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.
Steeply sloping ventilated roofs are preferred for single and two-family houses in West Germany. Notes lack of any scientifically substantiated notions concerning physical laws governing air exchange between ventilated zones and outside air. Describes air flow and heat transfer investigations in a 48 deg. sloping roof. Gives details of roof constructions. Illustrates roof space and distribution of thermocouples and arrangement for injecting tracer gas. Describes experimental procedure. Provides some measurement results. Compares theoretical bases with experimental results.
Reports tests of the effect of various air treatment devices on the radon daughter concentrations within a room. Test were carried out using an electrostatic precipitator, a humidifier and a dehumidifier. The ventilation rate of the room was measured using Krypton 85 as a tracer gas.< Finds that the use of a humidifier, dehumidifier or carbon filter gave no significant alteration to the radon concentrations in the room, but that the electrostatic precipitator reduced the concentration considerably and was equally effective when operated with or without the carbon filter.
Discusses energy saving measures taken in the Ekono office building, headquarter of Ekono consulting engineers, situated near Helsinki. Describes the use of hollow slabs for intermediate floors, tight window construction, the extract air window system, efficient lighting and computer control of ventilation. It is planned to control ventilation by monitoring the concentration of carbon dioxide in the building. Reports measurements of infiltration rate with nitrous oxide as a tracer gas using both constant concentration and decay rate techniques.
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