English

Presents a new method for determining the airborne concentrations of RaA, RaB and RaC in atmospheres contaminated with radon-222. The method employs alpha spectroscopy to measure the count rates of RaA and RaC' present on a membrane filter sample at two post-sampling times. The individual air concentrations and the statistical variances associated with each may then be calculated from the equations given. Presents theoretical and experimental comparisons which indicate the improved accuracy of the spectroscopic method over methods previously available.

Gives results of a statistical survey of energy consumption in British government buildings. Suggests one reason for high consumption may be excessive ventilation. Reports field trial of the effect of reducing natural ventilation in a London office building. Window frames were sealed with a rubber mastic, giving an annual fuel saving of 22%. Finds measure was highly cost effective with a payback period of less than three years.< Discusses problem of heat loss through large doors in hangars and workshops.

With increased concern for energy conservation, many new standards have been developed. Discusses these standards which are of three types, prescriptive, component performance and performance. Outlines several design approaches toreducing air infiltration.

Discusses flow of air between two rooms through an open door. Considers 6 cases with and without mechanical ventilation and with a temperature difference between the two rooms. Gives examples of the calculation of air flow. Recommends that for hospitals where the transfer of bacteria should be avoided, doors should be kept shut as much as possible and that it is not economically justifiable to choose such a high ventilation rate that no undesirable back flow occurs with the doors open.

Four two-storey four-bedroom test houses were built in 1974 near Columbus, Ohio and have been instrumented and monitored by Ohio State University. All four houses are unoccupied. Air infiltration rates were measured in all four houses using sulphur hexafluoride as a tracer gas and two of the houses were pressure tested for air leakage. Discusses results and the correlation between infiltration, inside-outside temperature difference and wind velocity. Compares tracer gas results with pressurization tests.

In order to reduce heating energy consumption, single glazed windows are commonly replaced by double glazing and joints tightened in Danish dwellings. Reports investigation of the influence of such tightening of dwellings on the indoor climate. 25 tightened and 25 not-tightened identical flats were investigated. Finds an improvement in thermal climate and a significant reduction in heat consumption in the retrofitted flats. Finds absolute humidity of indoor air was significantly higher in improved flats, probably due to reduced ventilation.

An earlier paper gave the flow to be expected through an open door from theoretical considerations. Describes model tests designed to check these theoretical predictions. The model used was 6.3% of full size and water was used instead of air for the flow medium. Concludes there is reasonably good agreement between model and theory.

Discusses the tracer dilution method for measuring air change rates. The technique entails introducing small amounts of tracer gas into a building and measuring the rate of change in tracer concentration. Describes the method and compares different tracer gases. Outline ways of obtaining an estimate of the air infiltration from experimental data. An appendix discusses the errors in the procedure.

Notes that altering interior moisture content of a building can influence both energy use and other performance characteristics. Gives an assessment of the moisture interaction as related to health and comfort of the occupants, fire safety, durability and maintainability and design and construction of light-frame housing. Reviews published recommendations.

Reviews the state of the art in the measurement of ventilation and air infiltration. Considers tracer gas techniques and discusses some of the tracer gases used as well as some of the potential sources of error. Also discusses fan pressurization-evacuation procedures for measuring building tightness and compares fan and tracer measurements. Discusses the ASHRAE crack method.