How Dust Creates Full Size Thermal Imagery
Tip written by: Infraspection Institute
When performing an infrared inspection of the interior of a building, you may be able to visually observe full-size thermal images without your thermal imager. The cause of this phenomenon is simple dust and dirt normally found within most buildings.
Many buildings employ cavity wall details in the construction of interior spaces. When the exterior of framed walls are exposed to cold temperatures, areas with diminished R values will cause the interior surfaces of the wall to cool. Such cold areas may be caused by framing members or wall cavities with missing or damaged insulation.
If interior humidity levels are high and outdoor temperatures sufficiently low, moisture will condense on the wall surfaces within the occupied spaces. Once moisture condenses on the wall surfaces, dust and smoke particles can collect in these areas and will remain once the wall surface has dried.
Thermal patterns caused by dust and condensation are readily observed for light-colored walls with smooth surfaces such as drywall coated with smooth latex paint. The intensity of the resulting dust patterns will be dependent upon humidity levels, wall temperatures, and the amount of particulates within the air.
Typically dust patterns are more intense within areas occupied by smokers, within kitchens, near woodstoves or fireplaces, or in areas where candles are burned. Over time, dust patterns can become quite pronounced and will often clearly show every framing member and insulation deficiency within the wall.
Infrared inspection of building envelopes is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training including course locations and dates, visit us online at www.infraspection.com or call us at 609-239-4788.