infrared thermal imaging

by Joe DeMonte

As the saying goes, "garbage in, garbage out." This truism is every bit as applicable in thermography as it is in computer data-mining. The difference is that the inaccurate data which leads a thermographer to a false-negative conclusion could result in a multi-million dollar catastrophic failure of a company's electrical distribution system.

FORWARD

Infrared thermography has become a very popular means of testing electrical and mechanical systems over the past fifteen years. As it relates to predictive/preventive maintenance (P/PM), infrared thermographers look at the thermal energy that is emitted from an object or group of objects, explain what is normal, see abnormalities and report them. In turn, someone can act to fix whatever is wrong as long as they get the information in a usable, graphic and easy-to-understand fashion. This method works well on heat emissions from most objects, including building roofs. A well-prepared, graphic and accurate map of the infrared signatures of a roof can be of significant benefit to the roof consultant at all stages of that roof's service life. This type of testing is commonly referred to as an infrared roof moisture survey. Infrared thermography is not leak management, it is predictive maintenance. No matter how the water got into the substrate, the purpose of this type of survey is simply to find and document where the water is. Performing infrared roof moisture surveys while standing on the roof is not the best method because imagery from a walk-on survey is not as useful as aerial imagery.

ABSTRACT

Infrared thermographers literally walk by more work than they can do. The world is one big radiator, and new, non-traditional applications for infrared thermography are being found every day.

This paper discusses one of these non-traditional applications; specifically, the use of infrared thermography to find whether or not concrete reinforcing (grouting) has been properly placed in Concrete Masonry Unit (CMU) or 'block' walls. These walls are being erected everywhere. They are used to build discount stores and shopping centers, schools and buildings of every size and shape. They are almost never built exactly to specifications, and by using infrared thermography it is possible to see and report the faults in the walls, so that timely repairs can be accomplished.

This paper discusses the development of the technique that we use to image and evaluate these building walls successfully, and to make usable reports of our findings. I also discuss some market factors for infrared on buildings in general.

Introduction To Infrared Thermography

Think of the world as a radiator...infrared thermographers do. Thermal energy travels at the speed of light in all directions. An infrared (IR) camera detects this [heat] energy and converts it into pictures or thermographs of heat. One can learn a lot about the world by looking through the lens of an infrared camera.

Think back to the 1990s. How important was building energy efficiency, building moisture or building quality? Now think about the past 6 months....has your boss asked you to study your energy usage? Thinking "green" has become in vogue. Why is that? Is it because your boss recently downloaded "An Inconvenient Truth" and Al Gore convinced him or her that global warming is real and something must be done about it? No "green" thinking is about "green-backs". Building costs and energy costs are on the rise and by inspecting a building with IR and other techniques, the owner can determine what needs to be done to manage the building asset better, use less energy and save money.