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High E Targets for Measuring Component Temperatures
Tip written by: Infraspection Institute

Low emittance can introduce significant error when performing non-contact temperature measurements of electrical and mechanical system components. Affixing high emittance coupons to component surfaces can provide a solution.

Temperature measurements are often useful in assessing the condition of components and systems. Because many electrical and mechanical components are constructed of shiny metal, obtaining accurate infrared temperature values is often impossible. Affixing coupons of tape or paint with known emittance values is a proven method for increasing measurement accuracy.

There are a number of inexpensive materials that can be used to modify component surfaces. These include Scotch 191 PVC tape (E 0.97), and Wahl flat black paint (E 0.95). Affixing coupons of these materials to areas of interest provides a known emittance and ensures that future temperature measurements are made in the same spot.

Prior to modifying any surface, keep the following in mind:

• Always obtain permission to modify any component(s)
• Ascertain that subject surfaces are safe to touch
• Check target temperature to ensure modifying material will not melt or catch fire or damage the component
• When using tape, be sure to install without air gaps
• Ensure that coupon is sufficiently large for intended radiometer’s spot size

Lastly, contaminants from industrial environments can cause the emittance of modifying materials to change over time. If so, it may be necessary to reapply the modifying material periodically.

Infrared inspection of electrical and mechanical components is one of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information or class locations and dates, visit www.infraspection.com or call 609-239-4788.