Describes use of SF6 in tracer gas studies to determine solvent fumes in indoor and outdoor environments and how meteorological conditions affect SO2 content of atmosphere. Lists instrumentation used. Discusses properties of SF6 and properties required of a tracer gas, calibration and comparison of U.S. and Swedish results. Lists practical problems both general and specific to gas chromatography and factors affecting results. Suggests future development prospects stating advantage that lower concentrations of SF6 are required compared with N2O for examples.
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.
Give method for collecting and analysing sulphur hexafluoride used as a tracer gas. The gas is separated by gas chromatography from other components of moist air on columns of silica gel and activated carbon in series and is detected by electron-capture analysis in concentrations near 1 p.p.b. states that sensitivity can be enhanced at least 2000-fold by freeze-out concentration. States that SF6 backgrounds in air are undetectable except near leakage sources such as transformers.
Describes adaptation of photo-electrical optical technique to measure ventilation rates in wind tunnel models. Illustrates probe photographically and diagrammatically. It comprises essentially a light-emitting diode and a hybrid photodiode-amplifier detector. Compares technique with conventional tracer gas technique using helium and a katharometer and finds good agreement. Considers optical probe has considerable potential for measurements in small and multi-celled models where conventional techniques are not feasible.
Suggests the use of sound waves to locate openings in buildings that allow air infiltration. Reports results of an experimental program, including laboratory tests of a specially constructed partition and field tests on eight buildings.
Describes experimental techniques used in the low-speed wind tunnels at the Building Research Station when studying air flow around buildings and pressure distribution over their surfaces. Includes flow visualisation both in the stream and in boundary layers over surfaces, velocity measurements around small-scale models, and methods of building models containing pressure tappings. Gives names of suppliers and details of some instruments and equipments. Describes in an appendix how a simply constructed heated-sphere anemometer is made.
Describes automated instrumentation using sulphur hexafluoride as a tracer gas in residential housing to determine rates of air infiltration in houses. Discusses in detail the principles of operation, necessary calibration procedures and early field data. Concentration levels of SF6 are maintained at the partsper million level in the buildings and are measured by sensitive electron capture detectors in conJunction with a gas chromatograph.
Describes a research project undertaken at the Building Research Station to measure wind pressures on the G.P.O. tower, London, and dynamic strains in the tower shaft. The development of a suitable pressure transducer which used strain gauges as sensors is described, together with the installation at the tower. some othe problems of strain gauging large civil engineering structures are outlined. NOTE Final results of this project are given in "Wind pressure and strain measurements at the Post Office Tower" Newberry C.W. Eaton K.J. Mayne J.R. abstract no.229. B.R.E. C.P. 30/73
States direct observations of wind effects on real buildings are necessary for the development of reliable information for wind load estimation. Their essential role is to provide data for the guidance of systematic wind-tunnel investigations. Briefly reviews instrumentation used in a particular tall building and the methods employed to interpret the measurements. The review illustrates the potential, as well as some of the problems of field measurements in providing practical information about wind loading phenomena. Summarizes results and discusses their implications for design.
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