Building Thermography – Thermal Imaging
Building inspection is a fast-growing application of infrared thermography, which can be used to test and solve problems in buildings of any age, size, use or construction type. The key benefits are that it allows non-destructive and non-contact assessment of the structure’s and/or location and size of defects within building structures, components or systems to be carried out. With suitable equipment, large areas of buildings can be scanned and assessed in a relatively short time.
Thermography is still an emerging technology across the construction industry, with growing levels of awareness and an ever-increasing number of applications, but relatively little real understanding of what it can and cannot provide, and how and when to use it effectively. One of the most important factors with thermal imaging of buildings is consideration of weather and environmental conditions, which can in many cases be critical to successful use.
Architects, builders, facility managers, surveyors, loss adjusters and many other building professionals, as well as individual home owners, can benefit from thermal imaging surveys. The key uses are summarised below.
Building fabric heat loss
One of the best known uses for building thermography is to assess thermal insulation (as required by Part L Building Regulations) and other key sources of heat loss such as thermal bridging and excessive air infiltration around the building fabric. It can be very useful to use a ‘blower door’ (used to test the air tightness of buildings) together with thermal imaging to locate the sources of draughts and interstitial air movement. The weather and environmental conditions are critical for heat loss surveys; a cold and dry morning is generally required, prior to sunlight warming the building, so inspection typically can take place between September and May in the UK. Wherever possible, internal scans should be performed to fully understand heat loss and its likely mechanisms. A great deal of caution should be
applied where external-only scans are recommended, since, in many cases, the location of external ‘hot spots’ may not necessarily identify the corresponding internal ‘cold spot’. Surveys incorporating both internal and external thermal imaging are of course more time consuming and complex but, in general, only a basic impression of a building’s thermal performance can be determined from an external survey.
Structural damp and leak tracing
Structural damp and leak tracing is very valuable for building owners, managers and many construction professionals.
Thermal imaging provides non-destructive investigation to locate areas that are damp and often enables the sources of damp to be identified, whether they be in the roof, walls, floors, windows or doors. Additional specialised equipment is often required to assist in this process and verify suspected damp. Depending on the particular situation, the weather conditions may be important and should be considered by the thermographer.
Plumbing, heating and ventilation systems can be tested for performance, location (for example the precise position of under floor heating systems) or leaks. Generally, these surveys are not weather dependent.