Gives results from fiel trials of the performance of various mechanical ventilation systems. Carries out measurements in buildings built during the seventies, using the tracer gas decay technique with N2O. Tests 3 cases:< 1. Air supplied only through register above door< 2. Air supplied both through register and the slot under the door< 3. Air supplied only through slot under the door.
Reports on 2 methods of measuring ventilation rates in the 8-storey San Francisco Social Services Building, using occupant-generated CO2 as a tracer gas. Measures CO2 concentration at regular intervals on the first floor using an infra-red gas detector. Uses the tracer gas decay method and the constant concentration (integral) method to determine ventilation rates. Finds that the CO2 decay method compares favourably with both SF6 tracer gas measurements and with air-flow measurements in the ducts.
Outlines a method for measuring air infiltration using the tracer gas decay technique. SF6 is introduced into a building, and once it is well mixed, container samples of air (in this case plastic bottles) taken over a period of time are analy
Reports the results of over 100 tests of 6 different warm air schemes. The temperatures and the removal of a tracer gas were monitored at several points and the data used to determine the temperature efficiency and ventilation efficiency. For ea
Compares the air change rates measured using the decay method with several different tracer gases. Tracer gas measurements were conducted in a tightly sealed room where constant air leakage rates were maintained using an exhaust fan. Tracer gases investigated were CH4, CO, CO2, N2O and SF6. Agreement between tracer gas measurements and measured flow rates of the exhaust fan was very good for CH4, CO and N2O. The agreement was also satisfactory for CO2 and SF6, but the scatter in tracer gas data was much greater then it was for the other three gases.
Describes the measurement of infiltration and air change rates in one flat in an apartment block containing 24 flats. Gives the general principles of the pressurization method and tracer gas method for measuring air change rate and infiltration rate. In this situation uses N2O as the tracer gas and measures concentrations with an infra-red gas analyser. Measures the effects of opening and sealing windows, and of closing internal doors on the air change rate and air movement in the flat.
Uses occupant-generated CO2 as an indicator of the actual ventilation rate in a San Francisco office building. Employs two techniques, a decay method and an integral method, and measurements are conducted simultaneously at several locations. The decay method compares favourably with the conventional measurement methods in both the all-outside-air and recirculation modes, whereas the integral method shows a considerable deviation from the other methods in the recirculation mode.
Gives a brief overview of:< 1. Measurement of air change rate using tracer gas.< 2. Measurement of air leakage using steady state and alternating pressure.< 3. Calculation methods (by hand and by computer) for predicting air exchange in a building.< Indicates where relevant research in these areas is being carried out, and outlines the role of the Air Infiltration Centre.
Reviews current methods of ventilation measurement in occupied buildings including tracer methods, pressurisation, and thermography. Gives criteria for good ventilation rate measurement techniques. Also explores new methods of measuring ventilation rates in occupied buildings. These include:< 1. Use of non-toxic tracers, including negative ions, CO2 and odour levels< 2. AC pressurisation< 3. The quantification of thermography< 4. Small-scale detection of local air velocities using hot-wire anemometry.
Lists three factors causing a high radon and radon daughter concentration in Swedish dwellings:< 1. By energy-saving measures the ventilation rate has become low.< 2. 10% of existing houses are built of light-weight concrete with a high proportion of radium.< 3. Large regions have high radium content in the ground.< Describes a method for detecting high radon daughter levels by measuring gamma radiation from the outside.
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