluminum, mirrored glass, prismatic glass, and other
can be achieved with direct lighting equipment if the illu- similar materials may be used to provide a wide distri-
minances and room surface reflectances are high and bution when the reflector is designed with the proper
if all components of the space have been carefully posi- contour. Also, this type of light distribution is advanta-
tioned (see Figure 13 (a) and (b), color insert). geous in industrial applications where mounting
heights are relatively low or where a large number of
Factors that lead to more comfortable and effective the visual tasks are vertical or nearly vertical. Highly
industrial lighting applications include: concentrated distributions are obtained with prismatic
glass, mirrored glass and aluminum reflectors. In addi-
Light-colored finishes on the outside of luminar- tion, this type of light distribution is useful where the
ies to reduce luminance ratios between the out- mounting height is approximately equal to, or greater
side of the luminaries and the inner reflecting than, the width of the room, or where tall machinery or
surface and light source. processing equipment necessitate directional control
for efficient illumination between the equipment. This
0 Higher mounting heights to raise luminaries out type of distribution produces relatively high horizontal
of the normal field of view. illuminance in proportion to the vertical illuminance,
and so may require the use of supplementary lighting
0 Better shielding of the light source by deeper when vertical illuminance is required on the visual task.
reflectors, cross baffles, louvers, or well-designed
diffusers. This is particularly important with high- In making a choice between widespread and highly
wattage incandescent or HID sources and very concentratedequipment on the basis of horizontal illu-
bright smaller-diameter fluorescent lamps. minance, a comparison of coefficients of utilizationand
spacing criteria for the actual room conditions serves
0 Selection of luminaries that contain specular or as a guide in selecting the most effective distribution.
--``````-`-`,,`,,`,`,,`---

non-specular aluminum or prismatic configured The coefficients of utilization should be based on the
glass or plastic for light control, so that luminaire best estimate of the actual ceiling, wall and floor
luminance in the viewing zone can be limited. reflectances as well as actual room proportions.
However, if it is desired to determine illuminances at a
0 Top and bottom openings in luminaries, which specific location or task orientation, then a point calcu-
generally minimize dirt collection on the reflector lation method should be used. This is particularly true
and lamp by allowing convective air circulation for luminaries at high mounting heights.
to move dirt particles upward, through, and out
the luminaire. Ventilated types of luminaries Other Types of Direct Lighting Equipment-Where a
have proved their ability to reduce maintenance low-brightness luminaire is required, a large-area Iow-
of fluorescent, HID and incandescent types of luminance luminaire should be used; for example a
luminaries. Gasketed, dust-tight and dirt- and diffusing panel placed on a standard type of fluores-
moisture-resistantluminaries are also effective cent reflector, an indirect light hood or a completely
in minimizing dirt collection on reflector surfaces. luminous ceiling.
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 ANSI / IESNA RP-7-01

Semidirect Lighting Equipment-This classification of

distribution is useful in industrial areas because the
upward component (1O to 40 percent) is particularly
effective in creating more comfortable seeing condi-
tions. A variety of fluorescent and HID luminaries with
this distribution are available and designed specifically
for industrial applications. While the semi-direct type of
distribution has a sufficient upward component to illu-
minate the ceiling, the downward component of 60 to
90 percent of the output contributes to good efficiency,
particularly where occasional ceiling obstructions may
lessen the effectiveness of the indirect component.

Industrial Applications of Other Distribution

Classifications-Thegeneral diffuse, semi-indirect,and
indirect systems are suitable for industrialapplications
where a superior quality of diffused, low-luminance
illumination is required and where environmentalcon-
ditions make such systems practical. An example of
such an application is the precision manufacturing
industry where there is a need for a completely con-
trolled environment including lighting and air condi-
tioning. Room suhace reflectances (initial and main-
tained) are important in the application of these light-
ing systems to ensure proper illuminance from the
system throughout its life. Figure 14. This plant has a variation in height
between high bay in the foreground and low bay at
the rear of the assembly area. (Photo courtesy of
Ruud Lighting.)
8.0 BUILDING CONSTRUCTION FEATURES THAT
INFLUENCE LUMINAIRE SELECTION AND LUMI- may require luminaries with narrow distributions.
NAIRE PLACEMENT Closely spaced high-bay luminaries are required
where the light is needed at or near floor level.

Mounting of luminaries must conform to the building Since the structure of the building is a convenient
structure. Industrial luminariesare usually designed to location for power distribution, the structural bay often
be mounted to the surface of the structure or sus- influences the luminaire pattern. This can either be in
pended by a hanging device. l h e skeletal framework terms of the spacing module of the main structure,

--``````-`-`,,`,,`,`,,`---
used in the construction of industrial buildings forms which sets a minimum spacing, or the secondary hor-
interior subspaces called bays. The selection of lumi- izontal members like purlins, which are used to sup-
naries, based upon their spacing criteria, is strongly port the power distribution system and may also
influenced by the height of the bay. For this reason, establish a set quantity of luminaries in each bay.
industrial buildings are described as having low-bay Either way, the luminaire spacing may be determined
and high-bay areas (see Figure 14). by the structure. It is common to adjust the number of
luminaries installed in a space to allow for a some-
Many modern industrial assembly buildings involve what regular luminaire pattern that will complimentthe
steel member construction with an outer shell or “tilt- structural building array. This approach is practical as
up” concrete wall construction. The economies of this long as the adjustment in the number of installed lumi-
kind of project generally require a single floor building naries does not vary from the number required to
(and maybe a mezzanine) spread out generously achieve the designed illuminance, light distribution
over the site. This type of building may have a mixture and lighting quality by more than 1O percent. Lighting
\
of high-bay and low-bay areas. designers, then, must fine-tune their designs with
respect to the target illuminance levels.
There are certain types of structures, particularly in
metals material producing and fabrication (stamping Luminaries that are properly designed to operate
and forging), where large machines and overhead under the expected shock conditions should be
cranes are involved and where mounting heights can installed in building locations where there is a proba-
often exceed 15m (50 ft). l h e combination of low bility of high levels of vibration. The luminaire mount-
room cavity ratios and dirty environmental conditions ing must be carefully designed to accommodate the
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26
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 ANSI / IESNA RP-7-01

vibration. Accessories that are useful for these appli- sis is adequate is to answer the question “what is the
cations include spring mounting devices, lamp retain- cost of a wrong answer?“
ers to prevent lamps from vibrating out of the lamp
holders, and safety chains to prevent the luminaire Probably the most common type of first-level analysis
from vibrating loose and falling to the floor. is the “Simple Payback” method. This method is
designed to answer the question “how long will it take
to recover the initial lighting system cost?” This is
9.0 LIGHTING SYSTEM ECONOMIC ANALYSIS’ determined in the simple payback method by the for-
mula:
Equation 1
Good lighting must be responsive to the needs of the
owner. Lighting systems must provide a lighted envi- simple payback = incrementalinvestment
ronment that allows workers to perform at the highest incrementalannual cash flow
possible level, satisfy the aesthetic needs of the occu- In this equation, the “incremental investment” is the
pants, and must operate economically. “Economical” difference in the first (or installed) cost of the two sys-
should not be confused with “cheap” or even “lowest tems, which are being compared. The “incremental
first cost.” The lighting system that providesthe lowest annual cash flow” is the difference in the cost of ener-
installed cost may result in poor worker performance, gy and maintenance (including lamp replacement,
which leads to unacceptably high labor costs. Or, it energy cost, repair or replacement parts and the labor
may not provide a lighted environment to allow the to accomplish the maintenance) for the two systems
workers to perform at a level that will allow the com- that are being compared. The method can be used to
pany to be as profitable as it should be. An economi- compare an existing system with a potential replace-
cal lighting system is one which, when the first cost, ment system or two systems that are being consid-
operating cost, and system performance are all con- ered for a new installation. In addition, the method
sidered, provides the greatest practical benefits for may also be used to compare more than two systems
the least total cost. This description of economical is but that may lead to even wider variance of results. A
often termed “cost-effective.” simple payback result is shown in Figure 15.

The IESNA considers economic analysis to be a two Ali first-level economic analysis, such as the simple
level process. First-level provides a quick and inex- payback method, suffer from a lack of considerationof
pensive means of determining the costs of two, or many important elements of a complete analysis. The
more, lighting systems, relative to each other. While cost of money and equipment lifetimes need to be
the cost to provide a first-level analysis may be low, considered for a complete economic analysis.
the results are more subject to error than a more com-
plete analysis would be and the longer the time frame There are other first-level methods of analysis avail-
under consideration in the study, the greater the able if such a study will provide the necessary infor-
potential for error. Second-level economic studies mation. Simple Rate ofßeturn is the inverse of Simple
take into consideration many more conditions than Payback, giving a simplified rate of return for the sys-
first cost, such as operating cost, maintenance, and tems with the lower total costs. However, it suffers
time cost of money. These also require a great deal from the same problems of the Simple Payback
more time to complete. The first decision that must be method. The popular Cost of Light considers the cost
made is the level of confidence required and the per lumen for two different lighting systems by com-
acceptable study cost for the numbers coming out of paring the owning and operating costs for each.
the economic analysis.
All of these systems have shortcomings if the real
After this has been determined, the study level can be need is a complete economic analysis. The better
established. solution, if more exact data is required, is to run a sec-
ond-level analysis that will include many of the critical
First-LevelAnalysis: First-level analysis requires rela- elements not included in the first-level analysis.
tively simple calculations that can usually be per-
formed by “hand calculation methods and do not Second-LevelAnalysis: The distinguishing feature of
require the use of a computer program. Because all second-level economic analysis methods is the
these methods do not take into considerationthe time inclusion of the time value of money. Additionally,
value of money and do not usually provide the means these methods allow extending the period of the
to evaluate various maintenanceand operating condi- analysis over many more years than is possible with
tions, they yield only crude numbers, which may be a first-level analysis, often considering the costs for
valid for only a short time after the initial installation is periods of twenty years. If a second-level analysis is
completed. One way to determine if a first-level analy- required, quite often the end user’s financial depart-
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Systems Initial Incremental Additional Annual Simple

Investment Change Annualized System Payback
(in $000) (in $000) costs Savings (in years)
(in $000) (in $000)
Base System 110 NIA 20 NIA NIA
Alternate Sys. 1 120 10 17 3 3.33
Alternate Sys. 2 130 . 20 13 7 2.86
--``````-`-`,,`,,`,`,,`---

Alternate Sys. 3 140 30 21 -1 No

Payback

Where the following definitions apply:

Column Heading Information Contained in Column

System A listing of the number and description of each of the systems to be compared

Initial Investment The initial installed cost of each of the installed systems in thousands of
dollars ($000)

Incremental Change Incrementalchange in the initial installed cost of the alternate systems vs. the
from Base (in $000) base system

Additional Annualized The annual cost of operating and maintaining the system (energy, lamps,
Cost (in $000) repairs, labor, etc.)

Annual Savings The difference between the annualized cost of the base system and the
(in $000) annualized cost of each of the alternate systems (minus sign {-} indicates
alternate system costs more /year to operate than base system)

Simple Payback . The number of years it will take to return the initial added investment in each
(in years) of the alternate systems

Note that Alternate System 3 will never pay back the added initial investment cost because it costs more to
operate Alternate 3 than it does the Base System.

ment or advisor will determine the calculation proce- A decision must then be made as to whether the study
dure and values to be used. The information in this should be performed in terms of present value or
section is provided to give the reader a general future value and an interest rate (or “opportunity “ rate,
overview of the information that may be required for a term often used by financial professionals) must be
second-level economic studies. selected. The cost is usually provided in consultation
with the owner’s financial advisors.
The lighting and associated mechanical system infor-
mation required to perform a second-level analysis is There are many methods that the second-level eco-
more comprehensive than required for first-level analy- nomic analysis may take - Saving Investment Ratio,
sis. The information required for second-levelanalysis Internal Rate of Return, Net Present Value or, the
may include the following (see box top of next page): most common method, Life Cycle Cost/Benefit
Analysis. The actual method of economic analysis
In addition to these considerations, there are system must be determined between the lighting system
costs associated with environmental issues such as designer and the financial advisors. The calculation
hazardous waste disposal in the lighting system com- method for second-level economic analysis is beyond
ponents that must be considered. the scope of this Recommended Practice but further
information is available from IESNA in the document
Once all of the necessary information has been gath- RP-31-96, Recommended Practice for the Economic
ered, the costs can be converted to equivalent annu- Analysis of Lighting.‘
al costs for each of the systems under consideration.

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Initial System Costs Owning and Operating Costs

Lighting system material and labor cost Lighting system energy costs
Total lighting system power wiring cost Air conditioning energy costs
Air conditioningto dissipate heat from lighting system (Tons) Lighting system maintenance costs (lamps, ballasts, labor
to replace & clean, etc.)
1st cost of air conditioning equipment Air conditioning operating costs
Reduction in cost of heating equipment due to heat from Heating system operating costs
lighting system
Utility incentives (reduced cost due to energy efficient Other annual costs
lighting)
Other first costs Annual insurance costs
Sales tax on equipment purchase Annual property taxes on equipment
Salvage value of lighting system at end-of-life Income tax effect (due to depreciation of equipment)

(Division 1). The ‘7-number” of the lighting equipment

10.0 SPECIAL CONSIDERATION FACTORS must always be less than the “flash point temperature”
of the hazardous material in the area.
10.1 Lighting and Space Conditioning Hazardous Gas Not Normally Present (Class 1,
Division 2)
The heat from lighting equipment is heat that is added If the gaseous material is not normally present
to the normal space heating. For some manufacturing (Division 2), the limiting temperature is internal to the
spaces, this heat must be considered as part of the luminaire, usually the lamp envelope hot spot.
cooling load. By using the lighting system as a return
air path, or returningair from locations where the light- Hazardous Dust Normally Present (Class 2, Division
ing is located, lighting heat can be exhausted before it 1); Hazardous Dust Not Normally Present (Class 2,
affects cooling. Whether this happens as described Division 2), and Fibers and Flyings (Class 3, Division
depends on the type of HVAC system and how the 1 and2)
particular space is heated and cooled. Conversely, The limiting temperature is on the exterior of the lumi-
lighting heat can be used for comfort heating in loca- naire.
tions where it is required.
A third party, such as an independent testing laborato-
10.2 ClassifiedAreas ry, usually “lists” a specific luminaire as being suitable
for classified environment and allows the luminaire
Classified Areas are where flammable gas or vapors manufacturer to apply a label indicating suitability.
or combustible dust or easily ignitable flyings or fibers Typically these are large red labels. The two most com-
are or can be present. (See Figure 16, color insert.) mon mistakes in classified lighting applications are:
These are defined in the National Electric Code
(NEC) in the United States in terms of Classes (gas, 1. An area is defined incorrectly as being “hazardous”
dust) and Divisions, which define the conditions and or a specific luminaire or rating is erroneously
manner in which the material is present. The National declared suitable for a specifically rated area.
Fire Protection Association (NFPA) defines the haz- 2. An applied luminaire rating has critical tempera-
ardous nature of the space and the requirementsfor tures that are too high with regard to the auto-igni-
luminaries suitable for application in classified areas. tion temperature of the hazardous material or rating
The designer should check with the insurance carrier category present.
for the industrial site to determine the exact Class and
Division for individual areas. The classified label may say that it is suitable for
Class I, Division 2 applications. But it is the tempera-
ture for each wattage rating that determines whether
Hazardous Gas Normally Present (Class 1, Division 1)
that luminaire can be applied based on the auto-igni-
A considerable focus is placed on external or internal
tion temperature of the substance present.
temperatures, or ‘7-number” of the luminaire. Internal
temperature is usually the hot spot temperature of the
The typical Class 1, Division 1 luminaire has a ballast
lamp envelope. In the case of hazardous gases, the
compartment and a heat resistant tempered glass lamp
limiting temperature is on the exterior luminaire sur-
enclosure. Configuredthis way the luminaire has almost
face if the hazardous material is normally present “in
the same optical characteristics as the bare lamp.
quantities cuff icient to produce ignitable mixtures”
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Utilization can be materially improved with classified 10.5 Low Ambient Temperatures
location luminaries by using optical refractors or extemal
reflector accessories available from the manufacturer. Abnormally low ambient temperatures are usually
found in commercial food processing and distribution
10.3 High Humidity or Corrosive Atmospheres facilities. Temperatures become an issue if they are
below 10" C (50°F) for fluorescent lamps, and -29" C
High humidity or corrosive atmospheres are likely to be (-20" F) for HID lamps. Fluorescentsystems general-
present in at least some areas in a typical plant. Further, ly require a ballast for low temperature starting if the
outdoor lighting locations may be exposed to rain, snow, ambient temperature is lower than 10" C (50" F) for
fog, wind, high humidity and salt-laden sea air. standard lamps and -18" C (Oo F) for 800 ma and
1500 ma lamps. At temperatures less than 20" C (68"
The usual methods to protect against these atmos- F) fluorescent lamps stabilize at rated watts but at less
pheres include the use of materials that resist corro- than rated lumens. Enclosingthe bulb-wall, either with
sion, special surface preparationsand corrosion resis- a plastic sleeve or an enclosed optical area, will
tant coatings or paint such as epoxy, polyester or improve the lumen output. Depending on the type of
polyvinyl chloride. In addition, robust modes of paint enclosure and the ambient conditions, the lamp or
application such as electro-static coating or powder lamps may heat up the enclosure to normal operating
coating may be used. Luminaries that have non-metal- temperature to produce rated lamp lumens.
lic outer housings are also available. Some luminaries
for classified locations are constructed in a manner Most ignitor-start HID ballasts are rated to start a lamp
that makes them suitable for high-corrosionareas. (pulse-start metal halide or high pressure sodium) in
temperatures to -40"C (-40°F). Temperatures below
In the future, fiber-optics-basedsystems may find more this require auxiliary incandescent sources, which warm
application in classified and high corrosive areas up the interior of the luminaire until the HID lamp starts.
because both the heat source and the material subject to These are usually coupled with a relay, which tums off
corrosive attack are effectively removed from the space. the incandescent source when the HID lamp starts.

10.4 High Ambient Temperatures 10.6 Clean Rooms

Abnormally high ambient temperatures are often pre- Clean room lighting uses entirely different luminaries
sent in industrial applications, especially near the ceil- than other industrial environments. Clean rooms are
ing where the luminaries are installed. Industrial lumi- sealed, controlled environmentsdesigned to eliminate
naries are available with ratings for ambient tempera- microscopic particles of a specified size. The particle
ture conditionsof 40" C, 55" C and 65" C (104" F, 131" may be dirt, which at a certain size (usually measured
F, 149" F). The temperature rating of the selected lumi- in microns) causes quality problems of the manufac-
naire is important and should be at least as high as the tured product, such as a silicon chip. The particle
temperature in which it is to operate during the could also be an organism, such as a microbe that
warmest season of the year. The limiting factor can be must be eliminated from an operating room. The
any of several components within the luminaire. If the Institute of Environmental Sciences (IES) categorizes
limiter is a ballast component, the ballast housing may generic clean rooms by a series of classifications
often be remotely mounted in a cooler location. based upon the number of micron particles found in a
cubic foot of air inside the room. The categories start
Except for ignitor-start lamps (high pressure sodium at 100,000 parts per cubic foot and get cleaner by fac-
and pulse-start metal halide), the only distance limita- tors of ten. Class 10,000, class 1,000, class 1O0 and
tion to remote ballast location is the wire gauge. This class 10 Clean Rooms are all defined by this organi-
is sized for the distance, according to the ballast man- zation. Quite often, class 100 clean rooms are found
ufacturer's recommendation, to hold voltage drops to inside class 1.000 clean rooms.
a comfortable minimum.
Clean room structure usually includest-grid ceilings of
With any system that has a pulse-igniter, the maximum a type not found outside this application. The t-grid is'
distance the ignitor can be removed from the lamp is of a larger cross-section, such as 1 ?" or 2 wide and
limited. In some cases the igniter can be placed in a is always gasketed in some fashion. Many of these
compartment that has suitable heat sinking and ceilings are made for walking upon so that the fixtures
remain with the optical portion of the luminaire (the and High Efficiency Particulate Air (HEPA) filters can
other heat-sensitive components can be mounted be serviced from above.
remotely). Otherwise, a "long range ignitor" should be
used to increase the remote distance. The ballast There are four main types of luminaries used in clean-
manufacturer should be consultedfor exact limitations. rooms:
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Gasketed recessed (troffer) fluorescent level. There may be perceptible differences in illumi-
Tear-drop surface fluorescent nance if suggested spacing criteria values are
Flow-thru recessed fluorescent exceeded. Recommended luminaire spacings can be
Recessed T5 fluorescent integral to the T-grid determinedfrom publishedspacing criteria. When cal-
culating values such as uniformity and average light
Gasketed recessed fluorescent luminaries are usual- levels for general lighting the grid spacings should be
ly used in the class 100,000 and class 10,000 spaces, sufficiently small to give accurate values.
and the other three types are used as more and more
of the grid-spacesare taken up with filters and cannot Production functions situated close to walls should
be occupied with luminaries. have a general illuminance comparable to that in the
central area. The distance between the wall and the
In most of these construction styles, the important adjacent luminaries should not exceed one-half the
issues are that gasketing seals the room from the out- spacing between those in the central area. Closer
side environment and that the outside surfaces are spacing is often preferred.
smooth and cleanable. Prismatic lenses, for example
normally are installed “prisms-up”to present a smooth General lighting defined by the building structure may
surface to the space. not be adequate for some difficult visual tasks or situ-
ations where there are obstructions. Here, supple-
10.7 Food and Drug Processing mentary task lighting may be necessary.

Food and drug processingareas generally have addi- One design approach is to provide general lighting for
tional requirements for construction and materials circulation, safety or simple visual tasks, with the addi-
used in the luminaire. The requirements are docu- tion of supplementary lighting directly adjacent to an
mented by sanitation-regulatingentities, such as the assembly line, workbench or inspection area.
National Sanitary Foundation (NSF) or the US
Department of Agriculture (USDA), and can classify
different sections of the food processing area by the 12.0 SUPPLEMENTARY TASK LIGHTING
proximity of the luminaire to the food. Some classifi-
cations call for smooth exterior surfaces to eliminate
areas for particle accumulation or bacterial growth. Difficult visual tasks, such as inspection, often require
One constant is that glass cannot be exposed. This a specific quality and quantity of light that cannot read-
means that open-lamp and glass-enclosed luminaries ily be obtained by general lighting methods.
are not suitable. In many food processing areas, Supplementary luminaries are often used to:
scheduled pressure washing is required and therefore
luminaries must be gasketed to withstand washing. o provide higher illuminances
Each facility’s pressure washing equipment is differ- o direct attention on small or restricted areas
ent, producing different pressure and flow rates. This o achieve a certain luminance
information should be obtained from the plant engi- o provide a specific color rendition
neering office and luminairecapabilities matched to it. o permit special aiming or positioning of light
Paint is required to be non-toxic and environmentally sources to produce/avoid highlights or shadows
neutral, in case it chips or flakes off. Unfinished stain- o reveal the details of the visual task.
less steel luminaries are popular in the extremes of
this type of application. The specific requirement of each visual task need to
be evaluated before supplementary task lighting can
The color rendering propertiesof light sources used in be specified. Simply adding lighting at the task with no
food inspection areas are important when examina- consideration for the light reflecting or transmitting
tion is based on color appearance. (See Section 3.8.) characteristics of the object(s) observed will be inef-
fective. An improvement in the visibility of the task will
depend upon improvement of one or more of the four
11.O GENERAL LIGHTING fundamental visibility factors - luminance, contrast
(chromatic or achromatic), size and time.

General lighting is intended to provide substantially The planning of supplementary task lighting also
uniform illumination throughout an area, exclusive of requires consideration of the visual comfort of work-
any provision for special local requirements. Uniform ers performing the task and other workers in the
illuminance is the distribution of light such that the immediate area. Supplementary equipment must be
maximum and minimum illuminance at any point is carefully shielded to prevent glare for the user and
not more than one-sixth above or below the average neighboring workers. Luminance ratios should be
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carefully controlled. Ratios between task and imme-

diate surroundings should be limited, as recom-
mended in Figure 2. To attain these ratios it is nec-
essary to coordinate the design of supplementary
task lighting and general lighting. (See Figure 17 (a)
and (b).)

12.1 Luminaries for Supplementary Task Lighting

Supplementarytask lighting luminariescan be divided

into five major types according to candlepower distri-
bution, luminance and other construction features. A
graphic representation of the different types of sup-
plementary lighting is shown in Figure 18.

Figure 18. Typical configurations of supplementary

lighting luminaire types.

Type S-l- Directional. Includes all concentrating lumi-

naries. Examples are reflector or narrow-beam spot
lamps Or units that employ concentrating or colhat- Figure 17. (a) A combination of general and task light-
ing reflectors or lenses. Also included in the group are ing provides uniform illuminance for assembly of elec-
concentrating linear units such as a well-shieldedflu- tronic Printers. (Photo Courtesy of Genlytmhomas.)
orescent lamp within a concentrating reflector or lens,
or both.

Type S-Il - Spread, High-Luminance. Includes

small-area sources, such as incandescent, tungsten-
halogen or high-intensity discharge. An open-bottom
luminaire that has a deep-bowl reflector with a diffuse
reflecting surface is an example of this type.

Type S-Ill - Spread, Moderate-Luminance. Includes all

fluorescent luminaries having a variance in luminance
greater than 2:l across the light-emittingsurface.

-
Type S-IV Unifonn-Luminance. Includes all lighting
units having less than 2:l luminance variance across
the light-emitting surface. Usually this luminance is less
than 6800 cd/m2.An example of this type is a group of
fluorescent lamps behind a diffusing panel, or con- Figure 17. (b) and for computer workstations in a pro-
cealed fluorescent lamps producing a linear arrange- duction area (Photo courtesy of Hubbell Lighting.)
ment of reflected light on a diffuse reflective surface.
--``````-`-`,,`,,`,`,,`---
afier assembly. Portable equipment, however, can be
Type S-V - Uniform-Luminancewith Pattern. Includes used.to good advantage where it must be moved in
all units described in Type S-IV except that a pattern and around movable machines or objects, as in air-
of stripes is superimposed over the lighted image. An plane assembly, or in maintenance operations where
example of this is a group of bare fluorescent lamps, internal surfaces must be viewed. (See Figure 19.)
arranged in a regular, directional spacing, with a black The luminaries must be mechanically and electrically
background or non-reflective surface between the rugged to withstand possible rough handling. Lamps
lamps. This unit is used to project a precise series of should be guarded and of the rough-service type.
high-contrast lines across the surface of the task or Guards or other means should protect the user from
the object being inspected. excessive heat. Precautions, such as the use of
ground fault circuit interrupters for personnel protec-
12.2 Portable Luminaries tion, should be taken to prevent electrical shock, and
electrical connections must be suitable for the service
Wherever possible, supplementary luminaries should to which they will be subjected.
be permanently mounted in the location where they
can produce the best lighting effect and maintenance
32
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 ANSI / IESNA RP-7-01

Figure 30.
Storage of
materials in
the center
floor area of a
production
facility.
(Photo
--``````-`-`,,`,,`,`,,`---

courtesy of
Holophane.)

Fiaure 32. Aimable floodlight luminaries. (Photo courtesy of Ruud Lighting.)

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 ANSI / IESNA RP-7-01

Figure 13 (a) and (b).

Light colored surfaces
ensure good lumi-
nance relationships.

Figure 13(a) (Photo courtesy of Holophane.)

Figure 13b
(Photo
courtesy
of Hubbell
Lighting.)

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II
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Figure 16. Dust-tight luminaries on an outdoor crane assembly.

(Photo courtesy of Phoenix Products Company, Inc.)

Figure 23.
Uniform lighting
is provided for
horizontal work
surfaces in a
packaging area.
(Photo courtesy
Holophane.)

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Figure 24.
Luminaries
located over
the floor
storage area
provide
horizontal
illuminance for
identification
of product to
be shipped,
while
luminaries
close to the
door openings
provide light
for loading
trailers.
(Photo
courtesy of

--``````-`-`,,`,,`,`,,`---
Holophane.)

Figure 29. Careful

placement of overhead
luminaries and a built-in
shield over the LCD
display insure that there
are no reflections on the
tilted control panel. (Phc
courtesy of Holophane.)

IV
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13.2 InspectionTechniques

The color of light can be used to increase contrast by

either intensifying or subduing certain colors inherent
in the seeing task. To intensify a color, the light source
should be strong in that color; to subdue a color the
source should have relatively low spectral power in
that color. For example, it has been found that using a
bluish light such as a daylight fluorescent lamp can
emphasize imperfections in chromium plating over
nickel plating.

Three-dimensional objects are seen in their apparent

Figure 19. Small portable luminaries provide local- shapes because of the shadows and highlights result-
ized lighting on the task. ing from a strong directional component in the incident
light. This directional effect is particularly useful in
12.3 Classification of Visual Tasks and Lighting emphasizingtexture and defects on uneven surfaces.
Techniques

--``````-`-`,,`,,`,`,,`---
(See Figure 21 .)
Figure 21.
Visual tasks requiring supplementary lighting are Directional
unlimited in number but can be classified according lighting
to certain common characteristics. The detail to be (right)
seen in each task group can be emphasized by the reveals a
application of certain lighting fundamentals. Figure pulled
thread
20 classifies tasks according to their physical and unseen by
light controlling characteristics and suggests lighting diffuse
techniques for good visual perception. It should be lighting
noted when using Figure 20 that the classification (left.)
of a visual task is based on the task?scharacteris-
tics and not on its application. For example, on a
drill press, the visual task is often the discernment
of a punch mark on metal. This could be a specular
detail with a diffuse, dark background, classification
A-3 (b) in Figure 20. Luminaire types S-Il or S-Ill
are recommended. S-Il on an adjustable arm brack-
et may be a practical recommendation when space
is limited. Several luminaire types are applicable for
many visual task classifications, and the best lumi-
naire for a particular job will depend upon physical
limitations, possible locations of luminaries and the
size of the task to be illuminated. Silhouette is an effective means of checking contour
with a standard template. Illumination behind the tem-
~~ ~ ~~~~~~
plate will show brightness where there is a difference
13.0 SPECIAL EFFECTS AND TECHNIQUES between the contour of the standard and the object to
be checked.

13.1 Color Contrast Fluorescence under ultraviolet radiation is often use-

ful in creating contrast. Surface flaws in metal and
Color as a part of the seeing task can be effectively nonporous plastic and ceramic parts can be detected
used to improve contrast. While black and white may by the use of fluorescent materials.
be the most desirable combinations for continual
tasks such as reading a book, it has been found that The detection of internal strains in glass, lenses, lamp
certain color combinations have a greater attention bulbs and transparent plastics may be facilitated by
value. Black on yellow provides the maximum visual transmitted polarized light. The nonuniform spectral
contrast; and the next combinations in order of prefer- transmittance of strained areas causes the formation of
ence are green on white, red on white, blue on white, color fringes that are visible to an inspector. With trans-
white on blue, and, finally, black on white. parent models of structures and machine parts, it is
possible to analyze strains under operating conditions.

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Figure 20. Classification of Visual Tasks and Lighting Techniques.

Classification of Example Lighting Technique

Visual Task

General Description Lighting Requirements Luminaire Type Luminaire Location

Characteristics

PART I-FLAT SURFACES

~~~

A.-OPAQUE MATERIAL

1. DIFFUSE DETAILAND BACKGROUND

--``````-`-`,,`,,`,`,,`---

a. Unbroken surface Proofreading printed text Prevent direct glare and S-Il or S-Ill At 45" to page, opposite
shadows viewer
b. Broken surface Scratch on unglazed title Emphasize surface breaks S-l At grazing angle to surface

2. SPECULAR DETAILAND BACKGROUND

a. Unbroken surfaces Dents, warps, uneven Emphasize uneven surface s-v So image of sourceipattern
surfaces is reflected to viewer
b. Broken surface Scratch, scribe, engraving, Create contrast of cut edge S-Ill or S-IV when not Source/pattern is reflected
punch marks against specular surface practical to reorient task to viewer and edge or
mark
is dark
c. Specular coating Inspection of finish plating Emphasize unplated surfaces S-IV with color of source To reflect large, diffuse source
over specular over specular base selected to create image toward viewer
background material maximum color contrast
between two coatings

3. COMBINED SPECULAR AND DIFFUSE SURFACES

a. Specular detail on Reflective varnish or foil Produce maximum contrast S-Ill or S-IV Off-center so image of
diffuse, light applique on matte paper without veiling reflections source does not reflect
background stock directly
b. Specular detail on Punch or scribe marks on Create uniform, bright reflection S-Il or S-Ill So that light reflects from
diffuse, dark dull or dyed metal on detail detail
background
c. Diffuse detail on Graduation marks on a Create uniform, low-brightness S-lll or S-IV So that image of source is
specular light steel scale; reverse print reflections in specular reflected toward viewer
background on a glossy stock background
d. Diffuse detail on Soapstone marks on black Produce high-brightness detail S-Il or 5-111 So that image of source is
specular dark paint against dark background not reflected into view
background

B. TRANSLUCENT MATERIAL

a. With diffuse surface Frostedetched glass or Visibility of surface detail S-Il or S-Ill Treat as opaque, diffuse
plastic, lightweight surface (see A.l)
fabrics, hosiery
Visibility of detail within the S-l or S-IV Backlight through material
material (see Fig. 19-15f and n)
b. With specular Scratch on opal glass or Visibility of surface detail Treat as opaque, specular
surface plastic (see A.2)
Visibility of detail within the S-Il, S-ill, or S-IV Backlight through material
material (see Fig. 19-15f and n)

C.TRANCPARENT MATERIAL

Clear material with Plate glass; plastic To produce visibility of details S-V and S-I Transparent materials should
specular surface glazing sheet within the material, such as move in front of Type S-V
bubbles and details on the then in front of black
surface, or scratches backgroundwith Type S-l
and waviness directed to prevent
reflected glare

34
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Figure 20 Continued

Classification of Example Lighting Technique

Visual Task
~

General Description Lighting Requirements Luminaire Type Luminaire Location

Characteristics

D. TRANSPARENT OVER OPAQUE MATERIAL

a. Transparent ma- Instrument panel Visibility of pointer and scale S-I So reflection of source does
terial over diffuse without veiling reflections not coincide with the angle
background from the scale background of view (see Fig 19-150)
or cover
Varnished desk top Visibility of detail on or in S-IV So that image of source and
the transparent coating or pattern is not reflected to
on the opaque base the eye (see Fig. 19-15)
material
Emphasize uneven surface
b. Transparent ma- Glass mirror Visibility of detail on or in S-l So reflection of source does
terial over specular transparent material not coincide with the angle
background of view the mirror should
reflect a black background
Visibility of detail on specular S-IV So that image of source and
background pattern is reflected to the
eye (see Fig. 19-151)
~

PART Il-THREE-DIMENSIONAL OBJECTS

A. OPAQUE MATERIAL

1. Diffuse detail and Dirt, checking, cold-flow or To emphasize detail having S-Ill or S-Il (standard To prevent direct glare and
background blow-holes in castings poor contrast source) shadows (see Fig.
19-15h)
"Black-light" source when To direct ultraviolet
object has a fluorescent radiation to all surfaces
coating to be inspected
S-l (standard source) To emphasize detail by
means of highlight and
shadow (see Fig. 19-150)

2. Specular detail and background

a. Detail on the Dent on silverware or To emphasize surface s-v To reflect image of source to
surface chrome variation eye (see Fig. 19-159)
Inspection of finish plating To show areas not properly S-V plus proper selection To reflect image of source to
over underplating plated of color eye (see Fig. 19-159)
b. Detail in the Scratch on watch case To emphasize surface break S-IV To reflect image of source to
surface eye (see Fig. 19-15m)

3. Combination Specular and diffuse

a. Specular detail on Scribe marking on casting To make line reflect light over S-Ill or S-Il Adjust in relation to task for
diffuse background dull background best visibility (adjustable
luminaire required)
Overhead to reflect image of
source to.eye (see Fig.
19-15j)
b. Diffuse detail on Micrometer scale To create luminous back- S-IV or S-Ill Position with axis normal to
specular ground against which dark axis of micrometer
background scale markings are in high
contrast
Coal picking To make coal glitter in S-l or S-Il To prevent direct glare
contrast to dull
impurities

--``````-`-`,,`,,`,`,,`---

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Figure 20 Continued
Classification of Example Lighting Technique
Visual Task

General Description Lighting Requirements Luminaire Type Luminaire Location

Characteristics

B.TRANSLUCENT MATERIAL

1. Diffuse surface Lamp shade To show imperfectionsor S-l Behind or within object for
irregularitiesin material backlighting (see Fig. 19-
15f)
2. Specular surface Glass enclosing globe To emphasize surface s-v Overhead to reflect image of
irregularities source to the eye (see Fig.
--``````-`-`,,`,,`,`,,`---

19-15m)
To check homogeneity s-IV Behind or within object for
backlighting(see Fig. 19-
15nì
~~ ~~

C.TRANCPARENT MATERIAL
Clear material with Bottles, glassware empty To emphasize surface irregu- S-l Directed obliquely at objects
specular surface or filled with clear liquid larities
To emphasize cracks, chips, S-IV or S-V Behind or within object for
or foreign particles backlighting (see Fig.
19-1511). Motion of light
source or object helpful

Successful inspection of very small objects is great- when, in fact, they are rotating at a dangerous speed.
ly improved by viewing them through lenses. For For some optional considerations, refer to the Section
production work, the magnified image may be pro- 3.7, Flicker and Strobe. The use of electronic ballasts
jected on a screen. Because the projected silhouette to operate fluorescent lamps at high frequency can vir-
is many times the actual size of the object, any irreg- tually eliminate flicker and strobe effects.
ular shapes or improper spacings can be detected
readily. Similar devices are employed for the inspec-
tion of machine parts where accurate dimensions 14.0 EMERGENCY, SAFETY AND SECURITY
and contours are essential. One typical device now LIGHTING
in common use projects an enlarged silhouette of
gear teeth on a profile chart. The meshing of these
production gears with a perfectly cut standard is Each of these subjects is covered at some length in
examined on the chart. Chapter 29 of the IESNA Lighting Handbook, 9th
Edition. Reference to that chapter is recommended
There are occasions when moving parts must be for further details on the design and selection of hard-
inspected or studied while they are operating. ware for these very important systems.
Stroboscopic illumination can be effective in this
process by adjusting the rate of “strobe” to stop or 14.1 Emergency Lighting
slow the apparent motion of constant-speed rotating
or reciprocating machinery. Stroboscopic lamps give Locating exit and unit emergency lighting equipment
flashes of light at controllable intervals (frequencies). can be improved when the designer visualizes how
The flashing can be so timed that when the flash occupants will need to move through the space in an
occurs, an object with rotating or reciprocatingmotion emergency. Buildings are usually large, complex and
is always in exactly the same position and appears to subject to materials being moved in and out continu-
remain stationary. This technique can be very effec- ously. In the event of an emergency where illumination
tive in allowing inspection of rotating parts without the is lost, it is likely that a worker could become confused.
necessity of stopping the process. Emergency lighting requirements are often covered in
codes or local ordinances that detail the levels of illu-
There is a potentially dangerous stroboscopic effect minance required, the duration of the lighting in the
unintentionally produced by fluorescent and HID event of a loss of power, and the types of power sup-
lamps and other sources operated on magnetic bal- plies that are acceptable to “the authority having juris-
lasts when flicker occurs on rotating equipment such diction.” Reference to these codes and ordinances is
as drilling, milling and lathe machines. At some rota- essential to ensure compliance with them.
tional speeds, these parts can appear to be stopped
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In addition, it may be helpful for lighting designers to used throughout the facility. Many industries use color
put themselves in the place of building occupants and as an indicator of danger and the selection of a lamp
mentally walk through the facility to ensure they have which does not accurately render all of the colors with-
provided lighting for exit and emergency egress and in the facility can compromise the identification of
all foreseeable conditions. these safety indicators by the occupants and lead to
dangerous conditions.
Often, in industrial areas, presses, conveyors and
other obstructions can defeat the emergency equip- It may be a code requirement that HID lighting sys-
ment, or obscure signage. A tour of the facility after tems have at least some of the luminaries fitted with
occupancy may be necessary to satisfy all parties that auxiliary incandescent lamps to provide light during
the emergency lighting is satisfactory. Final adjust- warm-up or re-strike times.
ments to the system are often necessary to accom-
modate unexpectedpieces of machinery or owner fur- 14.3 Security Lighting
nished obstructions installed during the project, which
can change the effectiveness of the originally In an industrial facility security lighting is usually
designed emergency lighting. required for protection of property, to discourage tres-
passers and to provide a means for guards to identify
14.2 Safety Lighting employees during shift changes. Security lighting
should be designed in consultation with the owner
Unlike emergency lighting, safety lighting is required and his personnel responsible for the safety of prop-
at all times when the building or outdoor space is erty and employees. Consulting with local law
occupied. This ensures the occupants’ ability to move enforcement departments can also aid in the design
safely throughout the facility without danger. In indus- of a security lighting system to ensure that the lighting
trial facilities there are many obstructions, potential will aid, and not hinder, those officers (and private
danger from moving equipment and manufactured security personne1)’in the performance of their duties.
goods, and hazards associated with the manufactur-
ing process. Minimum lighting for safety is recom- Security lighting methods for interior and exterior
mended in Figure 22. installations are discussed at length in Chapter 29 of
the IESNA Lighting Handbook, 9th Edition,and refer-
These values represent absolute minimum illumi- ence to that chapter is recommended.
nances at any time and location where safety is related
to visibility and they may require modification in some
instances to ensure proper visibility in particularly haz- 15.0 LIGHTING FOR SPECIFIC TASKS
ardous locations. Care must be taken in the design of
industrial lighting systems to guarantee the system will
provide not only the necessary illuminance for the tasks The lighting requirements for specific tasks can be
to be performed but will also adequately indicate dan- similar in a wide range of different industries. Whether
gers and hazards within the facility. In addition, the light- the task occurs in a steel plant, machine shop or elec-
ing should be free of glare, shadows and extreme illu- tronic assembly facility, the same lighting considera-
minance changes which could contribute to accidents. tions apply for that task. In past editions of this
Recommended Practice, consideration has been
Lamp selection is important in planning lighting for given to the lighting requirements in specific indus-
safety to ensure proper rendering of the safety colors tries. It is now felt the specific industry may be less
Figure 22. Illuminance levels for safety.
Hazards Requiring Degree of Hazard
Visual Detection Slight High
Normal Activity
Level Low High Low High

Illuminance Levels
Lux 5.4 11 22 54
Footcandles 0.5 1 2 5
These values represent absolute minimum illuminances at any time in locations where safety is related to visibility. (Note: the
illuminance conversion used here is 10.76 lux = 1 fc.) However, in some cases higher levels may be required (such as where
security is a factor). In other conditions, especially involving work with light-sensitive materials such as photographic film, much
lower illuminances may be used. In these cases, alternate methods of ensuring safety must be employed.
--``````-`-`,,`,,`,`,,`---

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 ANSI / IESNA RP-7-01

important than the requirements for lighting of a spe- or six grains of sand will cause imperfections in small
cific task. For those who are looking for specific indus- castings. The more exacting seeing tasks are repeti-
try lighting recommendations, refer to Annex A-2. tive and of interrupted and short-time duration.

15.1 Molding of Metal and Plastic Parts: Lighting should be designed for the intermittent, criti-
Discussion of Lighting and Equipment cal seeing of materials that have low reflectancesand
Choices unfavorable contrasts. The varying depths of mold
cavities demand adequate illumination without harsh
--``````-`-`,,`,,`,`,,`---

Metal castings and plastic parts are made in a variety shadows.

of sizes and shapes. Some are made to very close tol-
erances; others require less accuracy. The lighting Deep pit molds require additional consideration in
requirements for molding operations vary with the planning proper lighting.The walls of the pit may block
required accuracy and the severity of the seeing task. some of the light from the general lighting system and
A constant, however, is that foundry mold rooms and result in shadows and lower luminance, especially on
die-castingoperations tend to be dirty, requiring care- the vertical surfaces of the molds. Visibility in the pit
ful selection of luminaries, while injection molding is a areas will benefit from the installation of additional
relatively clean process. general lighting luminaries, located to avoid conflict
with materials handling equipment.
Maintenance in foundry and die-casting operations
may be minimizedby the use of ventilated or enclosed To improve visibility within the mold, placing white
and gasketed luminaries. Some luminaries have filters, parting sand around the opening sometimes increas-
which permit "breathing" but minimize the ingress of es contrast. When weights are used, the opening in
dust. Best practice dictates the use of the minimum the weight indicates the general location of the pour-
quantity of luminaries to provide the recommended ing basin.
illuminance and light distribution at the point of lowest
lamp output and highest dirt accumulation. 15.1.2 Molding Parts of Die-cast Aluminum and
Injection Molded Plastic
In areas where injection molding operations occur,
lighting can usually be provided by ventilated industri- The molding process involves forming parts from
al luminaries. Painting the ceilings and walls with a machined steel molds, or dies. The molds can be sin-
highly reflective paint finish will increase the benefits gle or multiple cavity, but have two halves, complete-
of an uplight component. ly encasing the part. The visual tasks are:

Melting, molding and coremaking usually involve 0 Inspecting the mold for foreign material
equipment with nonspecular surfaces. Where such 0 Applying the mold-releaseagent to the die
work is done in high-bay areas, high intensity dis- 0 Closing the die and actuating the mold cycle

charge luminaries may be installed without concern 0 Removing the part

for the introduction of reflected glare. 0 Performing secondary at-mold operations

0 Stacking or packaging of parts for material

15.1.1 Foundry Molding (Sand Casting) handling

The molding process involves forming molds from Lighting should be designed for the intermittent, criti-
treated sand. The visual tasks are: cal seeing of materials that have low and high
reflectances and unfavorable contrasts. The varying
Inspecting the pattern for foreign material depths of mold cavities demand adequate vertical illu-
Setting the pattern in the flask and packing sand mination that does not produce harsh shadows.
around it
0 Removing the pattern and inspecting the mold Proper general illumination contributes to safety. The
for loose sand and for accuracy of mold contour eyes of the workers often become adapted to the
Inserting core supports and cores (the operator bright, molten metal contrasted with dark surround-
must be able to see the core supports) ings. This adaptation may cause difficulty in seeing
Smoothing mold surfaces, checking core posi- any obstructions on a poorly illuminated dark-colored
tion and checking clearance between parts floor. Adequate lighting reveals such obstructions.

The size and detail of the tasks may vary. The small- 15.1.3 Inspection of Sand-castings
est task has a visual angle of about 1O minutes of arc
(1/6") corresponding to the size of separate grains of Quality control depends largely on visibility. A casting
sand A defect involving the misplacement of only five meets the specified tolerances when:
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Patterns are carefully checked against the Incoming Raw Materials. Raw materials are delivered
drawings to manufacturing facilities by truck or rail shipment.
Flasks are inspected for fit Both open-top and closed-top vehicles may be used.
Cores and molds are inspected for size, The visual task is to identify the materials and corre-
accuracy and alignment late the material and shipping documents. General
Core clearances are gauged prior to mold lighting with supplementary portable lighting for trailer
closing or rail car interiors is required.
Castings are checked against templates and
gauges Active Storage Areas. Raw materials are often
Surfaces are inspected and defective castings unloaded in the receiving areas by lift trucks or over-
are culled head cranes. They are transported to the active stor-
age areas or directly to the production process by the
Inspections are generally conducted at intermediate same means. The visual task is to identify the materi-
stages during the manufacture of the product. The als (labels or markings) from the cab of an overhead
inspections at some stages are either combined with crane or lift truck and to move the materials and
--``````-`-`,,`,,`,`,,`---

the functional operation or performed in the same deposit them at a designated location. Lighting
area. The type of inspection will dictate the proper requirements include general lighting with vertical illu-
quality and quantity of illumination. minance for identifying labels and markings and hori-
zontal illuminancefor reading pick tickets.
An inspection of the cores by the coremaker is per-
formed prior to baking. Later, the castings may be Parts Manufacturing Processes. Several different
inspected and, if necessary, scrapped by the types and sizes of parts using many unique processes
shake-out handlers or by the grinder operators, avoid- may be manufactured in a single plant. The designer
ing subsequent waste of labor on defective parts. should refer to other sections of this document for
Proper lighting will allow this inspection to be done major activities that occur in manufacturingplants such
quickly and effectively at this stage of production. as machining, sheet metal fabrication, and casting. A
Small castings are frequently inspected and sorted number of different tasks may be performed. These
simultaneously. are described under their own subheadings. General
lighting is required with properly positioned supple-
15.1.4 inspection of Die-castings and Opaque mentary lighting in areas or on equipment.
Injection Molded Plastic Parts
Parts Assembly. In many manufacturing plants, indi-
Most parts of this type have specular or semi-specu- vidual components are assembled into subassem-
lar surfaces, against which flaws are seen under cat- blies. The assembly process combines manual, semi-
egory s-1V supplementary lighting (see Figure 18.) automatic and automatic activities. The visual tasks
Parts that have a matte (or heavier) texture in the are to select, orient, install and fasten a component to
mold are inspected much like sand castings, and the subassembly. General lighting with supplemen-
have similar lighting requirements. tary lighting added to specific work station positions
will help to reduce shadows.
In sorting areas, a simple, general lighting system of
ventilated fluorescent industrial luminaries may be Testing. Highly diversified and complicated proce-
mounted 1.2 m (4 ft) or more above the sorting table dures and test equipment determine compliance with
or conveyor. Atmospheric and maintenance condi- design specifications for many subassemblies.
tions will determine the type of luminaries (open, Testing activities are manual, semiautomatic and
enclosed or filtered) to be used. automatic. The visual tasks are to secure the assem-
bly to the testing device; to perform tests on electrical
For medium inspections, fluorescent luminaries may or mechanical connections; to run tests and read
reduce reflected glare and improve diffusion of light. gauges and meters; to perform mechanical or electri-
Medium-fine and fine inspection sometimes require cal adjustments as required; to complete test reports;
special lighting equipment. to disconnect and remove the assembly from the test-
ing device. General lighting and properly positioned
15.2 Parts Manufacturingand Assembly supplementary lighting are required.

Common tasks in manufacturing facilities include the Final Inspection. Inspection determines whether the
manufacture of parts and the joining of those parts into manufactured part or subassembly is in total compli-
larger sub-assemblies. Some of the important seeing ance with the design specification. The visual tasks
tasks and typical lighting systems are as follows: are inspecting the part or subassembly for specifica-
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 ANSI / IESNA RP-7-01

tion compliance and to verify that all intermediate

16.0 LIGHTING FOR SPECIFIC VISUAL TASKS
inspectionsand tests are satisfactory. General lighting
with supplementary lighting to inspect the part or sub-
assembly is required. Note that good color rendering
This section describes certain industrialvisual tasks and
light sources should be used.
suggested lightingtechniques for addressing them.
Packing. Parts are manually or semiautomatically
16.1 Convex Surfaces
placed in boxes, containers or racks for shipment. The
visual tasks are to identify the part and place it in a
Discriminating detail on a convex surface, as in read-
destination-designated shipping container or rack.
ing a convex scale on a micrometer caliper, is a typical
General area lighting is required. (See Figure 23,
seeing task. The reflected image of a large-area
color insert.)
low-luminance source on the scale provides excellent
contrast between the dark figures and divisions and
Shipping. Parts may be shipped to other plants or
the bright background without producing reflected
warehouses in enclosed rail cars and trucks. Lift
glare. The use of a near-pointsource for such applica-
trucks are generally used to load these vehicles. The
tions results in a narrow, brilliant band that obscures
visual tasks are to identify a shipping container or rack
the remainder of the scale because of the harsh spec-
by part and destination and load it into the designated
ular reflection and loss of contrast between the figures
rail car or truck. (See Figure 24, color insert.)
or divisions and the background. (See Figure 25.)
--``````-`-`,,`,,`,`,,`---

General lighting with adjustable or portable supple-

mentary lighting will provide good vertical illuminance
for the rail car or truck trailer interior.

15.3 Machining Metal Parts

While computer numerically controlled (CNC)

machines do most precision work, much of the follow-
ing information still applies, especially as pertainingto
Set-up work. Machining of metal parts consists of the
preparation and operation of machines such as lath-
es, grinders (internal, external and surface), millers
(universal and vertical), shapers and drill presses,
bench work, and inspection of metal surfaces. The
precision of such machine operations usually
depends upon the accuracy of the setup and the care-
ful use of the graduated feed-indicating dials rather
than the observation of the cutting tool or its path. The
work is usually checked by portable measuring instru- Figure 25. (Left) Micrometer illuminated with a sys-
ments, and only in rare cases is a precision cut made tem of small, bright sources is seen with bright
streak reflections against a dark background. (Right)
to a scribed line. The fundamental visual task is to dis- When illuminated with a large-area, low-luminance
criminate detail on planar or curved metallic surfaces. source, the micrometer graduations are seen in
excellent contrast against a luminous task back-
General Lighting: Most of the visual tasks in the ground.
machining of metal parts are best lighted by large-
area low-luminance sources. The ideal general light- 16.2 Flat Surfaces
ing system would have a large indirect component.
While both fluorescent and high-intensity discharge In viewing a flat surface, such as a flat scale, the see-
sources can be used for general lighting, fluorescent ing task is similar to that in reading a convex scale.
luminaries, particularly in a grid pattern, are some- With a flat scale, however, it is possible, depending on
times preferred for low mounting heights. the size, location and shape of the source, to reflect
High-reflectance room surfaces improve illumination the image of the source either on the entire scale, or
and visual performance. only on a small part of it. If the reflected image of the
source is restrictedto too small a part of the scale, the
Since workers often refer to information on CRT reflection is likely to be glaring.
screens, the needs of this visual task must be consid-
ered. In particular this refers to veiling reflections on 16.3 Scribed Marks
the CRT screen from luminaries, light surfaced walls,
and windows. The visibility of scribed marks depends upon the char-
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acteristics of the surface, the orienta- Size source

required
tion of the scribed mark and the
nature of the light source. Directional
light produces good visibility of
scribed marks on untreated
cold-rolled steel if the marks are ori- Eve
n
ented for maximum visibility, so that
the brightness of the source is reflect-
ed from the side of the scribed mark
to the observer’s eye. Unfortunately,
this technique reduces the visibility of
other scribed marks. Better results
are obtained with a large-area
low-luminance source. If the surface Width of \
luminous area \
\.
\\
to be scribed is treated with a \ \
\
low-reflectance dye, the process of
scribing will remove the dye and “\
expose the surface of the metal. Figure 26. Procedure used for establishing the luminaire size necessary
Such scribing appears bright against to obtain source reflections on a flat specular surface.
a dark background. The same tech-
nique is appropriate for lighting specular or diffuse alu- 16.7 Convex Specular Surfaces
minum. In this case, the scribed marks will appear dark
against a bright background. The appropriate width of the luminous area of the con-
vex surface is shown in Figure 27. Draw lines from
16.4 Center-Punch Marks the location of the observer’s eye to the edges of the
surface’s luminous area, forming angle a. Erect nor-
A visual task quite similar to scribing is that of seeing mals at intersectionsof lines with the surface. At these

--``````-`-`,,`,,`,`,,`---
center-punch marks. Maximum visibility is obtained intersections and on the other side of the normals,
when the side of the punch opposite the observer construct lines to form angles equal to those to the
reflects the brightness of a light source. A directional eye (the same procedure as that for flat surfaces
source located between the observer and the task described above). Project lines (as for flat surfaces) to
provides excellent results when the light is at an angle define the luminaire width. This procedure can be
of about 45”with the horizontal. applied to concave surfaces.
Size source
16.5 Concave Specular Surfaces

The inspection of concave specular surfaces is diffi-

required
I I
I
cult because of reflections from surrounding light /
I
sources. Large-area, low-luminance sources provide I
/ E??
the best visibility. In the machining of small metal position
parts, a low-luminance source of approximately 1700
cd/m* is desirable. The size of the source depends on Established
mounting
’\ \
the shape of the machined surface and the area from height \
which it is desired to reflect the brightness. The tech- I .‘(
niques applicable to specular reflections can also be
applied to semispecular surfaces.

16.6 Flat Specular Surfaces

The geometry for determining luminous source size is

illustrated in Figure 26. First, draw lines from the
extremities of the surface that is to reflect the source, to
the location of the observer’s eye, forming an angle a. At /..- Width of
luminous area
the intersections of these lines with the plane of the sur- 8=2u+a
face, erect vertical lines from that plane, forming angles
Figure 27. Procedure used for establishing the lumi-
b l and b2. Project these lines to the luminaire location naire size necessary to obtain source reflections on a
to define the luminaire width; extend them in the oppo- convex specular surface. In the diagram, q = 2s + a.
site direction until they intersect, forming an angle.
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16.8 Lighting and Visibility Issues for Specific 16.8.2 Shear

Visual Tasks for Sheet Metal Fabrication
The operator must be able to see a measuring scale
Visual tasks in the sheet metal shop are often difficult in order to set the stops for gauging the size of cut.
because sheet metal (after pickling and oiling) has a When a sheet has to be trimmed, either to square the
reflectance similar to the working surface of the sides or to cut off scrap from the edges, the operator
machine, resulting in poor contrasts between the must be able to see the location of the cut in order to
machine and work. Low reflectance of the metal results minimize scrap;
in a low task luminance. High-speed operation of small
presses reduces the available time for seeing and bulky The general lighting system should provide adequate
machinery obstructs the distribution of light from gener- illuminance in the area around the shear to safely feed
al-lighting luminaries. Noise also contributes to fatigue. the sheets at the front, collecting the scrap at the back
and stacking the finished pieces in preparation for
16.8.1 Punch Press removal. Local lighting should indicate where the cut
will be made and the amount of scrap that will be
The seeing task is essentially the same for a large trimmed. It also provides light to enable the operator,
press as it is for a small press, except that with a small who is responsible for pressing the foot-release bar, to
press less time is available for seeing. The shadow see quickly that all hands are clear of the guard.
problem, however, is much greater with a large press.
The operator must have adequate illuminance, often 16.9 Lightingfor Large Component Sub- and Final
from supplementary or task lighting, to move the stock Assembly
into the press, inspect the die for scrap after the oper-
ating cycle is completed and inspect the product. This phase of manufacturing has special require-
Where an automatic feed is employed, the speed of ments not usually found in other industrial operations.
operation is so great that the operator has time only to Modern industrial requirements have necessitatedthe
inspect the die for scrap clearance. construction of buildings with clear bay areas, which
may exceed 26,000 m2(300,000 ft2)and truss heights
The general lighting system in press areas should of more than 24 m (80 ft) from floor level. The lighting
provide illuminance adequate for the safe and rapid problems in buildings of this size are not confined to
handling of stock in the form of unprocessed metal, the engineering and design concepts but include the
scrap or finished products. In large press areas illumi- task of maintenance and lamp replacement. The use
nation should be furnished by high-bay lighting equip- of either a system of catwalks or traveling-bridge
ment or by a combination of high-bay and supple- cranes may be appropriate to allow access to the
mentary task lighting. For moderate mounting heights, lighting units. In some cases, mobile telescoping
the illuminance should be supplied by luminaries hav- cranes can be used to reach luminaries from the floor,
ing a widespread distribution to provide uniform illumi- but the heights involved and obstructions on the floor
nance for the bay and the die surface area. may make this method of maintenance impractical.
Where access is available from the floor, disconnect-
The operator’s ability to inspect the die is more direct- ing hangers and lowering chains can be an effective
ly related to the reflected brightness of the die Surface method for maintaining luminaries in high-bay areas.
than to the amount of light incident upon it. For exam-
ple, a concentrated light placed on the operator’s side One special problem in lighting certain assembly
of the press and directed toward the die may produce tasks, is that the lighting is usually designed to specif-
results much less satisfactory than a large-area ic task levels with the assumption that the areas will
source of low luminance placed at the back or side of be completely open, whereas in reality that is seldom
the press. The luminance required for optimum visibil- so. The lighting from overhead systems is often
ity of the die has not been established; consensus reduced by the presence of large assemblies or large
suggests that 1700 cam2 is satisfactory. production equipment. .
Paint applied to both the exterior and the throat surfaces Typical of the types of assemblies found in these facil-
of a press contributesto the operator’s ability to see. The ities are aircraft and automobile sub-assemblies and
reflectance of the paint selected for the exterior of the the installation of sub-systems in these assemblies for
press should be not less than 40 percent. This treatment which supplementary lighting is often required.
of vertical surfaces on the exterior provides for maxi-
mum utilization of light from the general lighting system. Assembly of large aircraft sections, for instance, can
Similarly, the paint selected for throat surfaces should present special lighting problems. Exterior lighting for
have a reflectance of 60 percent or higher. joining together these sections requires both horizon-
--``````-`-`,,`,,`,`,,`---
tal and vertical illuminance as well as lighting installed

42
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in such a manner that it will light the underside of the

body and wings. Use of floodlights can give both com-
ponents of light on the exterior body and also provide
--``````-`-`,,`,,`,`,,`---

light to the undersides of the body and wings.

Specially mounted luminaries or portable lighting are
required to light areas such as landing-gear pockets.
High reflectance floor finishes will aid in lighting the
underside of assemblies but supplementarylighting is
still usually required. See Figure 28 (a) , (b) and (c).

Figure 28 (b) for aircraft assembly. (Photo courtesy

of Holophane.)

Figure 28 (a) Light surfaces, including the floor,

insure high quality lighting (a) for truck assembly.
(Photo courtesy of Hubbell Lighting.)

16.10 Control Rooms

The control room is the nerve center of facilities such as

electric generating plants, electric-dispatch facilities,
steam or hot water generating plants, and chemical
plants, and it must be continuously monitored. Lighting
must be designed with special attention on the comfort
of the operator; direct and reflected glare and veiling
reflections must be minimized, and luminance ratios
must be low. Along with ordinary office-type seeing
tasks, the operator has to read gauges, meters and
other monitoring devices, often at distances of 3-4.5 m
(10-15 ft) away. Reflected glare and veiling reflections _I
--
--I_---- ~ -
must be eliminated from these indicating devices, Figure 28 (c) for maintenance in a hangar. (Photo
including those with curved glass faces. courtesy of Ruud Lighting.)

While the practice is not standardized, most As control room data displays are more and more dig-
control-room lighting involves one of two general cat- ital, the problems concerning lighting and CRTs are
egories: diffuse lighting or directional lighting. Diffuse more in evidence. Many operators like to have black
lighting may be from low-luminance, indirect lighting or dark colored backgroundson their CRTs in order to
equipment, solid luminous plastic ceilings or louvered increase the contrast between pixel derived data’and
ceilings. Directional lighting may be from recessed its background. In this instance the veiling reflection
troffers, which follow the general contour of the control problems are increased over those with light back-
board. (These luminaries must be accurately located ground panel meters. Under these conditions light
to keep reflected light out of the glare zone.) Lighting surfaced walls behind the operator, walls and lighting
for the rest of the room may be from any type of outside of glass partitions, floors and even light
low-luminance general lighting equipment. reflecting off the operator’s clothing and the table sur-

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faces next to the operator can show up as a veiling Stockroom Area: Identification marks on the sides of
reflection in the CRT screen. bulky materials, rolls of paper, and crates or boxes
require vertical illumination. Additional lighting should
Often, the orientation and tilt angle of these CRT be provided over the aisles where high piles of stock
screens may not be easily adjusted to reduce objec- interfere with general lighting.
tionable screen reflections. In these cases, control of
sources of direct and reflected light relative to the Cold Storage. Areas that warehouse normally per-
screens and operators is even more critical. (Figure ishable food items and require low (sometimes below
29, see color insert.) freezing) temperatures. See Section 10.5 on Low
Ambient Temperatures.
16.11 Warehouse and Storage Area Lighting
Hazardous Materials Storage. Areas where haz-
Placing items in storage, accounting for them and ardous gases, vapors, or dust are or could be present
later retrievingthem are some of the most widespread require specific methods of storage. Local building
activities requiring electric lighting in industrial facili- code requirements should be checked as to permissi-
ties. Storage activities are found in business opera- ble luminaries for lighting areas where hazardous
tions of every type, ranging from small local opera- materials are stored or used. See Section 10.5 on
tions to multinational corporations. Classified Areas.

Since rapid changes are taking place, the traditional Exit and Emergency. Areas within warehouses that
concept of the warehouse must be expanded to provide safe passage through to exit from the building
encompass new techniques, including automation, and that must conform to Life Safety Codes in case of
high-rise storage, bar coding, cold storage, and emergency.
shrink-wrap packaging.
Shipping and Receiving.Areas where materials are
16.11.1 Types of Warehouse Area and Storage received into the warehouse for sorting and piace-
Systems ment in storage areas. Areas that setve as staging
areas for coordination of products to be sorted and
A variety of warehouse areas and storage systems placed on trucks or trains to be shipped. One of the
requiring specific tasks may occur in warehouse most difficult visual tasks is reading markings on ship-
usage: ments, labels and bills of lading. General illumination
may provide sufficient light for these tasks and for the
Open Storage. Areas of material stored without the operation of manual or powered forklift trucks, as well
use of rack systems. This includes storage on the floor as for general traffic in the area.
and on pallets, which may be stacked on each other.
--``````-`-`,,`,,`,`,,`---

In Figure 30 (see insert page IV) the center area of a Supplementary lighting may be necessary for the interi-
production facility is used for storing aluminum coils. or of transport carriers bringing material to the plant.
Angle or projector-type luminaries may be utilized, but
High Rise. Areas generally automated, where storage care must be taken to avoid glare from these sources. If
bins may be rotated so that unused bins are kept high the conveyances are deep, reel-type or other portable
up, and with storage levels rising to over 30.5 m (1O0 ft). lighting equipment may be necessary. Yard or load-
ing-dock lighting should be installed for night operation.
Fixed Racking. Areas with fixed racking may range
from 1-4 m (3-12 ft) wide and from 2.5-9 m (8 to 30 ft) Loading Docks and Staging Areas. Areas, generally
high. Items may be in bins, on racks, or in various just outside the shipping area, that may be outdoors but
types of containers. Labeling of the racks, containers are often covered and that are used to place items on
or bins can vary from large black-on-white lettering to and off trucks and railroad cars and to assemble goods.
small, hard-to-read hand written labels.
Maintenance Shops, Fork Lift Recharging Areas
Mobile Racking. A storage system now widely used and Refrigeration Equipment Rooms. Locations
in North America. Entire blocks of racking move on where general plant housekeeping activities occur.
floor-mounted rails to open and close aisles as need- Separate areas or rooms are generally set aside for
ed. In order to obtain maximum use from any lighting these purposes.
provided, the definition of the actual seeing task
should be considered. 16.11.2 Warehouse Illuminance3

Offices. Papetwork areas located within warehouses Vertical illuminance. From the tasks encountered in
require lighting appropriate for office tasks. the warehouse, it can be concluded that the majority

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of critical seeing tasks occur in a vertical plane. A Recommended illuminancelevels for warehouses are
major consideration, therefore, in warehouse lighting shown in Figure l(a).
design is providing illuminance on the vertical sur-
faces of stored goods. Illuminance should be distrib- 16.11.3 Warehouse Lighting Design Considerations
uted uniformly over the entire vertical seeing surface,
from top to bottom, and along the entire length of stor- Since storage in fixed-location racking generally
age aisles. (See Figure 31 .) results in long narrow aisles, lighting layout and cal-
culation procedures should be based on the dimen-
sions of the aisle space rather then the overall build-
ing size parameters. Lighting fixtures should be locat-
ed over the aisles (generally in the middle), regardless
of the overall building configuration. Because of the
special geometry of aisle space, which generally
yields cavity ratios higher than 10.0, and because the
determination of vertical illuminance is a key task, the
Lumen Method of average illuminance calculation
(see Annex C) is not effective for such warehouse
calculations. Computer programs for point-by-point
calculation of both horizontal and vertical illuminance,
now generally available throughout the industry, are
much more effective calculation tools.

To help ensure a productive work environment, glare

--``````-`-`,,`,,`,`,,`---

from light sources should be minimized. This

becomes particularly important when concentrated
HID sources are used because operators working
beneath luminaries may encounter disability glare
when looking up to the top of stacks. Proper shielding
of the source needs to be considered, as well as view-
ing angles up and along the aisles.

Indirect lighting systems for warehouses, while not as

Figure 31. Warehouse with uniform distribution efficient in producing illuminance, can be useful in pro-
along the length of the storage aisle. (Photo cour- viding excellent seeing results and have proved partic-
tesy of Holophane.)
ularly useful in areas with computer terminals and
where both storage and selling take place. Ceiling sur-
The reflectances of exposed surfaces can significantly
faces with high reflectance characteristics are impor-
affect lighting results. While the reflecting characteristics
tant when considering indirect lighting systems.
of stored goods cannot be controlled at the warehouse
operating level, they should be taken into consideration
Aisles or narrow “rooms” can be lighted with HID
when carton and container decisions are being made.
sources in classical high-bay luminaries, provided that
Light-colored packing material can contribute to efficient
the luminaries are spaced reasonably close together to
utilization of available light and increase visibility through
avoid unacceptable drop-off of illuminance between
greater contrast. Clear plastic wrappings over packages
luminaries. The spacing can be increased with luminar-
can reduce visibility of labels and markings due to
ies that have a substantial uplight component when the
reflected glare from the plastic wrap.
ceilings have high reflectance. Other equipment choic-
es include low-bay luminaries or special aisle luminar-
Some racks and storage locations may be partly or
ies that have an asymmetric light distribution. HID
wholly empty at times. The lack of reflecting surfaces
sources in appropriate luminaries are generally most
in the empty shelves may reduce the overall illumi-
effective at mounting heights of 5 m (15 ft) or more.
nance. This effect should be anticipated and included
Special care must be taken at higher mounting heights
in the design parameters.
to ensure that sufficient illuminance is produced along
the entire height and length of the aisle stacks, espe-
Horizontal illuminance. While not as critical as the
cially when wider luminaire spacings are used.
need for vertical illuminance, adequate horizontal illu-
minance must be providedfor safety and navigation in
Fluorescent lighting is frequently used for warehouse
the aisles. Other horizontal-planetasks include read-
aisles and can be used effectively in mounting heights
ing of documents such as pick tickets.
up to about 1O meters (30 ft). Fluorescentdesigns are
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 ANSI / IESNA RP-7-01

implemented either with continuous rows along an When coverage is more than two mounting heights
aisle (in reflector, lensed, open strip types) or with transversely, narrower distributions, such as NEMA 2
individually mounted units. and NEMA 3 are called for.

Warehouse spaces are often accessed only intermit- Coverage greater than four mounting heights from a
--``````-`-`,,`,,`,`,,`---

tently. It is therefore possible to save energy by con- location is not recommended. The use of projected
trolling light output with passive infra-red sensors or lighting has a greater potential for direct glare and
other control devices. Lamps are switched off or oper- obtrusive light than distributed lighting.
ated at reduced output at inactive times and then
operated at full output only when the space is in use, Projected outdoor area lighting has the fewest loca-
or, in the case of a passive infra-red sensing system, tions and thus requires the least amount of aria1struc-
when a person is present. Multilevel fluorescent and ture. Structures are usually the most expensive part of
HID ballasts have been developed for this purpose. the lighting system.
These lamps are operated at reduced levels when
there is no activity, and a sensor activates the circuit 17.2 Distributed Lighting System
when someone is present in the space. Significant
energy savings can be realized, depending on the Distributed lighting differs from projected lighting in
occupancy patterns of the space. that luminaries are installed at many locations.

Advantages are:
17.0 OUTDOOR AREA LIGHTING
1. Good illuminance uniformity on the horizontal
plane
Two different systems of lighting are commonly used 2. Glare can be controlled with the proper selection
to illuminate large, outdoor areas of industrial facilities: of cut-off luminaries
projected (long-throw) lighting and distributedlighting. 3. Good utilization of light (less wasted spill light)
Each has its advantages under specific situations. 4. Reduction of undesirable shadows
5. Less critical aiming
17.1 Projected Lighting System 6. Lower mounting heights (floodlight maintenance is
facilitated)
The function of this system is to provide illumination 7. Reduced losses to atmospheric absorption and
from a minimum of locations throughout the various scattering
outdoor work areas. This is usually accomplished by 8. The electrical distribution system serves a large
use of aimable floodlighting luminaries. (Figure 32, number of small, distributed loads
see color insert.)
In the Distributed Lighting method, wall mounted
Advantages are: equipment is often used at personnel and loading
dock doors. Wall mounted equipment, however,
1. The use of high poles on towers reduces the should rarely be used to cover a transverse dimen-
number of mounting sites. sion greater than two mounting heights and a longitu-
2. The light distribution is flexible. Both general and dinal (horizontal, to the side) area more than 4 mount-
local lighting are readily achieved. (Aiming of ing heights. This would place continuous area lighting
floodlights, however, may be more critical.) equipment on 4 mounting height spacing along a wall.
3. Floodlights are effective over long ranges.
4. Lighting system maintenance is restricted to a few Distributed outdoor area lighting systems have the
concentrated areas. least amount of glare because mounting heights can
5. Physical and visual obstructions are minimized. be lower. When floodlights are used, aiming angles
6. The electrical distribution system serves a small can be less oblique, thus permitting glare control
number of concentrated loads. media such as louvers and visors to work. Care
should be taken to keep aiming angles below 65
Typically wide beam floodlights such as NEMA 5 degrees above nadir.
through NEMA 7 distributions are not used to cover
areas wider than two mounting heights in front (trans- 17.3 Outdoor Tower Platforms, Stairways, and
verse dimension) of their locations. Individual floodlights Ladders
should not cover more than 90 degrees in the horizon-
tal plane. This means that at least two luminaries are Luminaries should provide uniform illumination and
needed when the location is at the side of an area. Four be shielded from direct view of persons using these
are needed for locations in the center of an area. structures. Enclosed and gasketed or weatherproof
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luminaries equipped with refractors or clear, gasket- contribute to the visual response. This vision is gen-
ed lenses may be used for reading gauges. erally associated with adaptation to a luminance
--``````-`-`,,`,,`,`,,`---

Luminaries above top platforms or ladder tops should between 3 and 0.001 cd/m2 (0.3 and 0.0001 cd/ft2).
be equipped with refractors or reflectors. Reflectors Low illuminance design should take into account the
may be omitted on intermediate platforms around prevalence of mesopic conditions.
towers so that the sides of the towers will receive
some illumination and the reflected light will mitigate When clarity, depth of field, and peripheral detection
deep shadows. If luminaries are attached to equip- are important, then a light source rich in short wave-
ment, care should be taken in mounting the luminar- length (blue and green) light should be used. Current
ies to reduce damage from equipment vibration. research4indicates that less light is required with a
light source rich in green and blue components (metal
Normal installations have intense HID sources locat- halide, fluorescent) relative to a light source with few
ed fairly close to personnel. Exchanging coated for blue green and blue components, for an equivalent
clear lamps may reduce glare in these situations, but mesopic response.
may also significantly change the light distribution
from luminaries. Sources of different spectral composition that affect
the eye equally at 3 cd/m2(0.03 cd/ft2)and above may
17.4 Special Equipment not affect the eye equally when those same sources
are used at lower adaptation levels. This includes
Special lighting equipment may be needed for such color matching, off-axis reaction time, and brightness
functions as illuminating the insides of filters or other perception. The spectral sensitivity of the eye and the
equipment whose operation must be inspected effects of the spectral composition of light sources on
through observation ports. If the equipment does not brightness perception should not be confused with
include built-in luminaries, concentrating-type reflec- color rendering tasks or with color naming.5t6
tor luminaries should be mounted at ports in the
equipment housing. References
Rea, M., Editor, IESNA Lighting Handbook, 9th
Portable luminaries are utilized where access holes Edition, 2000. New York: Illuminating Engineering
are provided for inside cleaning and maintenance of Society of North America.
tanks and towers. Explosion-prooftypes (where haz-
ardous conditions may exist) with portable cables are IESNA. Lighting Economics Committee. 1996.
connected to industrial receptacles (either Recommended Practice for the Economic Analysis of
explosion-proofor standard as may be appropriatefor Lighting, IESNNRP-31-96. New York: Illuminating
the atmospheric conditions present) located near Engineering Society of North America.
tower access holes or at other locations.
IESNA. Industrial Lighting Committee. 1992. Design
17.5 Low Illuminanceand Visual Acuity Outdoors Guide on Warehouse Lighting. IESNNDG-2-92. New
York: Illuminating Engineering Society of North
In outdoor environments with low illuminance levels, America.
the human eye’s processes of visual adaptation oper-
ate in three categories of vision: Photopic, Scotopic McGowan, T. and Rea. M. S., 1995. Visibility and
and Mesopic. spectral composition:Another look in the mesopic. 70
Years of CIE Photometv. Vienna: Commission
Photopic Vision is the human eye’s response at high Internationale de 1”Eclairage.
light levels where the cones in the eye account for the
majority of vision. This vision is generally associated “Vision at Low Light Levels” Symposium, May 1998,
with adaptation to a luminance of 2 3 cdm‘ (20.3 c w ) . Electric Power Research Institute, Lighting Research
Office.
Scotopic Vision is the human eye’s response at very
low light levels such as moonlight where the rods in Rea, M. S., Essay by Invitation, Lighting Design and
the eye account for the majority of vision. This vision Application, Vol. 26 No.10 p.15. New York:
is generally associated with adaptation to a luminance Illuminating Engineering Society of North America,
of f 0.001 cd/m2 (f 0.0001 cd/ít2). Scotopic vision is October, 1996.
largely irrelevant to most lighting design practice.

Mesopic Vision occurs under the majority of exterior

night lighting conditions and is a combination of pho-
topic and scotopic vision. Both the rods and cones
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 ANSI / IESNA RP-7-01

(This Annex is not part of the American National ations or more) would be 'x more or 'x less than the
Standard and Practice ANSIAESNA RP-7-2001.) recommended value. Such dramatic deviations should
be carefully documented by the designer as part of
~ ~~ ~~
good professional practice and for future reference.
ANNEX Al
THE BASIS FOR DEVIATING FROM
RECOMMENDED ILLUMINANCES
The recommendations ' for illuminance in this
Recommended Practice are not made with respect to
Occasionally the visual task in a specific space is not the age of the occupants. Generally the visual require-
typical and Figures A l .1 and A l .2 should be used to ments of older persons are significantly different from
adjust the illuminance for that task. It is extremely those of younger persons in two ways:
important that the lighting designer have a clear
understandingof the visual task being illuminated and There is a thickening of the yellow crystalline lens, which
then determine if the recommended illuminance is decreases the amount of light reaching the retina,
appropriate. It is also possible that more than one increases scatter within the eye, and reduces the range
visual task is performed in a space. The designer of distances that can be properly focused (presbyopia)
should make provision to illuminate these tasks to the
recommended levels unless other design criteria There is a reduction in pupil size, decreasing the
supercede illuminance as the design criterion. amount of light reaching the retina.

A dramatic difference between an actual and a recom- The retinal illuminanceof a 60-year-oldperson is only
mended illuminance(a difference of two standard devi- about one-third of the retinal illuminance of a typical

Figure A l .1 Determination of visual task parameters.

~~ ~~~~

CONTRAST
How to calculate:
IL, - Li/Lb or Ipb- ptl/p,
where L is luminance (L,, and L, must use same units)
and p is reflectance
b refers to the background
t refers to the target
Definition of contrast using reflectance requires equal
illuminance on task and background.

How to interpret:
low contrast: 0.3 or lower, but not near threshold*
high contrast: above 0.3
This division is based on the plateau-escarpmentnature of visual performance 1.2

SIZE (see also Figure Al -2)

How to calculate:
Target
solid angle (sr): (d' cos8)/l?

where d, 8 and I are defined as for visual angle

visual angle: arctan(d cosû)/l
where d is the dimension (length or width) of the critical detail of the target
8 is the viewing angle
I is the viewing distance (d and I are in the same units)

Note that only one dimension, d, is defined for the critical detail of the target. Visual performancefor two different
targets subtending the same area will be the same, even if the targets have different aspect ratios, e.g., a square-
shaped target versus a long, rectangular-shapedobject1,

--``````-`-`,,`,,`,`,,`---

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How to interpret:
small size: 4.0 x lo6 sr or smaller (solid angle), but not near the acuity limit*
large size: larger than 4.0 x sr

Note: 1" = 0.0175 radians = 60 minarc; 1 sr = 66" visual angle for a circular target. For a cone where 9 is the
half-cone angle, solid angle = 2n(1 - cosq).

This division, like that of contrast, is based upon the plateau-escarpmentof visual performance.l.*

*It should be noted that contrast threshold and the acuity limit are dependent upon background luminance, duration
of presentation, color, surround conditions, and in general, any number of factors that affect visibility, including those
idiosyncratic to the viewer. Above a contrast of 0.3 and a size of 4.0 x 1O* sr, these factors are not very ¡important to

--``````-`-`,,`,,`,`,,`---
visual performance.

Figure A1-2. Examples of common visual angles and solid angles.

Printed reading task from 15 in. (40 cm)

Typeface size Visual angle (")* Solid angle (sr)f
6 point 0.03 1.7 x lo6
8 point 0.04 3.1 x lo6
10 point 0.05 4.8 x l o 6
12 point 0.06 6.9 x
14 point 0.07 9.4 x 10-6
24 point 0.12 2.8 x 10-5
36 point 0.18 6.2 x 10-5

*Angular width of single character stroke (vertical stroke, Times typeface).

+Averagesolid angle of total printed area of character for numerical digits (see reference 1).

Viewing a square-shaped object from 100 ft (30 m)

Object size Visual angle (") Solid angle (sr)
3 x 3 in. (7.5 x 7.5 cm) 0.14 6.3 x lo6
6 x 6 in. (15 x 15 cm) 0.29 2.5 x 10-5
12 x 12 in. (30 x 30 cm) 0.57 1.0 x 10"

Wire sizes (diameter in cross section) viewed from 15 in. (40 cm)
Wire size Visual angle (") Solid angle (sr)
American Wire Gauge (AWG) 30
(0.25 mm diameter) 0.04 3.9 x 1 0 7
AWG 24 (0.51 mm diameter) 0.07 1.6 x lo6
AWG 20 (0.81 mm diameter) 0.12 4.1 x lo6
AWG 16 (1.29 mm diameter) 0.18 1.0 x 105
AWG 12 (2.05 mm diameter) 0.29 3.3 x 10-5
AWG 8 (3.28 mm diameter) 0.47 6.7 x 10-5

Circular drilled holes viewed from 15 in. (40 cm)

Hole diameter Visual angle (") Solid angle (sr)
0.01 in. (0.25 mm) 0.04 3.5 x 107
0.02 in. (0.51 mm) 0.07 1.4 x lo6
0.03 in. (0.76 mm) 0.11 3.1 x lo6
0.04 in. (1 .O2mm) 0.15 5.6 x lo6

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 ANSI / IESNA RP-7-01

20-year-old person due to smaller pupil sizes and Consequently, older persons tend to require higher
thicker lenses. (See Figure A l .3.) Additionally the task illuminances for the same retinal illuminance and
near point of a typical 20-year-old person is 10 cm (4 because of reduced clarity in the lens, have reduced
in.), compared to more than 1 m (3ft) for a typical 60- image quality. Similarly, greater attention to sources of
year-old person. (See Figure A l .4.) glare within the field of view is more important for
older than for younger persons for reasons of
increased light scatter within the aged eye.

References

Rea, M.S. and Ouellette, M.J. 1991.“Relative visual

performance: A basis for application.” Lighting
Research and,Techno/ogy.23(3):135-144.

Rea, M.S. and Ouellette, M.J. 1988.“Visual perfor-

mance using reaction times.” Lighting Research and
Techno/ogy.20(4):139-53.

Age in years

Figure A l .3An estimate of‘ relative decline in retinal

illuminance with age.
--``````-`-`,,`,,`,`,,`---

16

14

12

10

O
10 20 30 40 50 60 70
Age in years

Figure A l .4 l h e decrease of amplitude of accommo-

dation with age.
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(This Annex is not pari of the American National Standard and Practice ANSVIESNA ßP-7-2001.)

ANNEX A2
RECOMMENDED ILLUMINANCE VALUES (TARGET MAINTAINED) FOR INDUSTRIAL LIGHTING DESIGN

Figure A2-1 Recommended Illuminance Values for Industrial Areas/Activitiec - Interior

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ater treatinu areA

Explosives manufacturing
Hand h a c e s , boiling tanks, stationary driers, stationary and gravity crystallizers 300 (30)
Mechanical furnace, generators and stills, mechanisai dners, evaporators, filtration, 300 (30)
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Fabric dyeing (printing) 300 (30)

Tobacco products
Drying, stripping 300 (30)
Grading and sorting lSOO(150) ,

Upholstering 1500 (150)

a Industry representatives have established this table of single illuminance values. Illuminance values for
specific operations can also be determined by using illuminance values for similar tasks and activities.

Color temperature of the light source is important for color matching.

Special lighting such that (i) the luminous area is large enough to cover the surface which is being
inspected and (2) the luminance is within the limits necessaq to obtain comfortable contrast conditions.
This involves the use of sources of large area and relatively low luminance in which the source luminance
is the principal factor rather than the illuminance produced at a given point.

Maximum levels - controlled system.

e Higher levels from local lighting may be required for manually operated cutting machines.
f
If color matching is critical, use illuminance of 3000 lx (300 fc).

Supplementarylighting should be provided in this space to produce the higher levels required for specific
seeing tasks involved.

Additional lighting needs to be provided for maintenance only.

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, Hump area (vertical) 200 (20)

Control tower and retarder area (vertical) 100 (10)
Head end 50 (5)
Body 10 (i)

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Ways 100 (IO)

Fabrication areas 300 (30)
Storage yards
Active 50 (5)c
Inactive 10 (1)

Select upper level for high speed conveyor systems. For grading redwood lumber 3000 lux (30 fc) is required.

Supplementary lighting may be required in some cases.

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Figure A2-3 Recommended Illuminance Values (maintained on the task) for Specific Industries

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Indoors
Paper m P - preparation
Groundwood mill grinder room 700 (70)
Beater room 300 (30)
Brown stock washers 500 (50)

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a Obtained with a combinationof general lighting plus specialized supplementary'lighting. Care should be taken to keep within the
recommended luminance ratios (see Figure 2 in RP-7). These seeing tasks generally involve the discrimination of fine detail for long
periods of time and under conditions of poor contrast. The design and installation of the combination system much not only provide a
sufficient amount of light, but also the proper direction of light, diffusion, color and eye protection. As far as possible it should
eliminate direct and reflected glare as well as objectionableshadows.

' The specular surface of the material may necessitate special considerationin selection and placement of lighting equipment, or
orientation of work.

These illuminances are not intended to be mandatory but are recommended practice to be considered in the design of new facilities.
For minimum levels for safety, see section 14.2 and Figure 15 in RP-7.All illuminancesare average maintained levels.

indicates vertical illuminance.

Refer to local governing body for lighting requirements.

The use of many areas in petroleum and chemical plants is often different h m what the designation may infer. Generally, the areas
are small, occupancy low (restricted to plant personnel), occupancy infrequent, and only by personnel trained to conduct themselves
safely under unusual conditions. For these reasons,illuminancesmay be different from those recommended for other industries,
commercial areas, educational facilities or public spaces.

Refer to FAA regulations for required navigational and obstruction lighting marking.

Localized general lighting.

' Obtained with a combination of general lighting plus supplementarylighting. Care should be taken to keep withiin the recommended
luminance ratios.
**
Maximum levels - controlled system.

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(This Annex is not part of the American National Visual Comfort Probability (VCP)
Standard and Practice ANSVIESNA RP-7-2007.)
The Visual Comfort Probability system for evaluating
glare from a lighting system was developed in the
ANNEX B United States in the 1960’s. The system was derived
PREDICTIVE METHODS FOR DETERMINING by combining the photometrics of the luminaries test-
VISUAL COMFORT PROBABILITY (VCP) AND ed and the size of various rooms with the discomfort
UNIFIED GLARE RATING (UGR) glare evaluations from a set of observations made by
average viewers. From a large data base of observa-
tions by test subjects, a series of formulae were gen-
One of the important factors in designing a lighting erated which could, with acceptable accuracy, repro-
system for an Industrial Facility - or any space - is duce the experimental results and calculate a VCP
glare control. This will have an impact on the percep- value for a given luminaire. The VCP number deter-
tion of comfort within the space and the degree to mined from the calculations is intended to represent
which the lighting system design is considered suc- the number of people, out of a total number of 100
cessful. Usually, we think of “glare” as something to (therefore, it becomes a percentage of the total), who
be avoided in the design of a lighting system because would consider the lighting system in the room to be
it creates discomfort, disability or both, for the observ- Comfortable from the standpoint of glare. It has been
er. There are, of course, situations in which glare is concluded from experimental data that a difference in
intentionally introduced. Examples include glare from VCP of five points or less is insignificant. Figure B-1
a security lighting system, which limits the visibility of shows a typical set of VCP values.
conditions within a secured facility or glare produced
by moveable lighting equipment in theatrical períor- Figure B-i. An example of a table of VCP values.
--``````-`-`,,`,,`,`,,`---

mances.
Room Luminaires Lengthwise Luminaires Crosswise
When glare is to be avoided, there should be some
means of predicting, during the design phase of a pro- W L 8.5 10.0 13.0 16.0 8.5 10.0 13.0 16.0
ject, what the effect of glare from the lighting system 20 20 78 82 90 94 77 81 89 93
will be BEFORE the lighting equipment is installed. 20 30 73 76 82 88 72 75 81 86
There have been attempts over the past forty years to 20 40 71 73 78 82 70 72 76 80
develop systems that will predict the effect of glare on 20 60 69 71 74 78 68 70 73 76
the observer. One system for predicting glare, devel- 30 20 78 82 88 92 77 81 87 92
oped in North America, is Visual Comfort Probability 30 30 73 75 80 85 72 74 79 84
(VCP). In European countries, there have been sev- 30 40 70 72 75 78 69 71 74 77
30 60 68 69 71 74 67 69 70 73
eral systems over the last 20 to 30 years. In an
30 80 67 69 69 72 67 68 68 71
attempt to rationalize these various systems, the
Commission Internationale de I’Eclairage (CIE), in 40 20 79 82 87 92 79 82 87 91
1995, proposed the Unified Glare Rating (UGR) sys- 40 30 74 76 79 84 73 75 78 83
40 40 71 72 74 77 70 71 73 76
tem, which tries to incorporatethe best features of the 40 60 72 68
68 69 70 69 69 71
various European national glare prediction methods 40 80 67 68 68 70 67 68 67 69
into one universal system. 40 100 67 68 67 69 67 67 66 68
60 30 75 76 79 83 74 76 78 82
At the present time, VCP and UGR seem to be the 60 40 71 72 74 76 71 72 73 76
world’s two most accepted glare prediction systems. If 60 60 69 69 69 71 68 69 68 70
UGR is to become the world standard in this area, it is 60 80 68 68 67 69 67 68 66 68
in our best interests to understand the system. 60 100 67 67 66 67 67 67 65 66
100 40 74 75 75 78 74 74 75 77
A brief description of each of these two systems fol- 100 60 71 71 71 72 71 71 70 72
lows to introduce the concepts, and limitations, of 100 80 70 70 68 69 70 69 67 69
each. The calculations used in predicting accep- 100 100 69 68 66 67 69 68 66 67
tance of a lighting system in each of the systems are
This example is for use when the units of length and illuminance are
included for information only since the information the foot (ft) and footcandle (fc). VCP values are identical if units of
can be made available by the manufacturersof light- length and illuminance are the meter (m) and the lux (lx).
ing equipment as a single rating number where it is
Wall Reflectance, 50%; Effective Ceiling Cavity
relevant to the applications. For those who may wish Reflectance, 80%; Effective Floor Cavity
to investigate this subject in more depth, the docu- Reflectance, 20%; Luminaire No. 000; Workplane
ments included in the References will be a good Illuminance, 100 fc
place to start.
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In order to allow for a comparison of several types of Unified glare Rating (UGR)
luminaries in different types of room configurations, a
set of criteria was developed and these criteria are the In 1995, the Commission Internationalede I’Eclairage
only ones for which experimental data are available (CIE) published a document with its proposed glare
and, therefore, the only ones for which it can be said, rating system, the Unified Glare Rating (UGR). The
with any certainty, that the VCP evaluation system system was developed from a document published
works. The standard conditions adopted for VCP cal- earlier by CIE, Publication#55, in which a Glare Index
culations are: Formula was introduced. This formula was based on
a study of the then current research and practice.
The initial illuminance shall be 1O00 Ix (1O0 fc) There has been some difficulty in making this system
Room surface reflectances shall be: work based on the calculation procedure that was
ceiling cavity 80% included in CIE Publication #55. Therefore, the
walls 50% process has been somewhat simplified, primarily by
floor cavity 20% the omission of reference to vertical illuminance at the
observers eye.
Mounting heights above the floor: 2.6; 3; 4; and 4.9 m
(8.5; 1O; 13 and 16 ft.) All of the formulae used by European members of CIE
A range of room dimensions to include square, long for a glare rating technique follow roughly the same
narrow and short wide rooms form:
A standard layout involving luminaries uniformly dis-
tributed throughout the room Formula 1
An observation point 1.2 m (4 ft) from the rear wall of
the room and 1.2 m (4 ft) above the floor
A horizontal line-of-sight directly forward
A vertical limit to the field of view corresponding to an where:
angle of 53” above, and directly forward from, the
observer. C, = a constant determined experimentally
C, = a constant determined experimentally
The system was validated using lensed, direct distrib- fm,, = background luminance of the room
ution, flat bottom fluorescent luminaries only. For this flurninaire = luminance of a luminaire

reason, it should not be used with small source

incandescent or fluorescent, suspended HID, indirect As is the case with VCP, the lighting related factors
or luminous ceiling lighting systems. which are prominent in the UGR formula are back-
ground luminance, average luminance of the luminar-
By consensus, discomfort glare will not be a problem ies (light sources), the solid angle subtended by each
when all of the following conditions are met by the of the individual luminaries from the observer’s eye

--``````-`-`,,`,,`,`,,`---
lighting system: and the Guth Position Index. All of these factors are
calculated the same way for either the VCP or the
The VCP is 70 or more; UGR methods with the exception of background lumi-
The ratio of maximum luminance (luminance of the nance. The UGR method uses background lumi-
brightest6.5-cm2[ l -in2])to the average luminaire lumi- nance of the room surfaces within the field of view,
nance does not exceed 5:l at vertical angles of 45, excluding the luminaries, while average luminance of
55,65,75 and 85” above a vertical line (nadir) through the total field of view, including luminaries, is used in
the luminaire in both the cross-wise and the length- the VCP calculation. This may be seen later in the cal-
wise directions; culations. In addition, the luminaire and observer posi-
The maximum luminances of the luminaire, in both tions are determined in a manner very similar to the
the cross-wise and length-wise directions, does not VCP method.2
exceed the following values:
CIE believes that the current Unified Glare Rating for-
mula contains the best parts of the various systems
VERTICAL ANGLE MAXIMUM recently used in the European countries to predict dis-
ABOVE NADIR LUMINANCE comfort glare. The scale of the system is an “interval
(degrees)
- (cd/m2) scale” where the difference between the numbers are
45 771O glare differences which can be seen by an observer.
55 5500 Therefore, in the UGR method, a difference of one
65 3860 number on the scale is significant. The scale used to
75 2570 indicate the level of glare determined by these formu-
a5 1695 lae is the same as the scale used in the British system

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for nearly 30 years. It has been found acceptable and Is there a correlation between the two systems?
there seemed to be no reason to change a working There could be. The glare sensitivity of any given indi-
model. The practical range of the UGR scale is vidual is vague, at best. This is borne out by the large
between 10 and 30. Unlike the North American VCP standard deviations and the poor reproducibilityof the
scale, a lower number on the UGR scale indicates a glare observations within any group.4 At least one
system with less glare. (See Figure B-2.) study has been performed which compared calcula-
tions of VCP and UGR for five lighting situations. The
result is indicated in Figure 8-3 and shows that a
RATING VALUE SUGGESTED UGR curve can be generated to relate VCP to UGR. The
dotted lines on the graph indicate one set of common
Just Intolerable 31 points in the calculations for both VCP and UGR. As
Uncomfortable 28 can be seen, a VCP value of 70 translates to a UGR
Just Uncomfortable 25 value of 19. This was the case for each of the five cal-
Unacceptable 22 culations made for this study and the curve shown on
Just Acceptable 19 the drawing is the result of those calculations. Studies
Perceptible 16 have indicated that UGR has a reasonable record of
Imperceptible 10 success in predicting the sensation of glare.

Figure B-2. Categories of discomfort glare and

equivalent UGR values from Akashi, et al?

Ageneral means of interpretingthis scale has been sug-

gested using research performed in Japan (see Figure
B-2). Generally speaking, it is felt the range of accept-
able glare ratings for the UGR system is between 10
and 20 for offices with the lower numbers being more
acceptable. Figure B-2 indicates glare ratings of 1O are
--``````-`-`,,`,,`,`,,`---

imperceptible while glare ratings of 22 are unaccept-

able. A UGR number of 20 has been determined to be
the limiting glare value for offices. The results of these
experiments suggest the number of luminaries in the
field of view may influence the ratings. Researchers also VCP
found that untrained observers seemed to rate lighting Figure 8-3.The relationship between VCP and the
systems as being more glaring than trained lighting UGR,discomfort glare
observers. That is, they tended to assign higher UGR
number and lower VCP numbers. It should be noted More work is required before a correlation between
that other researchers have questioned the interpreta- the two systems can be formalized.
tion of the observations reported by Akashi, et a1.3
VCP calculation^:^
There are some limitations to the UGR system, as
there are to the VCP system. At this time, it is not To calculate VCP, several intermediate calculations
known whether the UGR system will work satisfacto- must be made. It is necessary to determine the position
rily for luminous ceiling or indirect lighting systems. index and the average luminance of each luminaire, the
More research is needed in these areas. The data function Q, which is determined from the solid angle of
used to validate the UGR system was limited, much each of the luminaries at the position of the observer,
as was the VCP research, to sources which have a and an index of sensation M. The Discomfort Glare
maximum solid angle at the observers eye of 0.1 Rating (DGR) is then determined from a summation of
steradian (a source of about 1 m2viewed from a dis- all of the values of M. Finally, the VCP will be.deter-
tance of 3 m)‘. In addition, the UGR system should not mined using the DGR. It is fairly obvious that this is not
be used for the present, at least, for sources smaller a calculation to be entered into casually. The various
than the equivalent of an incandescent downlight. formulae are listed here only for information.

Which System is Better? The Position Index is a value, P, determined for each
luminaire by the following formula. It is a means of
At this time, it may be too early to tell. There are limi- weighting each of the luminaries in the field of view to
tations to both systems. The scales produced by the account for the fact that not all luminaries will impact
two systems are opposed to each other. A high num- the observer in the same way. As the luminaire is
ber in the VCP system indicates low glare while a low moved further from the line of sight, the impact upon
number in the UGR scale indicates less glare. the observer’s impression of glare is reduced.
66
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-

Formula 2 (See Figure 8-5 for a description of o.)

P = exp[(35.2-0.31889a-1.22e-~" 9)1~-3
ß +(21+ 0.26667a - 0.002963a2)1O-'ß2]
where:
a = angle from a vertical line directly ahead of the
viewer's line of sight and a line from the observer to
the luminaire in a plane perpendicular to the lumi-
naire. (See Figure 8-4.)
p = angle between the line of sight at the observer and
a line to the luminaire center from the observer.

Figure B-5 Solid angle oabcdefgvisible from the

observer's location includes the bottom surface, one
end and one side surface of the drop diffuser on the
fluorescent luminaire.

The average luminance in this formula, F, is called L,

in some other formulae, including the UGR formula,
which follows later in this Annex.
Observer
A function Q has been developed which is used in the
calculation of VCP:
Figure B-4 Geometry defining position index as used
in VCP and UGR methods.
Formula 4
This data is also available in the form of a table, which Q = 20.40,, + 1.520:'~ - 0.075
would be, obviously, a much easier way to obtain
where:
these values.
o,= the solid angle subtended at the observer by the
source (in steradians). The solid angle is equal to the
The average luminance for the entire field of view is
area of the luminaire (source) in m2(ft2) divided by the
found from the following Formula:
square of the distance from the observers eye to the
Formula 3
center of the luminaire (source) in m2(ft').
where:
After making these calculations, the values of P, F,
1,= average luminance of the walls (cd/m2) and Q are used to calculate the Index of Sensation, M
L, = average luminance of the floor (cd/m2)
for each of the luminaries in the field of view:
--``````-`-`,,`,,`,`,,`---

F, =
Lwww+ L , W , c
+ L'W' + L, 0 ,
1 4
Formula 5
0.50L,vQ
5 M, =
P,,Fv".44
L, = average luminance of the ceiling (cd/m2)
L, = average luminance of the source (cd/m2)
where Ls is the average luminance of the source (or
o,= solid angle subtended at the observer by the luminaire) being calculated in the direction of the
walls (in steradians) observer. The factor 0.50 in the numerator of the pre-
of= solid angle subtended at the observer by the ceding Formula allows for the use of the units indicat-
floor (in steradians) ed in these calculations.
o,= solid angle subtended at the observer by the From the above information, a Discomfort Glare
ceiling (in steradians) Rating (DGR) can be calculated using the following:
o,= solid angle subtended at the observer by the
source (in steradians) Formula 6
n = the number of the source being calculated (from
n=l to n=n).

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where: Formula 10*

n = the number of luminaries in the field of view
M, = index of sensation for the ‘7th” source (with the
last source being equal to “n”).

The calculation for the summation (C) of all of the *There are many forms of this formula in print today.
“Indices of Sensation” (M,) requires a separate calcu- This one has been selected for use here because it
lation for the Index of Sensation for each of the lumi- seems to speak with the most authority for the CIE.
naries in the field of view.
References:
Finally, we are ready to make the calculation of VCP
using the following formula: I.CIE Publication # I 17-1995., 1995, Discomfort
--``````-`-`,,`,,`,`,,`---

Glare in Interior Lighting, Vienna, Austria:CIE

Formula 7
2. van Bommel, Ir. W.J.M, A new international sys-
tem for glare evaluation for interior lighting.
VCP = - e
3. Mistrick, R., and Choi, A-S., A Comparison of the
UGR Calculations’: Visual Comfort Probability and Unified Glare Rating
Systems, J. of the /ES 28 (no2) 94-101
As will be remembered, the background luminance in
the VCP calculation is the value F, and it includes the 4. Einhorn, H., Unified glare rating (UGR): Merits and
luminance of each of the luminaries. In the UGR for- application to multiple sources, CIBSE, London,
mula, the background luminance of the space is Lighting Research and Technology, 1998
determined by the formula:
5. IESNA, 2000, IESNA Lighting Handbook, 9lh
Formula 8 Edition, Chap 3, New York, NY

L h --1
E 6. 1991, 1st International Symposium on Glare,
?T Symposium Proceedings, Lighting Research Office
(formerly Lighting Research Institute), Electric Power
where E, is the indirect illuminance at the eye of the Research Institute, Palo Alto, CA.
observer.

In the CIE method for UGR, Ei may be determined in

several ways, but a simplified approach is to assume
the indirect illuminance (E,) at the observer’s eye will
be equal to the indirect illuminance on the walls of the
room. This method seems to work well for general
lighting systems with a uniform layout of luminaries. It
is unclear whether this will be true for non-uniform
luminaire layouts.

The calculation of the luminaire luminance divides the

average luminous intensity in the direction of the
observer’s eye by the area of the luminaire, A:,

Formula 9

Using these calculations, the values for and the Guth

Position Index P as determined earlier, the UGR may
be calculated by use of the formula:

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(This Annex is not part of the American National The method does have limitations. The illuminance
Standard and Practice ANSI/IESNA RP-7-01.) computed is an average value that is representative
only if the luminaries are spaced to obtain reasonably
uniform illuminance. The average illuminance deter-
ANNEX C mined by the method is defined to be the total lumens
AVERAGE ILLUMINANCE CALCULATION: THE reaching the horizontal workplane divided by the area
LUMEN METHOD of the workplane. The average value determined this
way might vary considerably from that obtained by
averaging discrete values of illuminance at several
Choosing a Calculation Method points. The method assumes that room surfaces are
diffuse, the illuminance on each surface is uniformly
Lighting calculations are performed during the design distributed over that surface and that the room is
process to obtain information about lighting system empty.
performance.A designer can use the results of calcu-
lations to choose between design alternatives or to The workplane is positioned at the height of the visu-
refine a particular design. Lighting calculations are al task. For example, for desk tasks the height is typ-
mathematical models of the complex physical ically assumed to be 0.76 m (2.5 ft.) above the floor.
processes that occur within a lighted space. Since In a space such as a jet aircraft factory, it might be
these models can never be accurate in every detail, placed at the wing height of the aircraft.
the computations are approximations of real situa-
tions. Average Illuminance Equation

The simplest lighting calculation can be performed by The equation for the illuminance in a space is:
hand, whereas the more advanced methods require @(roTa,)x CU x LLF
the use of a computer. More advanced methods gen- E, =
erally provide more accurate information. (Accuracy is Av
defined here as the degree to which the calculations where:
agree with reality.)
E, = average maintained illuminance
The type of informationthat is desired about a lighting on the workplane
system and the complexity of the lighting condition @(TOTAL)= total system lamp lumen output

--``````-`-`,,`,,`,`,,`---
being analyzed determine which calculation method is CU = luminaire coefficient of utilization
best applied to the problem. The aspects that must be LLF = light loss factor
evaluated in determining the lighting analysis model A, = area of the workplane
to use are the following:

Information desired These terms will be explored in more detail. See also
Equipment choice the calculation worksheet, Figure C-1.
Equipment number and placement
Space characteristics Workplane illuminance (€,)is the average main-
tained luminous flux striking the workplane per unit
It is the responsibilityof the designer to determine and area of workplane.
use the most appropriate calculation methods for an
application, either a simple average illuminance Total System Lamp Lumen Output (@,,)-refers to
method or a more complex method to calculate illumi- the number of initial lumens produced by all lamps
nance at a specific point. within the luminaries that are lighting the space. The
lamp manufacturer’s published lumen rating is used
The Lumen Method for this calculation.

The Lumen Method described here is the simple aver- For example, an application is using 10 recessed flu-
age illuminance calculation method, which can be orescent luminaries. Each luminaire has three 32W
applied to interior spaces where a general uniform T8 lamps. The manufacturer’s data on the lamp
lighting system is required. It is a useful tool in two shows that the initial lumen output of the lamp is 2900
ways; it allows the calculation of the average illumi- lumens. Thus, the total lamp lumen output ((I ) in
nance when given the number of luminaries to be the space is
used in the space, or it can be used to find the num-
ber of luminaries required, given the desired average ),@
,(,,, = 10 luminaries x 3 lamps/luminaire x 2900
illuminance. IumensAamp = 87,000 lumens

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 ANSI / IESNA RP-7-01
GENERAL INFORMATION

Project identification:
(Give name of area and/or building and room number)

Average maintained illuminance for design:- lux or Lamp data:

:- footcandles
Type and color:
Luminaire data:
Number per luminaire:
Manufacturer:
Total lumens per luminaire:
Catalog number:

SELECTION OF COEFFICIENT OF UTILIZATION

Step 1 : Fill in sketch at right -T

Step 2: Determine Cavity Ratios

‘-T hCCJ-

1=

=-
* e--% ’RC
w- -
- -4-
Room Cavity Ratio, RCR =
Ceiling Cavity Ratio, CCR =
-- WORK-PLANE--

Floor Cavity Ratio, FCR =

es-% ,eæ-% A
hFC O-

Step 3:Obtain Effective Ceiling Cavity Reflectance @=) pcc= -

Step 4: Obtain Effective Floor Cavity Reflectance (pFc) PFC e -
Step 5: Obtain Coefficient of Utilization (CU) from Manufacturer’s Data CU= -
SELECTION OF LIGHT LOSS FACTORS
Nonrecoverable Factors Recoverable Factors
LuminaireAmbient temperature factor Lamp lumen depreciation factor (LLD)
Heat extractionthermal factor Luminairedirt depreciationfactor (LLD)
Voltage to luminaire factor Room surface dirt depreciationfactor (RSDD)
Ballast factor (BF) Lamp burnout factor (LBO)
Ballast lamp photometer factor
Equipment operatingfactor
Lamp position (tilt) factor
Luminairesurface depreciationfactor
Total light loss factor, LLF (product of individual factors above) = -

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CALCULATIONS
(Average Maintained Illuminance)
(Illuminance) x (Area)
Number of Luminaires =
(Lumens per Luminaire) x (CU) x (LLF)

(Number of Luminaires) x (Lumens per Luminaire) x (CU) X (LLF)

Illuminance =
(Area)

Calculated by: Date:

Fia. 9-20. Avernnn illiiminnnrin calci ilntinn shed

Figure C-l. Average illuminance calculation worksheet.

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 ANSI / IESNA RP-7-01

Luminaire Coefficient of Utilization (CU)-gives the Or:

fraction of lumens that reach the workplane, directly The areas in the first equation are the total vertical
from the light sources and from interreflections. The and horizontal surface areas within the room cavity,
CU takes into account the efficiency of the luminaire which is the space between the luminaries and the
and the impact of the luminaire distribution and the workplane.A room may have up to three different cav-
ities (see Figure C-2). The portion of the room that is
Floor Cavity Height x ( Length + Width)
FCR = 5 above the luminaries is called the ceiling cavity, and
Length x Width that portion below the workplane is the floor cavity.

Ceiling Caviíy Height x (Length + (Width)

CCR = 5
Length x Width
room surfaces in its derivation. Thus, the number of Luminaire piane
plane J
lumens produced by the lamps, multiplied by the CU,
determines the number of lumens that reach the
workplane. Four factors influence the CU:

The efficiency of the luminaire

(b) The luminaire distribution
(c) The geometry of the space
(d) The reflectances of room surfaces

CU values are listed in tables for different room

geometries and room surface reflectances. Each Figure C-2. The space may be divided into as many
luminaire has its own CU table specific to that lumi- as three cavities.
naire’s light distribution and efficiency. Factors (a) and
(b) are, therefore, included in all values found in a CU If the luminaries are recessed or surface mounted,
table. Their values are tabulated for various surface there is no ceiling cavity. if the workplane is at the floor
reflectancesand room cavity ratios (RCRs).The RCR level there is no floor cavity.
is five (5) times the ratio of total vertical surface area
to total horizontal surface area within the room cavity It is critical to consider only the wall surface area that
and therefore indicates the relative space proportions. is within the room cavity as the vertical surface area in
determining the RCR. The horizontal surface area
To find the RCR, either of the following equations can refers to the area of the workplane and the luminaire
be used: plane and is the same as two times the floor area.
where: The only other room parameters that are needed to
obtain a CU value are the room cavity reflectances,
VSA = the sum of the vertical surfaces within the room which may not be equal to the actual room surface
cavity. This is the sum of the wall areas above the reflectances. Since the Lumen Method considers
working plane and below the luminaries. what occurs only within the room cavity, the ceiling
and floor cavities are replaced with their effective
HSA = the sum of the working plane and the luminaire reflectances. Effective reflectances model the manner
plane areas in which these cavities reflect light.

Recoverable Factors Nonrecoverable Factors

Lamp lumen depreciation factor (LLD) Luminaire ambient temperature factor
Luminaire dirt demeciation factor íLDD) Heat extraction thermal factor
I Room surface dirt demeciation factor íRSDDì I Voltage to luminaire factor I
Lamp burnout factor (LBO) Ballast factor (BF)
Ballast lamp photometer factor
Equipment operating factor
Lamp position (tilt) factor
Luminaire surface depreciation factor
--``````-`-`,,`,,`,`,,`---

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 ANSI / IESNA RP-7-01

For example, in an industrial application where the operating factor Lamp position (tilt) factor Luminaire
luminaries are suspended from the ceiling, the space surface depreciation factor
between the luminaries and the ceiling is the ceiling
cavity. Because light that enters the ceiling cavity may A total light loss factor of 0.75 might be applied to
reflect off more than one surface before exiting the many well-maintained commercial buildings having a
cavity, the effective reflectance of the ceiling cavity is clean environment. This means that 25 percent (100
generally lower than the actual ceiling reflectance. For minus 75 percent) of the luminous flux that might oth-
a floor cavity, where the walls are usually of higher erwise reach the workplane is lost due to ballast fac-
reflectance than the floor, the effective reflectance tor, dirty luminaries, rooms surfaces, and aged lamps.
may be higher or lower than the actual floor In a dirty manufacturing facility the percentage lost
reflectance, depending on the space dimensions. would be higher.

To find the effective reflectance of a floor or ceiling Area of Workplane ( A w p ) I sthe area of the entire
cavity, it is necessary to first find the floor cavity ratio workplane, which is typically the same as the floor
(FCR) or ceiling cavity ratio (CCR). The equations are area. The Lumen Method computes an average illu-
identical to that for the room cavity ratio, except that minance over the entire area of the space. In reality,
the height of the walls within the cavity is used as the the illuminance will be greatest near the center of the
cavity height. area and slightly less toward the walls for a given uni-
form layout of luminaries.
The only other information necessary to find the effec-
tive cavity reflectances are the cavity surface Calculating the Number of Luminaries
reflectances. The surface that is opposite the opening
to the cavity is called the cavity base. The base It is important to know not only how to calculate the
reflectance, the wall reflectances, and the cavity ratio illuminance from a specific number of luminaries in a
determine the effective cavity reflectance. Knowing space, but also how to determine the required number
these pieces of information it is possible to find the cav- of luminaries to meet a desired illuminance. The num-
ity reflectance (see IESNA Lighting Handbook, 9th ber of luminaries required is calculated by rearranging
Edition, for detailed information on cavity reflectances.) the Lumen Method equation.
Number of Luminaires =
Light Loss Factor (LLï,-Since the design objective
usually is maintained illuminance, a light loss factor 4, x E,,
must be applied to allow for the estimated depreciation lumens i lampx lampshminairesx CU x LLq,,,,,)
in lamp lumens over time, the estimated losses from
dirt collection on the luminaire surfaces (including
lamps), and other factors that affect luminaire lumen

--``````-`-`,,`,,`,`,,`---
output over time. Some differences prevail from initial
operation of the system; others change with time. It is
important to consider these losses to accurately reflect
the system’s performance in the real environment.

Light loss factors are divided into two groups: recover-

able and non-recoverable. (See Figure C-3.)
Recoverable factors can be affected by maintenance,
such as cleaning and relamping luminaries, or by clean-
ing or painting room surfaces. Nonrecoverable factors
are those attributed to equipment and site conditions
and cannot be changed with normal maintenance. The
total LLF is simply the product of the individual factors.
For more information on the various factors, see the
IESNA Lighting Handbook, 9th Edition, 2000.

Recoverable Factors Nonrecoverable Factors

Lamp lumen depreciation factor (LLD) Luminaire
ambient temperature factor Luminaire dirt deprecia-
tion factor (LDD) Heat extraction thermal factor Room
surface dirt depreciation factor (RSDD) Voltage to
luminaire factor Lamp burnout factor (LBO) Ballast
factor (BF) Ballast lamp photometer factor Equipment

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 i

,
--``````-`-`,,`,,`,`,,`---

IFS

Illuminating Engineering Society of North America

120 Wall St. 17th Floor New York, NY 10005
http:/lwww.iesna.org

$40.00 Order # RP-7-01 ISBN # 0-87995-176-1

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