Understanding Infrared Thermography Reading 3

■ Building Insulation and Other Factors
As previously discussed, the conductive heat flow through a laminar structure
is related to both the temperature difference from one side of the structure to
the other and the aggregate thermal resistance of the materials encountered.
The higher the thermal resistance (insulating properties), the less heat will
flow; therefore, when steady state heat flow can be established, mappingthe
temperature on the outside of a structure and knowing the thickness and the
inside temperature, permits the determination of the insulation properties.
The measurement of conductive heat flow for insulation assessment is only
one factor; however, in practical heat loss determination, other factors such
as air infiltration and exfiltration, chimney effects. and thermal short circuits or
bypasses can be serious enough to completely negate the benefits of good
insulation. Thermographers have learned to consider the total structure when
evaluating the results of thermographic surveys and to recognize and isolate
thermal patterns typically associated with air flow as well as those caused by
insulation deficiencies.
Charlie Chong/ Fion Zhang