Considers that air change measurement by means of tracer gas is the best way of measuring natural air infiltration in buildings. In some cases the method can be useful for measuring the ventilating air rate in mechanical systems asno interference with the system is required by the method. Deals with the theory of the method, the handling and measurement of different gases, cost of gas and instruments. Concludes by saying that only very simple instrumentation is required for most of the measurements with satisfactory accuracy.
Reports measurements of air leakage rates in the four energy-conservation research houses using the fan pressurization method. One of the houses is standard for the area and the other three houses have added insulation and vapour barriers. One house has a heat pump and one an air-to-air solar heating system. Air infiltration rates were measured in two of the houses using CO2 as a tracer gas. Discusses results and compares tracer gas with pressurization tests.
Reports findings of investigations carried out by West German Federal Ministry of Health in July 1978 into the internal climate in the one third of the rooms in a representative West Berlin school which are located in the building core. These rooms have mechanical ventilation and artificial lighting. Gives results of measurements of room temperatures, air change rates, (measured using N2O as a tracer gas), concentration of carbon dioxide and acoustic performance of the rooms.
Assesses the role of natural ventilation in modern hospitals. Considers optimum standards of air change rates for winter and summer conditions and reviews factors within the hospital context that are likely to affect the achievement of natural ventilation. Notes an air change rate of 1.5/hr. is usually assumed for heat loss calculation. Finds cross ventilation is unlikely to be achieved and designs should be based on single sided ventilation. Reports tracer gas measurements of natural ventilation in Southland Hospital, Shoreham by Sea.
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.
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.
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.
The Alberta Home Heating Research Facility consists of six uninhabited wood frame single storey modules with full basements. Describes the modules which are designed to test domestic heating strategies in a northern climate. Reports a series of preliminary measurements of infiltration rate using SF6 as a tracer gas and measuring the rate of decay of the gas. Future studies are planned using SF6 in constant concentration.
Describes the operating characteristics of a small aspirated concentration sensor based on a hot-film anemometer. Constant aspiration velocity past the sensor produces a linear output over a wide range of tracer gas concentrations, and a useful bandwidth of 0-500 Hz. A simple experimental technique for dynamic calibration is presented, with frequency response inferred from a model of the effects of molecular diffusion and hot-film response.
Outlines factors influencing natural ventilation rates. Discusses techniques for measuring natural ventilation. Gives results of pressure measurements, made by the Building Research Establishment, of the leakage of houses and of tracer gas measurement of room ventilation rates. Discusses variation in air leakage rates with time. Gives results of measurements of the distribution of air leakage between components of the building shell.
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