Thermal Imager Rental – A Smart Alternative
Tip written by: Infraspection Institute
With prices ranging to over $10,000, a thermal imager can represent a considerable investment. For companies getting started in thermal imaging, renting an imager can provide a cost effective alternative to purchasing a system outright.
Whether you are facing an equipment shortage or looking to evaluate the characteristics of a new imager prior to purchase, renting a thermal imager may provide a solution. In some cases, imager manufacturers will credit short term rental fees toward the purchase price of an imager. As with purchasing an imager, there are several important things to consider when arranging for a rental unit.
To help ensure that you select an appropriate imager for rental, be certain to:
- Identify appropriate spectral response required for project
- Determine if temperature measurement is required
- Evaluate the system for objective specifications
- Ascertain imager compatibility with reporting software
When arranging for a rental, obtain terms and conditions from the rental agency. These should include, but not be limited to: rental period, extension of rental, shipping costs, and requirements for insurance against loss. One should also consider the rental agency’s ability to provide technical support during the rental period.
For more information on choosing an infrared imager, refer to the article, “Selecting, Specifying, and Purchasing a Thermal Imager” available as a free download on this website.
Lastly, the greatest limiting factor in any infrared inspection is the thermographer. For accurate results, infrared inspections should only be performed by properly trained and certified thermographers. For more information on thermographer training and certification, please contact Infraspection Institute.
Asphalt or Coal Tar – How to Tell the Difference
When performing an infrared inspection of low slope roofing systems, invasive testing is necessary to confirm the composition and condition of roofing system components. As asphalt and coal tar are incompatible materials, it is imperative to use the correct bitumen to ensure the long term integrity of repaired test sites.
Asphalt and coal tar are hydrocarbon materials commonly used for built-up roofing. While both share a common use in roofing, they are very different in their chemical composition. Asphalt is a petroleum distillate and a byproduct of crude oil refining. Coal tar is a bituminous product that is largely insoluble in petroleum distillates.
Odor is one way to differentiate between asphalt and coal tar – tar has a distinctive creosote smell. A more reliable method is to test bitumen solubility in mineral spirits. This simple test can be performed as follows:
- Obtain a small sample (pea size nugget) from the subject roof
- Soak sample in a small amount of mineral spirits in an empty glass container such as a baby food jar
- Stir sample gently for about one minute and note results
If sample dissolves to black liquid – sample is asphalt; if sample remains intact and/or colors mineral spirits to a yellow/green color, sample is coal tar.
Once bitumen type has been determined, one should use appropriate repair materials along with the same bitumen as indicated by the above test. Doing so will help to ensure the long term integrity of repaired test sites.
Infrared inspection of flat roofs is one of the many topics covered in all Infraspection Institute Level I training courses. For more information on thermographer training or to obtain a copy of the Standard for Infrared Inspections of Insulated Roofs, visit Infraspection.com or call us at 609-239-4788.
Splash Protection for Your IR Imager
Taking your infrared imager into dusty or wet environments can have disastrous consequences for your imager. While it is best to wait for such conditions to subside, you can use a polyethylene sheet or trash bag to temporarily protect your imager and accomplish a qualitative inspection.
Since not all imagers and trash bags are created equal, you can follow the following steps to ensure good results.
- Set up imager looking at a thermally stable target with a high emittance. If using an imaging radiometer, note the apparent temperature of the target.
- Select a clean, unused, polyethylene trash bag with a uniform thickness.
- Open trash bag and place over imager. Use only a single layer of the bag plastic to cover the lens.
- Use a rubber band to keep plastic smooth and wrinkle free over the imager lens.
- Image target in Step 1 again and note image quality and apparent temperature.
- Repeat above steps using different brand bags and thicknesses until you find a bag that gives minimal attenuation of image and apparent temperature.
- After selecting the bag that works, trim to fit imager so as to prevent a tripping hazard. If your imager requires air cooling, leave the bottom of the bag open so the imager can ‘breathe’.
- When finished imaging, remove bag from imager and discard.
While not glamorous, this procedure can allow you to successfully perform a qualitative inspection in an environment that might otherwise harm your imager.
Infrared equipment selection and operation are two of the many topics covered in all Level I Infraspection Institute Certified Infrared Thermographer® training courses. Level I training is available at several locations each month and through our Distance Learning Program. For information on thermographer training including course locations and dates, visit us online at www.infraspection.com or call us at 609-239-4788.