Infrared thermography is a noninvasive tool for inspecting roofs, troubleshooting leaks and enabling maintenance. IR roof inspections traditionally have been left to professionals, but they charge as much as $1,000 per day, plus expenses.
Granted, trained inspectors might provide CAD drawings of problem areas, videotaped infrared scans, segmented structural analysis, corrective action recommendations, repair estimates, year-over-year comparisons, Web-based reporting and other advanced services. However, if routine inspections are cost-prohibitive, funding may be elusive. With thermography technology becoming increasingly affordable, plants on a tight budget can consider a do-it-yourself approach.
Thermal inspections: The insulation surrounding a roof leak is wet. Infrared cameras can locate this moisture quickly, including its point of entry and scope of the damage or deterioration, even if it can’t be seen by the naked eye.
Thermal imaging can be used on the inside of a building to detect damaged insulation and moisture intrusion. In a typical application, the camera is used to find cool spots, which can then be probed with a moisture detector to determine whether the areas are moist and cold because of a leak, or dry and cold due to an insulation or other defect. But be careful — today’s cameras are sensitive enough to “see” the heat of a colony of termites inside the wall, and you may find problems you weren’t looking for.
You can also use thermal imaging to isolate leak locations where the underside of the roof is inaccessible. During a dry spell, train the camera on the ceiling or other area where water ingress has occurred, then apply water to suspect roof areas. When you flood the area where the roof is leaking, the thermal image will clearly show the cooling effect of water in the ceiling long before it can be observed with the naked eye. Be sure to flood each area long enough to be sure water is or isn’t leaking before moving onto the next — 30 minutes is a typical test time.
Routine, semi-annual roof inspections and maintenance reduce long-term energy and repair costs, extend roof life and help prevent mold growth and sick building syndrome. IR imaging promotes quicker, easier, more accurate diagnosis and spot repairs instead of expensive tear-offs. Thermal inspections also can locate energy inefficiencies and electrical or plumbing problems within a structure.
Desirable features: According to David Francoeur, director of marketing at FLIR Systems, “IR camera buyers want the ability to provide definitive proof through pictures of roof leaks, structural problem, water damage or standing moisture, but they want the process to be as simple as possible.”
To simplify diagnoses, some infrared camera models include dew point alarms that provide visible and audible alerts to the presence of moisture. Laser locators that point to damaged roof areas make it easy for fellow inspectors to mark with spray paint the perimeter of the damage. Safety from falls, a chief concern of roof inspectors, is improved with heads-up displays in which the infrared image is projected in front of the eyes in safety goggles.
Camera shopping: Feature-rich infrared camera systems cost at least $10,000, but less sophisticated, more affordable alternatives might be perfectly suitable. Further savings can be found in used and demo cameras, short-term rentals and longer-term leases.
Low-cost alternatives may lack certain bells and whistles, but a test drive can determine whether the camera is adequate for your purposes. To be safe, consider a vendor that offers lease-purchase programs or provides trade-in credit for upgrades to a higher model.
Inspection standards: Two applicable standards include ASTM specification C-1152, “Standard Practice for Location of Wet Insulation in Roofing Systems Using Infrared Imaging” and ISO 6781, “Thermal Insulation, qualitative detection of thermal irregularities in building envelopes, Infrared Method.”
Contact Contributing Editor Sheila Kennedy, managing director of Additive Communications, at [email protected].
