FLIR B6xx series User Manual page 248

28 – Introduction to building thermography
Access to the surface. Buildings where both the internal and the external surfaces
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are obscured, e.g., by false ceilings racking or materials stacked against walls may
not be amenable to this type of survey.
Location of the thermal insulation. Surveys are usually more effective from the side
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nearest to the thermal insulation.
Location of heavyweight materials. Surveys are usually less effective from the side
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nearest to the heavyweight material.
The purpose of the survey. If the survey aims to show risk of condensation and
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mould growth it should be internal.
Location of glass, bare metal or other materials that may be highly reflective. Surveys
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are usually less effective on highly reflective surfaces.
A defect will usually produce a smaller temperature difference on the outside of a
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wall exposed to external air movement. However, missing or defective insulation
near the external surface can often be more readily indentified externally.
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Publ. No. 1558550 Rev. a557 – ENGLISH (EN) – October 7, 2011