The ventilation recommendations set out by the British Standards Institute Code of Practice, the Building Research Station Advisory Papers, and CIBS are outlined.
The structural design of glasshouses must provide for safety from wind damage while permitting maximum light transmission to the crop. A literature review of codes of practice, recommendations and data concerning wind loads on buildings showed several different procedures for describing the wind speed near the ground and predicting design pressures on low profile buildings.
Tests carried out during the sixties and seventies showed that there was a correlation between lung cancer and the existence of radon gas in mines and that there was radon gas in homes built of aerated concrete based on slate. This led to political activity with regulations for limits on emanation in new, re-built and existing buildings. Provisions were also made for grants to help house owners finance the improvements specified.< In the new bye-laws, SBN 80, gamma radiation is not to exceed 50 mu.R/h, the radon content is not to exceed an annual mean of 70 Bq/cu.m.
Ventilation measurements in new Swedish houses show that they seldom fulfill minimum requirements of 0.5 air changes per. hour applicable to specific housing classifications. Basic natural ventilation is often used. Discusses consequent problems including condensation and humidity, excess radon daughters and formaldehyde content in the room air. Notes future demands for systems to include heat exchangers.
Reports investigation whose object was to devise a quick and simple method for checking the airtightness of a whole building. Describes pressurization of building and gives results from 20 single family houses and five multifamily buildings. Finds that the majority of the multifamily buildings investigated conform to requirements in the regulations and about one half of single family houses satisfy the requirements stipulated for the transitional period.
Discusses actual ventilation rates in small houses and the requirements of Swedish building regulations. States that regulations do not take a total view of the energy balance in small houses, and pay no regard to the interplay between different forces.< Discusses a newly built 1.5 storey house as an example. Outlines problems in ensuring a low air change rate.
Describes the philosophy and formulation of the simple and detailed procedures for wind loading of the Canadian National Building Code of 1970. Defines design pressure in terms of the exposure of the building, its response to gusts, the mean velocity pressure and the structural shape of the building. Compares predictions of dynamic drag response and cladding pressures with full scale measurements on several tall buildings. Concludes that the predictions of drag response and windward pressure are satisfactory. Discusses area requiring further definition.
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.
Discusses reasons for making buildings air-tight and the requirements of the swedish building code. Gives examples of design solutions for detached houses and construction details for applying an internal vapour barrier consisting of a polythene sheet. Describes application to seven bungalows, resulting in air change per hour of 0.67 to 0.86. Subsequent measurements of ventilation and air velocity showed that in mechanically ventilated airtight houses the flow of ventilation air can be accurately controlled by the exhaust fan.
Reports investigation to devise a simple method for measuring the airtightness of buildings which will provide clear results in conformity with a definite standard, swedish building regulations 1975. Consists of two parts; field measurements comprising overpressure and tracer gas methods using nitrous oxide, and a theoretical calculation of the infiltration of air into a building. Shows that a test method to measure the airtightness of buildings can be developed.
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