Infrared Thermography (IR Scan) is the science of using electronic optical devices to detect and measure thermal radiation and correlating that to temperature variations. When insulation gets wet it loses its thermal resistance. Wet insulation absorbs and hold heat more readily during the daytime than dry insulation, which means that an IR Scan is more effective when completed at night as there is more heat retained in the wet insulation than the dry insulation allowing the IR optical device to detect the subsurface temperature differences and by capturing the as Thermogram images.
Thermal infrared (IR) imaging is not a new science however, by combining UAV (drone) technology and the high-resolution multi-spectrum camera, normally invisible variations in temperature can be seen clearly by the user allowing for more accurate locations of subsurface thermal anomalies. The combination provides greater confidence in the results and takes non-destructive testing (NDT) of a building envelope to a whole new level by pinpointing the exact locations of energy loss and water intrusion. This translates to early detection of problem areas so that proactive repairs can be initiated before a small problem becomes an unanticipated and unbudgeted capital expense. For instance, the repair of a roof leak located by IR can avoid costly long-term damage to the roof deck and structural elements. The Infrared Roof Plan outlines the locations of the anomalies identified with the aerial infrared scan.
FORSMITH Building Science Consultants (FORSMITH) was commissioned to complete Infrared Scans for multiple large warehouse facilities totally approximately 7.5 million sq. ft. in the Woodbridge, ON area. the issue the client is facing is that all of the roof assemblies are in varying degrees of failure and need to be replaced however the estimated cost to replace all the required roof assemblies is close to $100 million and has not been allocated for this magnitude of capital expenditures, not to mention finding a roofing contractor that is capable of undertaking this magnitude of re-roofing on short notice.
The client was extremely skeptical about the accuracy of the combined technologies, so FORSMITH undertook to complete an IR Scan on one of the warehouse facilities with a roof area of 250,000 ft2 by using our Unmanned Aerial Vehicle (UAV) system along with a handheld radiometric infrared camera to gather the IR images and cross checking the accuracy of the Aerial scan with a handheld IR scan and verifying yet again with cut tests of the roof assembly to prove the accuracy of the Thermograms. This verification procedure convinced the client that the UAV IR Scan was actually more accurate than the handheld IR scan and they requested that we complete the remaining 7.25M ft2 of IR scan using our UAV, which allowed us to complete an unprecedented amount of IR scan within a very short allocated time frame.
The IR scan results of each roof were analyzed and overlaid onto a roof plan with the thermal anomalies identified and dimensioned onto each roof plan as shown below. This allowed us to accurately quantify the percentage of roof area that was wet and visually see where it made the most sense to replace roof areas and where it made good sense to provide surgical repairs to selected roof areas in order to obtain the best bang for their buck. As indicated below roof quadrant 1 has no wet areas and can be deferred for replacement until a later date. Whereas roof quadrant 2 has a substantial percentage of wet area and should be replaced immediately. Roof quadrants 3 and 4 have some wet areas that can be surgically repaired as an interim measure to prolong the lifespan and defer the capital expenditure for another year.