Magic Vision

• By Julie Sturgeon
• 07/01/07

Finding leaks in a building envelope used to be easy: Wait for a musty odor, tear open the walls, and find the problem. Of course, it was also expensive, not to mention disruptive.

Today, thanks to military technology declassified four years ago, construction experts can see right through those walls and insulation to diagnose trouble before it reaches epic proportions. The trade-off: Such super vision requires sophisticated operators.“I had to register my equipment in order to take it out of the country because it’s the kind of thing a terrorist would love to have,” said Ron Isaacson, owner of Space-Man Consulting in Chicago.

Infrared Imaging

He’s talking, of course, about thermal infrared imaging cameras — technology so sensitive to temperatures, it can measure as little as a tenth of a degree variation. A wall or ceiling deficient in insulation doesn’t stand a chance of hiding that from curious eyes, said Jeff Bishop, technical advisor for the Institute of Inspection, Cleaning and Restoration Certification in Vancouver, WA. The same holds true for water leakage — simply flood the pipes with hot water for a few hours and then take an infrared scan at either dusk or dawn, before the solar load becomes a factor.

“It takes a lot of forensic investigation because where you see or feel the problem is not necessarily where it originates from,” Isaacson said. That’s why thermal infrared imaging cameras are particularly good at locating leaks that occur in the roof plating, and they’re adept at sniffing out electrical faults as well as checking insulation around boilers and heating equipment.

On the other hand, the cameras are not cheap. According to Bishop, the less sensitive models start at $6,000; Isaacson’s arsenal contains some priced in the $20,000 range. That alone puts a crimp in many universities’ maintenance budgets. But it’s the training required to accurately interpret the results that often proves to be the real reason facilities supervisors hire third parties to handle the inspections. The feedback is riddled with false positives — plumbing lines, for instance, show up as a water leak. Wiring can also throw the image for a loop, as can solar heat. And always keep in mind that this tool isn’t a modern-day dousing rod — you can take a photo of a puddle of water standing on the roof and the camera won’t show that as long as it’s the same temperature as the roof it sits on.“It doesn’t find water or mold. It finds the anomalies,” Isaacson explained. “Reading a thermal scan is as difficult as properly interpreting an X-ray.”

So it’s no surprise operators log in 60 hours of classroom work just to reach a level-one thermographer designation. Experts say universities that decide to own the equipment need someone who is at least at level two — which gets into the diagnostics of mechanical equipment rather than just building materials and general maintenance — to get a good return on investment for the cameras. And insiders agree the field is still in its infancy.

Ultrasound and Other Options

Some technicians also use ultrasound waves to search for hidden answers in walls — typically when they can’t set up the scenario to force a temperature differential, or if the suspected problem lies deeper than infrared can penetrate. But there are also other, more affordable tools on the market that universities can rely on for educated guesses before calling in the thermal camera experts.

Moisture Meter. Move this $300 gadget across the surface of a wall and its pads emit electrical impulses. Where there is water, it creates a circuit that activates a meter reading on the moisture percentage in the area. Most materials in buildings will read between 8 and 16 percent, according to Bishop. When readings jump above 16 percent, the wall is ripe to support mold, too.

False positives are still possible, however. For instance, if you scan a wall that contains steel studs, the needle pegs over each stud. “After you’ve practiced a bit, you can usually tell the difference between this and moisture because they are very linear and occur every 16 to 24 inches,” Bishop assured. On the other hand, if you have wet insulation that is not touching drywall, you may not get an indication that the thermal imaging camera would definitely detect. Nor can you find water deeper than ¾-in. in most cases. And because concrete contains a variety of conductive materials, a moisture meter isn’t highly useful in that situation. Drywall and wood are its forté.

Digital Thermometer. For $60 to $110, you can invest in a digital thermometer that simply shoots a laser dot on the wall. The beam bounces back to a thermometer that displays the temperature. If the vast majority of the wall reads 70°F with a spot or two registering at 80 or 85°F, bet money that you’re missing insulation. Wet spots read cooler than the wall.

The devices are quick and easy to use; some maintenance departments also use them to check engine temperatures on motorized equipment to make sure the motor isn’t overheating.

Borescope. Need to see it for yourself? Then cut a 6-in.-diameter hole in the wall, insert a borescope into the space to let its lens take a peek around, and send the image directly to your eye. Flexible versions can bend to see into most of the cracks and crevices. It’s exactly what Bishop does whenever he encounters water stains on the wall, yet can’t pinpoint a high moisture content using other means. Plan to spend in the neighborhood of $5,000 for a borescope.

No matter which combination you choose, the key is to set up a regular inspection schedule, said Isaacson. After all, each of these tools finds the out-of-place, so facilities managers need to know what is normal. And don’t assume you’ll completely sidestep tearing out a wall. “These tools narrow down the possibilities,” he added. “You save time and money because you don’t have to rip open the entire surface to see what’s going on — just select portions.”