Thermal Imaging Applications
Electrical Applications for Thermal Imaging
Thermal imaging is an extremely cost effective and sometimes the only way to inspect energized electrical systems. Thermal Imaging can be utilized to inspect high and low voltage systems, distribution lines and control components and potentially almost any element of an electrical system that can be safely viewed while under load.
The main objective when performing electrical inspections is to locate components with abnormally high temperatures.
The root cause of excessive heat in an electrical component will be due to excessive resistance. This is usually caused by the current being forced to flow through a loose or corroded connection or when the load on the component approaches or exceeds the component's specification. Both instances are symptomatic of a problem which if left uncorrected can over time lead to the failure of the component.
Electrical equipment by their very nature emit heat, when inspecting electrical systems the infrared camera allows the thermographer to visualize and calculate an electrical component's temperature however temperature alone will not be an indication of a fault. A good thermographer will need to draw on his training and experience to take into account factors such as load, ambient temperature, component characteristics, infrared reflections and wind to name a few in the diagnosis of a system.
Building Envelope/Commissioning Applications
By using modern technology we can all get a better understanding on how each part of the buildings structure, building materials and layout can affect the performance of the building. We can put all the standards out there and make all the calculations work on paper, but if the building is not performing as designed how can we achieve the goals and standards that are set out before us.
With careful planning and cooperation we can manipulate the buildings mechanical systems to either put the structure into a positive or negative pressure to stress the buildings thermal envelope. With the use of infrared technology we can pin point out any anomalies within the building. Along with that comes air infiltration or exfiltration depending on how the building needs to work. Not only can we see the defects that deal with the air infiltration we can also pick up latent moisture that may be present.
A new facility or a sizeable renovation are good candidates for infrared inspection. Image below is from a new school commissioning job. The construction fence is still up and several new windows are already bad. The red halos are indicating the argon gas in between the double pane windows has escaped. Many other deficiencies can be found using infrared, windows are only one example.
Mechanical Applications
Any system where heat or cold is an indication of a problem can benefit from an inspection by a trained thermographer using the appropriate equipment. Mechanical systems which inherently generate heat due to frication of moving parts are an obvious candidate for this NDT technique, for example this bearing on a large ball mill.
Non moving mechanical "structures" like refractory systems and insulation materials can also be inspected using thermal imaging techniques. Excess cold can also be an indicator of a problem. Thermal imaging is very useful in detecting ice buildup in gas liquefaction systems and cold rooms as indicated by the dark spots in this image of an "ice box".
In summary if you think that heat or cold would be an indicator of a problem with a mechanical system your understanding of that system's mechanical and thermal characteristics can probably be greatly enhanced by taking at look at it using a thermal imaging system.
Flat Roofs Applications
Infrared inspections of flat roofs are a proven method of finding roof leaks/entrapped moisture. This inspection is very weather dependant. Flat roof inspections are performed at night after the sun goes down. For a successful inspection you need a day of full sun, little to no wind conditions, and no standing water or snow on the roof. Not all roofs are good candidates for infrared; two examples would be roofs that are heavily ballasted and white PVC roofs (highly reflective).
How flat roof thermal imaging works:
The roof absorbs the suns energy during the day. When the sun goes down the roof begins to cool releasing its heat into the atmosphere. Areas with wet insulation cool at a slower rate than areas with dry insulation therefore making them visible with infrared. Typically areas of suspect moisture are outlined & numbered with spray paint for future reference. Many building owners follow up with core testing of the areas in question to verify moisture is present.
As seen in the image above, at least a third of this roof is holding moisture. This image shows the right side of the roof needs extensive repairs and or replacement.
Process / R & D
Infrared applications for Process and R & D can be endless. Whether you want to inspect injection molding parts , cookie temperatures coming out of an oven infrared can be a very helpful diagnostic tool.
Consider this example of an oven. This customer wanted to add an additional high temperature cutoff to this new oven. It was critical to place the thermocouple where the highest temperatures are seen inside the oven. Several tests were done to locate the area of interest. The oven was brought up to temperature:
- Test one: High emissivity targets were placed throughout the inside the oven.
- Test two: High emissivity targets were placed on the inside walls of the oven.
- Test three: Oven was imaged with nothing inside.
Image above shows image using the isotherm feature (Test 3). Black areas indicate the highest temperatures which are greater than 620F. This method gave us the best result, so we could recommend installing the thermocouple in the upper right side of the oven with confidence.
Data Centers
Data Centers require nearly 100% uptime. In many instances any interruption in power can cost millions of dollars. Imagine a large retail chain or a bank if they could not scan a product at the register or make a credit/debit card transaction. Data centers are full of critical equipment from distribution, to PDUs (power distribution units), UPS systems, backup generators, batteries, and air conditioning.
Below is an example of a PDU with a breaker problem where it's terminated on the buss.
