ILLUMINATION PRACTICES
FOR DIPLOMA IN ELECTRICAL
ENGINNERING
PRESENTED BY :JYOTIRMOY ROY
CODE:EEPE 305/1
UNIT=5
INTERIOR LIGHTING DESIGN
• STANDRAD ILLUMINATION LEVEL FOR VARIOUS INTERIOR
APPLICATION AS PER IS 3646
• PDF WILL BE GIVEN REGARDING IT
SPACE HIGHT RATIO
• Space to height ratio is the ratio of space between luminaires (S) to
their height above the working plane (Hm). Manufacturers specify the
recommended space to height ratio (SHR) for each of their luminaires.
Typically, a recommended space to height ratio (SHR) is 1 : 2.
• The Spacing to Mounting Height Ratio (SHR) is the spacing between
luminaires divided by their height above the horizontal reference
plane. It affects the uniformity of illuminance on that plane
UTILIZATION FACTOR
• The utilization factor or use factor is the ratio of the time that a piece
of equipment is in use to the total time that it could be in use. It is
often averaged over time in the definition such that the ratio becomes
the amount of energy used divided by the maximum possible to be
used. These definitions are equivalent.
light loss factor overall uniformity
• LLF = .85 = RSDD x LDD x BF x LLD
• LLF (Light Loss Factor) is the product of several factors, each
depreciating light output at certain point in time in the future
compared to initial light output. LDD takes into account the dirt
accumulation on the lens or other components of the luminaire that
may reduce light output.
•LLF = .85 = RSDD x LDD x BF x LLD
•LLF includes:
• .98 RSDD (room surface dirt depreciation) and LDD (luminaire dirt depreciation)
• 1.0 (ballast/driver) factor
• .87 LLD* (lamp lumen depreciation)
• LLF (Light Loss Factor) is the product of several factors, each depreciating light output at certain point in time in the future
compared to initial light output.
• Recoverable factors typically considered in these calculations are:
• Room Surface Dirt Depreciation (RSDD)
• RSDD weighs the changes in the cleanliness of room surfaces from which light bounces off. These days it is common to
consider RSDD negligible in most spaces.*
• Luminaire Dirt Depreciation (LDD)
• LDD takes into account the dirt accumulation on the lens or other components of the luminaire that may reduce light output.
• Because most of the environments in which luminaires are placed are clean (interior rooms) and are assumed to be well-
maintained, the assumption is:
• RSDD x LDD = .98
• Lamp Lumen Depreciation (LLD)
• The L70 metric recognizes the fact that lumen output depreciates over time and establishes LEDs’ rated life as the point at which
lumen depreciation has reached 30% (LLD=0.70). Since this point is likely to be years in the future, using L70 as a factor to
design around may lead to significant, initial over-lighting.
• A more accurate mean value for LEDs assumes a point in time that approximates the mean life of familiar sources (T8 and T5
fluorescent) that have traditionally been defined as 40% of their rated life. Conservatively, LEDs at a comparable time have lost
about 12-13% of their light output.*
• LLD = .87 - .88
• LLF = .98 x .87 = .85
Glare index
• The CIBSE glare index is a system for the evaluation of discomfort
glare defining two methods of calculation: The calculation of the glare
index based on a formula. The finding of the index from tables based
on the photometric data as supplied by the luminaire manufacturer.
CRI ,LIGHT POWER DENSITY (LPD);ECBC
•CRI:Color Rendering Index (CRI) is a way to measure a light
source's distinctive attributes. It is an assessment of how the
light source shows object colors "naturally" when compared
to a familiar basis of reference, either incandescent light or
daylight.
•Lighting Power Density (LPD) is a lighting power requirement defined
in North America by the American National Standards Institute (ANSI),
American Society of Heating, Refrigerating and Air-Conditioning
Engineers (ASHRAE), and the Illuminating Engineering Society of
North America (IESNA) Lighting subcommittee.
•Lighting Power Density technically represents the load of any lighting
equipment in any defined area, or the watts per square foot of the
lighting equipment. However, in the lighting industry it is often
associated with the lighting power allowance (LPA) permitted by the
building energy code in question.
•The Oregon Department of Energy defines lighting power density as
"The maximum allowable lighting density permitted by the code. It is
expressed in watts per square foot for a given occupancy/space type
•The Energy Conservation Building Code (ECBC) set minimum
energy performance standards for commercial buildings.
LIGHTNING CALCULATION METHOD
• For a commercial lighting design to be successful, each area of the
building must have a sufficient level of light to allow users to perform
their tasks. Thus, to determine the desired illumination, proper
lighting calculations are to be made.
• There are a number of methods employed for lighting calculations,
the three main methods are given as follows −
• Watt per Square Meter Method
• Lumen Method
• Point to Point Method
Watt per Square Meter Method,Lumen Method,Calculation
• The watt per square meter method is fundamentally a rule of thumb method. This method of lighting
calculation comes in handy when doing a quick calculation or double-check. It entails allocating watts per
square metre of the area to be illuminated in accordance with the desired illumination, based on an
average figure of overall system efficiency.
• The lumen method, also called the light flux method, is the method employed for lighting calculation is
applicable to those cases where the sources of light are such as to produce an approximate uniform
illumination over the working plane or where an average value is required.
• CALCULATION:In lumen method of lighting calculation, the total lumens output is determined from the size
of the lamp or lamps employed and from their efficiency. Now, the lumens received on the working plane
are determined by multiplying the total lumens output from the source with the coefficient of utilization
• In the case, when the lamps and surroundings are not perfectly clean, then in the determination of the
lumens received on the working plane, the depreciation factor or maintenance factor should be included.
• Thus, the lumens received on the working plane is given by,
• Lumensreceived=Numberoflamps X Wattageofeachlamp X Efficiencyofeachlampintermsoflumensperwatt
X(Coefficientofutilization / Depreciationfactor)
• Also, the lumens received on the working plane may be given as,
• Lumensreceived=Numberoflamps×Wattageofeachlamp×Efficiencyofeachlampintermsoflumensperwatt×Coe
fficientofutilization×Maintenancefactor
POINT TO POINT METHOD
• The inverse square law method, also known as point-to-point method, is applicable where
the illumination at a point due to one or more sources of light is required. Though, the
candle power of the sources in the particular direction under consideration being known.
• If a polar curve of a lamp and its reflector giving the candle power of the lamp in different
directions is known, then the illumination at any point within the range of the lamp can be
determined from the inverse square law.
• In case, when two or more than two lamps are illuminating the same working plane, the
illumination due to each lamp can be calculate and added by this method. However, this
method is not much used due to its complications and heavy applications.
• http://www.electrical-knowhow.com/2012/12/point-by-point-method-for-lighting.html
• maths
RESIDENTIAL COMPLEX
• Good lighting design turns a house into a home. It enhances the interior design and architecture, and should
be designed to reflect how the resident lives in the space. A house can have the most beautiful interior
design and stunning architecture, but if the lighting is wrong it simply won’t feel like a home.
• Factors to Consider in Interior Lighting Design
• General Interior Lighting in Past and Present. ...
• Lamps for Interior Lighting. ...
• Luminous Efficacy Consideration. ...
• Life of the Lamps Consideration. ...
• Percentage Lumen Depreciation Consideration. ...
• Color of the Lamp Lumens Consideration. ...
• Ballasts Consideration.
COMMERICAL COMPLEX
• T5, compact fluorescent lights and LED light fixtures are commonly
used in commercial buildings: Tubular fluorescent lights – usually set
into ceilings, frosted lens covering, 1-4 bulbs, long lasting and energy
efficient
INDUSTRIAL PERMISES
• environment, around 500 LUX is needed. In the workshop area where
detailed work is done the recommended level is 500-700LUX. For
spaces like the operation theatre of the hospital, the LUX level should
be around 1000
•END UNIT
