Designation: C 1060 – 90 (Reapproved 1997)e1

Standard Practice for

Thermographic Inspection of Insulation Installations in
Envelope Cavities of Frame Buildings1
This standard is issued under the fixed designation C 1060; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

e1 NOTE—Keywords were added editorially in May 1997.

1. Scope caution should be taken in the handling of any cryogenic

1.1 This practice is a guide to the proper use of infrared liquids or pressurized gases required for use in this practice.
imaging systems for conducting qualitative thermal inspections Specific precautionary statements are given in Note 1 and Note
of building walls, ceilings, roofs, and floors, framed in wood or 3.
metal, that may contain insulation in the spaces between 2. Referenced Documents
framing members. This procedure allows the detection of
cavities where insulation may be inadequate or missing and 2.1 ASTM Standards:
allows identification of areas with apparently adequate insula- C 168 Terminology Relating to Thermal Insulating Materi-
tion. als4
1.2 This practice offers reliable means for detecting sus- E 1213 Test Method for Minimum Resolvable Temperature
pected missing insulation. It also offers the possibility of Difference for Thermal Imaging Systems5
detecting partial-thickness insulation, improperly installed in- 3. Terminology
sulation, or insulation damaged in service. Proof of missing
insulation or a malfunctioning envelope requires independent 3.1 Definitions—Definitions pertaining to insulation are de-
validation. Validation techniques, such as visual inspection or fined in Terminology C 168.
in-situ R-value measurement, are beyond the scope of this 3.2 Definitions of Terms Specific to This Standard:
practice. 3.2.1 anomalous thermal image—an observed thermal pat-
1.3 This practice is limited to frame construction even tern of a structure that is not in accordance with the expected
though thermography can be used on all building types.2,3 thermal pattern.
1.4 Instrumentation and calibration required under a variety 3.2.2 envelope—the construction, taken as a whole or in
of environmental conditions are described. Instrumentation part, that separates the indoors of a building from the outdoors.
requirements and measurement procedures are considered for 3.2.3 field-of-view (FOV)—the total angular dimensions,
inspections from both inside and outside the structure. Each expressed in degrees or radians, within which objects can be
vantage point offers visual access to areas hidden from the imaged, displayed, and recorded by a stationary imaging
other side. device.
1.5 The values stated in SI units are to be regarded as 3.2.4 framing spacing—distance between the centerlines of
standard. The inch-pound units given in parentheses are for joists, studs, or rafters.
information only. 3.2.5 infrared imaging system—an instrument that converts
1.6 This standard does not purport to address all of the the spatial variations in infrared radiance from a surface into a
safety concerns, if any, associated with its use. It is the two-dimensional image of that surface, in which variations in
responsibility of the user of this standard to establish appro- radiance are displayed as a range of colors or tones.
priate safety and health practices and determine the applica- 3.2.6 infrared thermography—the process of generating
bility of regulatory limitations prior to use. In particular, thermal images that represent temperature and emittance varia-
tions over the surfaces of objects.
3.2.7 instantaneous field of view (IFOV)—the smallest
1
This practice is under the jurisdiction of ASTM Committee C-16 on Thermal angle, in milliradians, that can be instantaneously resolved by
Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal
Measurement.
a particular infrared imaging system.
Current edition approved June 29, 1990. Published August 1990. Originally 3.2.8 masonry veneer—frame construction with a non-load
published as C 1060 – 86. Last previous edition C 1060 – 86. bearing exterior masonry surface.
2
ISO/TC 163/SC 1/WG N31E Thermal Insulation—Qualitative Detection of
Thermal Irregularities in Building Envelopes—Infrared Method, available from
American National Standards Institute, 1430 Broadway, New York, NY 10018.
3 4
Guidelines for Specifying and Performing Infrared Inspections, Infraspection Annual Book of ASTM Standards, Vol 04.06.
5
Institute, Shelburne, VT, 1988. Annual Book of ASTM Standards, Vol 03.03.

Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.

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 C 1060
3.2.9 minimum resolvable temperature difference Instantaneous field of view (IFOV) is an indicator of spatial
(MRTD)—a measure of the ability of the operators of an resolution. Appendix X1 explains how to calculate IFOV and
infrared imaging system to discern temperature differences how to measure MRTD.
with that system. The MRTD is the minimum temperature 6.2.1 Spectral Range—The infrared thermal imaging sys-
difference between a four-slot test pattern of defined shape and tem shall operate within a spectral range between 2 and 14 µm.
size and its blackbody background at which an average 6.2.2 Field of View (FOV)—The critical minimum dimen-
observer can discriminate the pattern with that infrared imag- sions for discriminating missing insulation in frame construc-
ing system at a defined distance. tion is two framing spacings wide and one framing spacing
3.2.10 thermal pattern—a representation of colors or tones high. Outdoors, it is typically convenient to view at least one
that indicate surface temperature and emittance variation. floor-to-ceiling height across and one-half that distance high.
3.2.11 thermogram—a recorded image that maps the appar- The FOV of the chosen imaging system should encompass
ent temperature pattern of an object or scene into a correspond- these minimum dimensions from the chosen indoor viewing
ing contrast or color pattern. distance, di, and outdoor viewing distance, do. For planning
3.2.12 zone—a volume of building served by a single purposes, the angular value of FOV may be calculated for
ventilation system. For buildings with natural ventilation only, either d (m) by the following equations:
the whole building shall be considered a zone with all interior FOVvertical $ 2 tan21~h/2d! (1)
doors open.
21
FOVhorizontal $ 2 tan ~w/2d! (2)
4. Summary of Practice
where:
4.1 This practice is a guide to the proper use of infrared
h 5 vertical distance viewed, m, and
imaging systems for conducting qualitative thermal inspections w 5 horizontal distance viewed, m.
of building walls, ceilings, roofs, and floors, framed in wood or
metal, that may contain insulation in the spaces between 7. Knowledge Requirement
framing members. Imaging system performance is defined in 7.1 This practice requires operation of the imaging system
terms of instantaneous field of view (IFOV) and minimum and interpretation of the data obtained. The same person may
resolvable temperature difference (MRTD). Conditions under perform both functions. The operator of the infrared imaging
which information is to be collected and compiled in a report system shall have thorough knowledge of its use through
are specified. Adherence to this standard practice requires a training, the manufacturer’s manuals, or both. The interpretor
final report of the investigation. This practice defines the of the thermographic data shall be knowledgeable about heat
contents of the report. transfer through building envelopes and about thermography,
including the effects of stored heat, wind, and surface moisture.
5. Significance and Use
7.2 The instrument shall be operated in accordance with the
5.1 Although infrared imaging systems have the potential to published instructions of the manufacturer.
determine many factors concerning the thermal performance of
a wall, roof, floor, or ceiling, the emphasis in this practice is on 8. Preferred Conditions
determining whether insulation is missing or whether an 8.1 The criterion for satisfactory thermal conditions is the
insulation installation is malfunctioning. Anomalous thermal ability to distinguish framing members from cavities. Appen-
images from other apparent causes may also be recorded as dix X2 gives some guidelines for determining whether the
supplemental information, even though their interpretation weather conditions are likely to be suitable.
may require procedures and techniques not presented in this
practice. 9. Procedure
9.1 Preliminary Inspection—A preliminary thermographic
6. Instrumentation Requirements inspection may be performed to determine whether a thorough
6.1 Environmental Factors—The environment has a signifi- inspection, and report, is warranted.
cant impact on the heat flow through the envelope. As a result, 9.2 Background Information—Prepare for the report by
the requirements on thermal imaging instrumentation vary with collecting information on the building. In order to evaluate the
the interior to exterior air temperature gradient for both interior structure, collect the following preliminary data where practi-
and exterior inspections and also vary with wind speed for cal and necessary:
exterior inspections. 9.2.1 Note each type of building cross section, using visual
6.2 Infrared Imaging System Performance—The ability of inspection, construction drawings, or both, to determine what
an observer to detect thermal anomalies depends on the thermal patterns to expect.
imager’s powers of thermal and spatial resolution. The practi- 9.2.2 Additions or modifications to the structure.
cal test for these qualities is whether the operator can distin- 9.2.3 Thermal problems reported by the building owner/
guish the framing from the envelope cavities under the occupant.
prevailing thermal conditions with the infrared imaging system 9.2.4 Note differences in surface materials or conditions that
at a distance that permits recognition of thermal anomalies. For may affect emittance, for example, metallic finishes, polished
planning an equipment purchase or a site visit, the following surfaces, stains, or moisture. Such differences in emittance
qualities may be considered: The minimum resolvable tem- cause thermal patterns that are independent of temperature
perature difference (MRTD) defines temperature resolution. differences.

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 C 1060
9.2.5 Orientation of the building with respect to the points uniformly lighter areas between the framing lines, representing
of the compass. the insulation. As seen from the cool side of the construction:
9.2.6 Heat sources, such as light fixtures, mounted in or the framing lines are light. The areas containing insulation are
close to the exterior construction. uniformly dark.
9.3 Performing On-Site Equipment Check and Settings:
NOTE 1—Caution: Metal framing with no insulation may fit this
9.3.1 Set the instrument gain or contrast to allow the description. See Note 2.
observer to distinguish a framing member from the envelope NOTE 2—Metal framing conducts heat better than both air and insula-
area around it. In addition, set the imager’s sensitivity so that tion. If insulation is present, the thermal contrast between metal framing
any anomalies or areas to which they are referenced are not in and the spaces between may be very strong. Independent verification may
saturation (maximum brightness or white) or in suppression be needed for metal-framed buildings to establish typical patterns for
(minimum brightness or black) on the display. insulated and uninsulated areas.
9.3.2 Verify proper operation of the recording system, if 10.2.2 Insulation Missing Completely—As seen from the
any. warm side of the construction: light parallel lines, representing
9.3.3 Make a sketch or photograph of each envelope area the framing; darker areas between the framing lines, represent-
with references for locating framing members. ing the empty space between framing members. Convection
9.4 Performing the Inspection: may be visible in vertical framing, as evidenced by a gradient
9.4.1 A complete thermographic inspection of a building from dark (cooler) at the bottom of the space to light (warmer)
may consist of an exterior or interior inspection of the complete at the top. As seen from the cool side of the construction: the
envelope, or both. Both types of inspection are recommended framing lines are dark, the areas between framing are light and
because each offers access to areas that may be difficult for the convection is still lighter at the top of vertical spaces.
other.
NOTE 3—Caution: Metal framing with no insulation may not fit this
9.4.2 Inspect all surfaces of interest from an angle as close
description. See Note 2.
to normal to the surface as possible, but at least at an angle that
permits distinguishing framing members. Make inspections 10.2.3 Insulation Partially Missing—The dominant effect is
from several angles, perpendicular, if possible, and at two as described in 10.2.1, except that missing insulation shows as
opposite oblique angles in order to detect the presence of a well-defined dark region, as seen from the warm side and as
reflected radiation. a light region as seen from the cool side.
9.4.3 Make scans from a position that allows a field of view 10.2.4 Other Thermal Patterns—Irregular variation of the
that encompasses at least two framing spacings wide and one thermal pattern in the spaces between framing members may
framing spacing high for an interior inspection and a floor-to- indicate a combination of possible causes, including varying
ceiling height wide and one-half that distance high for an density of insulation, convection or air leakage, moisture, or
exterior inspection. thermal bridges. A partial list of examples follows:
9.4.4 Effective corrective action requires a precise definition 10.2.4.1 Variable density insulation often allows air leakage
of the areas with apparent defects. Record each anomaly with and convection and thereby creates intruding areas of surface
annotation regarding the location of all recognizable building temperature variation.
characteristics such as windows, doors, and vents. The record 10.2.4.2 Areas where insulation contains significant mois-
may accommodate any requirement for calculations of enve- ture conduct heat much more readily than dry insulation or no
lope areas with anomalies. insulation. Within the moist region there may be a mottled and
diffused thermal pattern. Temperature variations within the
10. Thermographic Interpretation pattern are not extreme.
10.1 If apparent defects in insulation are not confirmed, 10.2.4.3 Thermal bridges may be caused by the presence of
corrected, and reinspected at the time of the thermographic fasteners or framing members.
survey, then thermograms or other precise identification of the 10.2.4.4 Air leakage, usually at joints and junctions in the
locations and types of apparent defects are required. The building envelope, typically produces irregular shapes with
interpretation of the thermogram allows determination of the uneven boundaries and large temperature variations. Air leak-
following information: age can be detected thermographically when air of a different
10.1.1 Locations of the regions where insulation is appar- temperature than the surface viewed comes from the side of the
ently missing or defective and their total area. envelope opposite the observer.
10.1.2 Locations of the regions where the insulation is 10.2.4.5 Indoor temperatures may vary from room to room.
apparently intact and their total area. This can result in large areas showing brighter than others, as
10.1.3 Location and total area of added insulation (if 10.1.1 seen during an exterior survey. Independent verification of
and 10.1.2 were performed in a thermographic inspection prior indoor temperatures can determine whether such variations are
to adding insulation). due to variations in indoor temperatures or to differences in the
10.1.4 Estimated total area of surfaces that cannot be thermal qualities of the envelope.
inspected. 10.2.4.6 If an object has been removed from a surface, there
10.2 Interpretation of thermographic images requires aware- may be a thermal signature where the object insulated the
ness of the following types of patterns: surface. This effect diminishes with time after removal of the
10.2.1 Intact Insulation—As seen from the warm side of the object.
construction: dark parallel lines, representing the framing; 10.3 If possible, the cause of the anomalous thermal image

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 C 1060
shall be determined. This may be done by calculations, 11.1.6.2 Markings on the building envelope, for example
ancillary measurements, experience, or by comparing the with tape, that delineate the apparently defective areas.
actual thermogram with reference thermograms for structures 11.1.7 Thermograms (if obtained) from the inspection with
with known anomalies. The report should substantiate such identifications of the region represented and with any interpre-
determinations. tations of the thermal images.
11.1.8 Identification of the examined parts of the building
11. Report
envelope and of those not examined.
NOTE 4—Much of the report may be recorded on a standard form 11.1.9 Results of any analysis dealing with the type and
devised by the user of this practice. extent of each apparent defect that may warrant remedial
11.1 The report on a thermographic survey shall contain, at action. This may be a simple reference to outlined areas on the
a minimum, the following information: thermograms.
11.1.1 Brief description of the essential construction fea- 11.1.10 Results of any supplementary measurements and
tures of the building. (This information can be based on investigations.
drawings or other construction documents when available). 11.1.11 Optional—Estimate of the total area and location
11.1.2 Note any unusual surface conditions, such as mois- where no insulation is apparent.
ture or reflective materials, and note the means used to account
11.1.12 Optional—Estimate of the total area and location
for these conditions.
where full insulation is apparent.
11.1.3 Geographic orientation of the building with respect
to the points of the compass, and a description of the 11.1.13 Names of members of inspection team and team
surrounding buildings, vegetation, landscape, and microcli- leader.
mate. This may be done with photographs of each side of the
building. 12. Precision and Bias
11.1.4 The equipment used, including model and serial 12.1 This practice is qualitative in nature. Therefore, the
number, and any critical settings used during the inspection. data determined is subject to interpretation. It requires the user
11.1.5 Date and hour of the inspection. to be able to distinguish framing members before proceeding.
NOTE 5—This practice does not rely on detailed weather information.
The appendixes detail the equipment specifications and
The ability to distinguish framing members is the critical criterion. weather conditions that are likely to meet the criterion of
Weather records from a nearby weather station should provide sufficient distinguishing framing members. Users can expect to obtain
data, when desired. anomalous thermal images from phenomena that are about the
11.1.6 Sketches/photographs of the building showing the size of a framing member or larger. Section 1.2 describes what
positions of the thermograms. If no thermograms were made, types of suspected problems the user can expect to detect.
then the following may be substituted:
11.1.6.1 Scale or dimensioned drawings that locate areas 13. Keywords
with apparently missing insulation, defective installations of 13.1 building envelope; infrared; in-situ; thermal insulation;
insulation, or other anomalies. wall systems; workmanship

APPENDIXES

(Nonmandatory Information)

X1. HOW TO DETERMINE SPATIAL AND THERMAL RESOLUTION OF AN INFRARED THERMAL IMAGING SYSTEM

X1.1 The user can determine in advance whether an adequate spatial resolution, the instrument must discriminate a
imaging system has an adequate IFOV and MRTD for the width, s, of one piece of framing from the distance, d, chosen
conditions of use. First the user must establish typical distances in X1.1.1. The same width, s, pertains to determining MRTD in
for indoor and outdoor inspections that are compatible with the 6.2.5. The instrument should have an IFOV defined by the
imaging system (see X1.1.1); secondly, an IFOV calculation following equation:
may be performed (see X1.1.2); then, MRTD experiments must IFOV # 500 s/d (X1.1)
be performed for those distances (see X1.1.3).
In the USA a typical value of s would be 0.0381 m (1.5 in.),
X1.1.1 Criterion Distances—The user may choose conve- when viewed from d 5 5 m (about 16 ft) would require an
nient distances to be probable maximums for indoor and IFOV of less than 3.8 milliradians.
outdoor scanning. Indoors the distance, di, might be 3 m (about X1.1.3 Minimum Resolvable Temperature Difference
10 ft). Outdoors, do, might be 5 m (about 16 ft). These (MRTD)—Depending on the construction subject to inspection
distances shall conform to the FOV (see section 6.2.3), IFOV and the thermal conditions, the instrument shall have an
(see X1.1.2), and MRTD (see X1.1.3) of the equipment chosen. MRTD, as defined by the following equation at the distance, d,
X1.1.2 Instantaneous Field of View (IFOV)—To ensure chosen in X1.1.1:

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 C 1060
| DR | * | DT | TABLE X1.2 Required MRTD for R-0.88 (R-5) to R-2.64 (R-15)
MRTD # h*R1*R2 (X1.2) Difference at 25 6 5°C Ambient Temperature
Required Minimum
Inside to Outside
where: Resolvable Temperature
Air Temperature
| 5 the absolute value symbol, Difference at 0.52 cycles/cm
Difference
R 5 thermal resistance, m2K/W (or ft2h°F/Btu), (1.3 cycles/in.)

h 5 the surface film coefficient, W/m2K (or Btu/°Fh ft2), °C °F °C °F

1 5 properly insulated area, 0.4 0.78 8 14
2 5 defectively insulated area, 0.6 1.1 12 22
DT 5 difference between inside and outside ambient tem- 0.8 1.4 16 29
1.0 1.8 20 36
peratures, K (or °F), and
DR 5 R1 − R2.
Tables X1.1-X1.3 list the MRTD required for the imaging TABLE X1.3 Required MRTD for R-1.76 (R-10) to R-2.64 (R-15)
system assuming that the imager is located inside the building Difference at 25 6 5°C Ambient Temperature
being tested and the building’s interior temperature is at 25 6 Required Minimum
Inside to Outside
5°C (77 6 9°F). The MRTD requirement for the imaging Resolvable Temperature
Air Temperature
system can also be estimated, using Eq X1.2. For exterior Difference at 0.52 cycles/cm
Difference
(1.3 cycles/in.)
surveys the film coefficient, h, changes with wind speed.
°C °F °C °F
X1.1.4 Test for MRTD—MRTD of the thermal imaging
system is defined by the following test conditions: 0.2 0.4 16 29
0.4 0.7 32 58
X1.1.4.1 Instrument Setting—The thermal imaging system 0.6 1.1 48 86
shall be set at the sensitivity that detects the smallest tempera- 0.8 1.4 64 115
ture variations. 1.0 1.8 80 144

X1.1.4.2 Criterion Distance—MRTD shall be determined

for indoors and outdoor applications at the distances di and do
chosen in X1.1.1.
X1.1.4.3 Test Target Pattern—The test target shall consist and a 7:1 aspect ratio. The dimension, s, is the same value as
of two plates with controlled, known temperatures, located at in X1.1.2, defined as the width of a single piece of framing.
the criterion distance, d, in front of the imaging system. The Other size patterns of the same aspect ratio may be used as long
near plate shall have a four-bar test pattern of w 5 (s/2)/cycle as w/d remains constant. See Fig. X1.1 for an illustration of the
MRTD experimental set-up.
TABLE X1.1 Required MRTD for R-0.352 (R-2) to R-1.76 (R-10) X1.1.4.4 MRTD Test Procedure—Someone slowly in-
Difference at 25 6 5°C Ambient Temperature creases the temperature difference between the two plates of
Required Minimum the target without communicating with the observer of the
Inside to Outside
Resolvable Temperature
Difference at 0.52 cycles/cm
Air Temperature display on the imaging system. The observer announces when
Difference
(1.3 cycles/in.) the test pattern comes into view. The difference in temperature
°C °F °C °F at this point is the MRTD for that test condition.
1.0 1.8 7 13 X1.1.4.5 Test Replicates—A minimum of three separate
1.2 2.0 8 14
1.4 2.5 9 16
observers shall perform the procedure in 6.2.6.4 to establish an
1.6 3.2 11 20 average value for MRTD.

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NOTE 1—A test pattern, consisting of four rectangular slots, permits a comparison of the temperature of the near plate of the test target with the far
plate. The plates are initially at the same temperature. Someone increases the temperature difference between plates until an observer announces when
the test pattern comes into view on the display. The difference in temperature at this point is the MRTD for that test condition.
FIG. X1.1 Test for Minimum Resolvable Temperature Difference (MRTD) of Infrared Imaging System

X2. PREFERRED CONDITIONS FOR PERFORMING INFRARED INSPECTIONS OF FRAME CONSTRUCTION

X2.1 Infrared inspection requires a sufficient difference in inspection for light frame construction and approximately 8 h
temperature from inside to outside (DT) for a sufficiently long for masonry veneer construction. DTs greater than 10°C reduce
period of time, as described in this section, to produce these times. Direct sunlight and other strong sources of thermal
discernible differences between areas with studs and areas that radiation make discrimination of uninsulated areas unreliable.
may contain insulation. The preferred measurement of DT is Exterior surveys should be performed after sunset and before
surface to surface, because this minimizes problems with sunrise for best results.
accounting for solar and wind effects. Air-to-air measurements X2.3.2 Avoid Wind—For exterior surveys, the wind speed
are also permitted under this practice. The following environ- should be less than 6.7 m/s (15 mph) and the building surface
mental conditions are suggested for thermographic inspections: should be dry.
X2.2 Minimum DT—Minimum temperature difference
(DT) of 10°C (18°F) between interior and exterior surface or X2.4 Other Conditions—Although it is recommended that
ambient air temperatures for a period of 4 h prior to test. the conditions in X2.3-X2.3.2 prevail at the time of inspection,
it is recognized that the thermographic inspections can be
X2.3 Using Ambient Air Temperature Measurements— performed under other conditions if sufficient knowledge is
Ambient air temperature measurements cannot account for the used in taking and interpreting the thermograms. For example,
strong radiative effects of the sun or for convective effects from a wall exposed to direct solar radiation will experience a
wind, so the following precautions should be taken when using temperature reversal; the studs and voids will appear warm and
air temperature measurements for DT: the insulated section cold on interior inspections. Interior
X2.3.1 Avoid Solar Radiation—No direct solar radiation on surveys may be possible on veneer surfaces or ceilings under
the inspected surfaces for approximately 3 h previous to the attics an hour or two after sunrise.

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