Retrotec USACE - Manual (Page 334)

G4 ENERGY & PROCESS ASSESSMENT PROTOCOL
the building’s performance as well as aiding in the detection and location of build-
ing defects. Its ability to detect thermal anomalies within buildings allows it to
detect missing insulation, locate internal building components, show water intru-
sion, and discover pipe leaks and electrical problems, among many other things.
IR thermography, in conjunction with other tools such as a water-spray
system (spray rack), allows investigators to determine nondestructively whether
water intrusion is occurring within most building components, including win-
dows, doors, roofs, walls, and fl oors. Additionally, air provides a conduit into
the building for moisture as well as cooling or warming the internal environ-
ment. A pressure test system (blower door) with the use of IR thermography
allows the operator to locate the incoming air, fi nding its source of intrusion
and clearly documenting its location.
The fact that building components have different heat capacities and ther-
mal conductance allows discovery of hidden internal building components,
including studs, pipes, and insulation (missing or present). IR thermography
detects the differing thermal patterns, allowing for easy discovery and location
of building components or defects.
Thermography is the only method that provides real-time temperature
monitoring, quickly scanning large areas and providing visual documentation in
reporting those fi ndings. Thermography can be combined with other methods,
or other techniques can be used in parallel, such as continuous short period
surface and indoor air temperature measurements with data loggers, pressure
drop measurements, air fl ow measurements, smoke tests, tracer gas tests, and
heat fl ux measurements, among others.
For many testing procedures, a baseline IR thermography scan is per-
formed fi rst, evaluating the building in “normal” conditions, followed by IR
thermography during the test. For an air barrier test, a pressure drop or in-
crease can be provided by a blower door system or the building ventilation or
HVAC system. If the outdoor temperature is cooler or warmer than the indoor
temperature, the air movement created by the pressure difference will cause
the temperature of the building envelope with which it comes in contact to
change, creating thermal patterning that the IR camera can detect. The invest-
ment in acquiring an IR camera is still relatively high. However, the prices are
decreasing and the price/performance ratio is constantly being improved. On
the one hand, a great amount of available IR equipment gives a chance for its
wider use; on the other hand, the abundance of IR cameras in use enhances
the competition between the consulting fi rms. The selection of a particular
device depends on the purpose of use; it is recommended that it have radio-
metric features that allow the processing of the images afterwards.
As indicated by many camera manufacturers, the IR camera seems to be
a technically easy tool to operate; the problem is in interpreting the thermal
images, not producing them. In many cases, data misinterpretation has caused
thermography to be considered a discouraging technique, and in some cases
“voodoo science” because of a thermographer’s ability to postaadjust (tune) the
images. Tuning of the image can enhance or detract thermal patterning, some-
times drastically changing the interpretation of the image. However, it is true