thermography

Illustrates some practical aspects of the use of one IR camera and associated equipment discusses some of the problems in interpretation of some pictures representing temperatures of the inside and outside surfaces of buildings particularly problems due to residual effects of the sun on external surfaces, reflection of sunlight into the IR camera, storage of heat from the sun in walls, and cold spots inside a building caused by heat loss by thermal bridges or cold-air infiltration.

Notes initial airtightness requirements in SBN 1980 and discusses various forms of ventilation. Discusses how tightness testing can reveal location and magnitude of leaks. Gives theoretical method of calculating air leakage flow and relates this to practical measurement. Considers different alternatives such as pressurising the building and combining tightness testing with thermography. Discusses 1980 building regulations and what buildings ought to be tested. Lists critical points of a building and measures which can contribute to good airtightness.

Reviews current methods of ventilation measurement in occupied buildings including tracer methods, pressurisation, and thermography. Gives criteria for good ventilation rate measurement techniques. Also explores new methods of measuring ventilation rates in occupied buildings. These include:< 1. Use of non-toxic tracers, including negative ions, CO2 and odour levels< 2. AC pressurisation< 3. The quantification of thermography< 4. Small-scale detection of local air velocities using hot-wire anemometry.

Assesses the quality of retrofit work carried out in 329 Swedish houses, which had received government energy-saving funds. Describes the selection of dwellings, the measurement methods employed (including thermography, pressure testing, tracer gas and heat flow) and the results.< In most houses, insulation work in attics and on external walls had been carried out satisfactorily. However, the houses were still not air tight and exhibited high ventilation figures (for pressure tests 8 air exchanges per hour at 50 Pa and for tracer gas tests 0.6 air exchanges per hour).

Reviews the overall aims and methods of the Conservahome Project, devised under the joint initiative of the Saskatchewan Office of Energy Conservation and the Saskatchewan Housing Corporation. The primary aims of the Project are to:< 1. Define the technical and economic problems of retrofit by conducting retrofit work on 6 houses< 2. Use the 6 houses as demonstration centres< 3.

The first part of the study describes thermography generally as a method for non-destructive testing of a building envelope for thermal and air tightness properties. The study has resulted in a two stage testing method of which pressurizing is an essential part. The field study has shown that thetwo-stage method is suitable in detection of air leakages, showing that the major part of thermal defects in the building envelope are due to air leakages.

An energy saving survey was carried out in an office building in Stockholm during the autumn of 1978. The measures which were proposed are now being carried out. This report details the measurements made which include, airtightness testing of the building, pressure drops across facades, air flow measurements, temperature measurements in ventilation systems, temperature measurements in rooms, boiler combustion efficiencies, electricity consumption, oil consumption and thermographic inspection.

Reports an investigation of the effects of temperature differences, pressures, sun and wind conditions on a thermal image produced by thermography. This investigation is concerned mainly with measurement points associated with air leakage. Reports measurements on a single-storey timber-framed house under a pressure difference of 5,-2,-10 and -20 Pa.

Discusses use of an instrumented energy audit, as opposed to a walk-through audit. Describes use of the audit to pinpoint infiltration sites. Method used is to depressurize a building and use thermography to locate air leaks. Briefly describes equipment and gives example of an instrumented audit of a residential building. States advantage of instrumented audit is that it gives a quantitative energy analysis as opposed to a qualitative one.

Presents the results from a major airtightness survey carried out in Norwegian dwellings. 61 detached houses and 34 flats were pressure tested. In 14 of the detached houses and 6 of the flats, leakage paths were traced using thermography. Gives tables of results. Lists most common leakage paths located by thermography. Occupants of the dwellings were interviewed about draught problems, but there was no clear correlation between occupant dissatisfaction and leakage rate. Notes a considerable variation in leakage between the houses.