Uses a two-region model to predict infiltration, to take into account non-ideal mixing of tracer gas in a building. Considers versions of this model:< 1. Fluid flows between the 2 regions and the environment in any manner provided steady state and mass balance are maintained.< 2. There is limited interchange between the regions< 3 Air flows into the first region and out of the second with (unbalanced) interchange between the two.< 4. The second region is a "dead-water" zone, which is not directly connected with the outside.<5.
Describes air leakage and tracer gas (SF6) measurements made in 42 Scottish houses. Finds that leakage in the "test" (better insulated) houses are on average 10% higher than that in the "control" houses. About 40% of the total leakage rate (at a pressure difference of 50 Pa) flows into houses through thefloor boards and the air-bricks under the crawl spaces. Tracer gas measurements indicate that average leakage rates with closed windows lie between 0.52-1.65 air changes per hour. Opening a window can increase the number of air changes by a factor of 2 to 5.
Reports on an extension of the metabolic CO2 method for ventilation measurement to a naturally ventilated room having air flow connections with other internal spaces as well as the outside. Uses an infra-red gas analyser to monitor CO2 concentrations in the fresh air outside and also within theroom, the corridor and the ceiling space. An automatic unit switches the analyser between 6 sampling points. Comparison of the data with results from SF6 tracer gas decay methods gives close agreement.
Describes a technique for measuring air flows between internal zones of houses. Gives the theory of measuring one and two directional flows and describes the equipment used for practical measurements. Uses Freon 12, Freon 114 and BCF as tracer gases, and measures their concentrations using a gas chromatograph. Includes specimen results of one and two directional flows between a house and its roof. Discusses the possible applications of the method in houses.
Using miniature perfluorocarbon tracer (PFT) sources and miniature passive samplers, tests conducted in the lab and in a typical home successfully demonstrate the utility of the PFT kit as a means for implementing wide-scale infiltration meas
Examines airflow in the Glowworm cave of New Zealand using conventional methods together with experimental procedures using SF6 and CCL2F2 tracer gases. Results show that the rate and direction of airflow are a direct response to a thermally
Uses the SEGAS "Autovent" constant concentration apparatus to measure the fresh air entering and the local ventilation rate in each cell of amulti-celled dwelling with both natural and mechanical extract ventilation. Measures fresh air entry into each cell using tracer gas constant concentration and decay techniques. Conducts decay tests without artificial mixing, and interprets them by computing the area under the decay curve to obtain local ventilation rates. Compares the 2 measurements, giving the ventilation efficiency of each cell and an idea of air quality in each room of the house.
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
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