User's Manual

■ Infrared inspection does not directly detect the presence of mold, rather it may be
used to find moisture where mold may develop or has already developed. Mold
requires temperatures between +4°C to +38°C (+40°F to +100°F), nutrients and
moisture to grow. Humidity levels above 50% can provide sufficient moisture to
enable mold to grow.
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Figure 27.2 Microscopic view of mold spore
27.3.1.3 Guidelines for detection of air infiltration & insulation deficiencies
■ For very accurate camera measurements, take measurements of the temperature
and enter this value in the camera.
■ It is recommended that there is a difference in pressure between the outside and
the inside of the building structure. This facilitates the analysis of the infrared images
and reveals deficiencies that would not be visible otherwise. Although a negative
pressure of between 10 and 50 Pa is recommended, carrying out the inspection
at a lower negative pressure may be acceptable. To do this, close all windows,
doors and ventilation ducts and then run the kitchen exhaust fan for some time to
reach a negative pressure of 5–10 Pa (applies to residential houses only).
■ A difference in temperature between the inside and the outside of 10–15°C (18–27°F)
is recommended. Inspections can be carried out at a lower temperature difference,
but will make the analysis of the infrared images somewhat more difficult.
■ Avoid direct sunlight on a part of a building structure—e.g. a façade—that is to be
inspected from the inside. The sunlight will heat the façade which will equalize the
temperature differences on the inside and mask deficiencies in the building structure.
Spring seasons with low nighttime temperatures (±0°C (+32°F)) and high daytime
temperatures (+14°C (+57°F)) are especially risky.
86 Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011
27 – Introduction to building thermography