It's Not Enough To Have Good Tools

Lookie, Ma! I Can Measure Water Temperature with this Thing-a-ma-jig!

I’ve seen this a couple of times now in inspector’s reports. They are using a digital laser thermometer - technically, an infrared laser pyrometer - to measure water temperature. It’s a great little tool and helpful in a bunch of applications. One teenie little problem.

It doesn’t work to measure water temperature. Not even close.

Oh, they will get a number, but it won’t be an accurate one. The reason is that they, the inspector, have a tool that they do not understand. Spot pyrometers have been used, successfully, for years in asphalt paving, HVAC, and other industries.

Home inspectors adopted them as a fast, easy way to check temperatures on ducts and such. For that, where a qualitative number is needed, they work great. We don’t care what that number is, just that we have a heat profile being generated.

Measuring water temperature is a quantitative measurement. We care very much what that number is and it needs to be accurate. The reason is pretty simply. A ten degree difference in water temperature can take scald times from 30 seconds to less than five. For a small child or an elderly individual, hot water temperatures are important. Both of these populations have slower reflexes and mobility to react to scalding water and yes, people get badly scalded every day.

That’s where not understanding your tools comes in if you are a professional home inspector. In this case, some training on the physics behind the tool. The digital laser thermometer, as they think of it, is actually an infrared device. Infrared cameras and measurement devices follow the same principles. They are not measuring the actual temperature but rather the emissivity of the object. All objects do one of three things with energy: they can reflect it as glass and metal does; it can transmit it as translucent materials (like water) does; or, they can emit it as heat radiation as most solid, non-reflecting surfaces do.

Water has lousy emissivity but high transmission so the number that the inspector sees isn’t even within shouting distance of accurate. Yet, because they do not understand the deficiency in their tool -actually, the deficiency in their knowledge and skills as the tool will do what it is designed to do - they proudly put pictures into their reports documenting a false reading.

Which won’t matter much. Not until someone gets badly scalded.

Then, it’s a real problem and the home inspector bears some significant responsibility.

Good Tools Don't Count If You Don't Understand Them from Paul Duffau on Vimeo.