Detecting a plumbing leak
Here at Fluke we pride ourselves on the versatility of our tools, but sometimes that versatility surprises even us. Not long ago Jeff Gust, Chief Metrologist at Fluke, ran into just such a story from a fellow metrology professional at a Measurement Science Conference.
It seems that Scott Mimbs - the now-retired NASA Metrology Program Manager - a few years prior had encountered a plumbing challenge in his Florida home. In the community where he lives, most houses are built on thick concrete slabs. In this type of construction, water pipes are buried in the dirt, 4 to 6 inches (10 to 15 centimeters) beneath the concrete. Until recently the pipes for potable water were usually copper, which - as it turns out - are very susceptible to leaks from corrosion and vibrations induced by the water flow.
One day Mimbs and his wife noticed that when they turned off the faucets for the shower and sinks, they could still hear water running. Mimbs first tried to track down the problem using a mechanic's stethoscope. That amplified the sound of the leak, but didn't help locate it. He had a hunch the leak might be in the hot water pipe, so he shut the hot water valve off and the sound went away. When he turned it back on the sound came back, proving his hunch.
The latest in the 60 series of non-contact IR temperature test tools are the 62 MAX (shown) and the 62 MAX+ Infrared Thermometers.
Following the heat
Narrowing it down to the hot water system helped but still didn't pinpoint the exact location of the leak, so Mimbs called a local leak-detection company. After getting an estimate of over $400 just to find the leak, Mimbs decided to see what he could do to find it on his own. One point in his favor was the fact that he was looking for hot water. "Because the leak was in the hot water system, I was pretty sure I could find it with an infrared (IR) thermometer," says Mimbs.
He researched likely IR thermometers on the internet and found that the Fluke 62 Mini Infrared Thermometer was both affordable and had a high number of positive reviews. He even found one on sale, but because he needed it immediately he wound up purchasing it locally and paying full MSRP. Even at that it was a fraction of the cost of hiring the leak-detection company.
When Mimbs returned home he enlisted the help of his wife, who was curious to see how he was going to use an IR thermometer to find a water leak. To demonstrate, he first pointed the thermometer at the floor beneath their feet in the kitchen, and then pointed it at an area several feet away in the family room. Talk about luck - the second reading was 10 degrees F (-12 degrees C) higher than the first.
To isolate the leak more precisely, he and his wife plotted out the temperature gradient on the floor using sewing chalk. Carefully measuring every few inches, they drew the first chalk line where the temperature changed by more than 2 or 3 degrees F (-16.6 or -16.1 degrees C) , and then drew subsequent lines as the temperature increased. Ultimately the temperature gradient revealed about a 20 degrees F (-6.6 degrees C) difference from the regular floor temperature to the hottest point.
In the end, the entire gradient turned out to fall within about one 18-inch-square (45.7-centimeter-square) tile. So Mimbs took up that tile and hammer-drilled several holes in a 5-inch to 6-inch (12.7-centimeter to 15.2-centimeter) circle, allowing him to break a hole through the concrete at the hottest point. When he reached the dirt he knew he'd picked the right place because it was wet. Mimbs applied a temporary repair on the pipe, so they could use the hot water that night, and called the plumber.
A true multi-purpose tool
The next day the plumber was very impressed by Mimbs' ingenuity in detecting the leak so precisely, and thereby limiting damage to the floor. The same plumber was even more impressed when four months later he returned to repair another hot water leak that was located using the same technique. On his second visit, the plumber jotted down the make and model of the IR thermometer so he could add it to his toolbox.
Shortly after that, Mimbs lost the Fluke 62 to his wife, who put it to work in the kitchen for testing oven temperatures and aiding in the temperature-sensitive process of making homemade yogurt. All's well that ends well, though, because she has since received a Fluke Food Pro Plus Infrared Food Thermometer and the Fluke 62 has returned to Mimbs' tool bag.