thermography

Outlines the principles of infrared thermography and describes the equipment. Reports investigation at the National Swedish Institute for Material Testing into the use of thermography. Finds that the method should primarily be used as a relative method for plotting of building faults on external walls and for qualitative judging of their nature. It is not suitable for quantitative determination of the heat resistance of walls.Gives typical thermograms prepared using a test wall to which artificial defects were added.

Discusses ways of increasing accuracy and thoroughness of energy audits of buildings by use of specialized instruments and improved audit techniques. States air infiltration measurements are key item in audit procedure. Describes 'house doctor' kitwhich with records of past energy usage, knowledge of prevailing weather and a questionnaire are used to establish the energy signature of a house. The kit includes blower door, infrared camera, temperature probes and appliance consumption meter. Describes simple tracer gas method using sulphur hexafluoride collected in sample bottles.

Describes the two major methods of measuring air leakage in buildings; the tracer gas method and the pressure method. The three ways of using tracer gas are with decreasing gas concentration, constant gas concentration, and with constant gasrelease. In Sweden nitrous oxide is normally used. The results of the tracer gas method may depend on the weather at the time of measurement. The pressure method is fast and accurate, but only gives the total leakage through the building. Local differences can be detected by use of infrared photography.

Gives a summary of the work in building thermography in the scandinavian countries, especially Sweden. Deals with the principles of thermography, how to detect thermal resistance deficiencies and air leakage. Discusses applications in building and factors influencing the thermograms. Reviews test requirements in Scandinavia and discusses the results of measurements made on about 500 building projects.

Describes pressure method for testing whole houses for air leakage. States main advantages compared to tracer gas technique are that equipment is inexpensive, easy to handle and so well adapted to routine tests. The house is pressurized using a powerful fan and the flow through the fan is equivalent to the leakage through the building envelope at given pressure. Summarizes measurements made on test houses. and shows use of thermography to detect leaks. suggests use of pressure test to estimate the natural ventilation of a house.

Describes retrofitting a wood-frame residence, having only limited insulation in the attic, to reduce its energy requirements for heating and cooling. The three retrofit stages comprised : reducing air leaks ; adding storm windows : andinstalling insulation in the floor, ceiling and walls. The housewas extensively insulated to evaluate energy savings and other performance factors. an economic model was used to evaluate the cost effectiveness of the retrofit options.

The measurement systems used at Twin Rivers for determining energy usage are described. These include a weather station, three different systems for the measurement of temperatures and energy-related events in a house, a tracer-gas based air infiltration measurement system and infrared thermography