Thermography

I’ve noticed that some of our competitors are using infrared cameras. I’m interested in buying one but I am not sure that there is a real advantage in having to spend so much money on something that I can accomplish with a moisture meter.

Infrared cameras are sometimes called IR or thermal imaging cameras. To begin, you may not have noticed that Infrared camera prices have dropped considerably within the last few months. Infrared cameras are sometimes called IR or thermal imaging cameras. This puts the thermal imaging technology within the financial reach of many more companies. Those who have already purchased a thermal imaging camera are probably hoping their competitors never get one. But you can't stop progress and eventually most everyone in the cleaning and restoration business will be using this technology as frequently as we use moisture meters. So, let's go over a few things that might help you decide what's best for you. Then we'll talk about camera features.

The Technology
Let's clarify what this technology does and review a few points about the physics of infrared. Infrared radiation is an energy wave that is a little longer than the visible light wave. On the electromagnetic spectrum infrared has a lower frequency than the red part of the visible light, thus the designation infra (below) red. Hollywood has departed from the science of this technology and portrayed it as something that can see through walls and clothing. Thankfully, IR cameras do not see through walls or clothing. If we could see through walls the technology would probably be useless as a building diagnostic tool since we would not know whether we are looking at the interior wall, exterior wall, or the building next door.

For the purposes of this discussion, we are talking about radiation in a band width with wave lengths between 7 to 15 microns. So, what does the camera "see"? A good guide to remember is that the IR camera "sees" the same surface that your eye sees. It is detecting, with few exceptions, only infrared radiation coming off of and from the specific surface that your eye is observing. All surfaces that we look at emit and reflect infrared radiation. In some cases infrared radiation transmits through a surface. An example would be thin plastic (e.g., 1 to 10 mil), regardless of the color. Infrared radiation does not transmit through glass in the 7-15 micron band width. This means that an IR camera cannot pick up radiation from objects on the other side of glass. Learning to use an IR camera is not hard. It is different and therefore requires training in the physics of infrared, principles of thermodynamics, and the use of the camera.

This technology does not detect moisture, missing insulation, or air leaks. Good thermal imaging cameras are incredibly sensitive to thermal differences. There is a thermal difference where evaporative cooling is taking place and in certain cases when there is missing insulation or air leakage. These conditions can result in expensive problems for the building owner. Many of you are in the business of solving commercial and residential building problems. The faster and more accurately you can solve and document these problems, the more successful you are. That is why an IR camera has turned out to be a highly successful tool for those in the water damage restoration industry.

Solving the Moisture Problem
The principle that allows us to locate moisture on the interior walls is evaporative cooling. Evaporative cooling can be very slight. There may only be a 1ºF temperature difference from wet to dry. A good IR camera will easily show that slight temperature difference.

Let's say a customer calls and is in a panic. They just arrived home from being gone a couple of days. A pipe froze and due to a subsequential leak, there is standing water in the family room at a depth of about 1 inch. Step one is easy: extraction. We cannot solve the remaining problems until we identify what is wet. The process of finding all areas that have moisture issues can be a long and tedious task when using only a moisture meter. The thermal imaging camera quickly and accurately shows all relevant thermal differences. The investigation results in the preliminary determination of the problem. It might be moisture; it might be missing or compromised insulation on a cold day; it might be air leakage on a cold day. All three of these issues can look the same on the thermal imaging camera when investigating the interior of the building on a cold day. So, the IR camera needs to be used in conjunction with the moisture meter to quickly and accurately verify the presence or absence of moisture.

Once the moisture has been located and verified, the process of drying can begin or be modified. As drying proceeds, there is a need to monitor the drying process. There's no better tool to monitor the drying than an IR camera. The areas that are drying and those that are not are easily located; the air movers can then be readjusted; and the drying process continues more efficiently.

Customer confidence is valuable and critical to growing a business. The IR camera also allows you to better document the drying process by taking IR images that can be used in your report. And, as the old saying goes, "seeing is believing." When the customer observes you using the IR camera their confidence level goes up immediately. The kind of documentation that is generated with IR technology is also a good risk management tool. We have seen numerous cases where restorers are accused of having failed to adequately dry a structure or its contents.

With "before" and "after" IR images, showing the progress of the drying project, you can better document that at the time that you left the project, the structure and the contents were dry. Those images can save you a lot of stress, not to mention a lot of money.

Available IR camera features

Although there are many differences in features from one camera to another, some of the major items to look for are:

Noise Equivalent Temperature Differential (NETD) is another way of saying temperature sensitivity. The lower the NETD number, the better (e.g., 0.07º C is more sensitive than 1.0º C; 1.0º C is more sensitive than 1.5º C). This is important because evaporative cooling results in a small temperature differential, especially toward the end of the drying process. The faster the moisture evaporates, the larger the temperature differential (about 4ºF or 5ºF). As the evaporation slows down the temperature differential becomes smaller (about 1ºF or 2ºF) and you’ll need a very sensitive camera to monitor it. The higher the NETD, the grainier your image will appear and can result in missing some very slight thermal differences.

Detector size: Most cameras are either a 160x120 or a 320x240 array. It is my recommendation that the 160x120 is more than sufficient for moisture detection. It will serve adequately and is less expensive than the 320x240 array.

IR plus visible light: The latest technology is IR Fusion. This technology incorporates both a visible light camera and the infrared camera so that you can see both images. Why is that helpful? Infrared, being a thermal image, can be challenging for the thermographer and customer when trying to identify exactly where the issue is. Much of that confusion has been eliminated with IR Fusion. It also eliminates the challenge of standing in the same spot and trying to take another picture with a digital or visible light camera.

Voice memo recorder: Not all cameras have this feature but it is very practical from the standpoint of documentation and speed.

Radiometric: Most all cameras now provide you with a temperature reading on the camera. Some have a center point temperature; some have hot and cold readings on the camera; and some show the temperature where ever your cursor is positioned. It's important to have at least a center point temperature reading.

Software: Take time to learn about the software that comes with the camera. It’s best to get a full post analysis software program that enables you to work with the palettes, the level, the span bar, comments, annotations, and reports. Some cameras come with very basic software and you must pay extra for full post analysis software. Be sure to find out exactly what you are getting.

Training: Another expense to take into consideration is training. You can read the user manual but that won’t prevent you from making costly mistakes. I strongly urge you to take a training course in the physics of infrared and the principles of thermodynamics so that you can use the camera responsibly and not get into trouble. If you are in the restoration or remediation business, then you don’t need a course in industrial and electrical applications. You need a course in moisture investigations and building envelope investigations.

Screen size: Although we tend to get excited about how small a computer or a phone is; the thermographer's job is harder as the screen size decreases.

Warranty and service: Check out the warranty. Some cameras have a one year warranty. Some have a two year warranty. Where is the camera manufactured? How fast and how easy will it be serviced if needed?

Other features: The above are just a few of the most important considerations. There are many other features to consider: number of palettes; level and span adjustments, battery time, method of saving images, weight, and drop test ratings, etc.

In summary, to be competitive the professional water damage restoration company will need to consider seriously the addition of the IR technology. It might be that the most expensive thing you can do is to decide not to use IR.

— Jim Holland