Describes some new theoretical and experimental techniques developed by British Gas to investigate the ventilation of buildings. These include:< 1. The multi-cell model "vent" for predicting ventilation rates< 2. "Autovent", the multi-cell constant concentration tracer gas technique used for measuring ventilation patterns in buildings.< 3. Pressurization techniques for measuring air leakage in buildings.< Gives a selection of results from applications of these techniques to show their scope.
Describes method which permits long term tracer gas measurements in several separate rooms simultaneously. The method employs a fully automated constant concentration system developed at the laboratory for building physics at the Swedish Institute for Materials Testing. Describes measurement principles andpractice.
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.
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.
Reports on a measurement system developed by the Institute of Technology at Tastrup Denmark, involving a microcomputer- controlled system for registering air change rates using tracer gas (nitrous oxide) according to the constant concentration method. The system is designed for measuring and metering tracer gas in up to 10 separate rooms (using an infrared gas absorption detector). It operates through automatic data logging on a floppy disc and can run without supervision for extended periods (up to six days).
Gives a summary of the existing types of air infiltration measurement techniques and instrumentation using tracer gases. Describes automated air infiltration instrumentation used by researchers in the US, Canada, the UK, Denmark, Sweden and Switzerland. The equipment can operate in the decay mode, constant flow mode and the constant concentration mode.
Measures the air infiltration in individual rooms of a one-storey airtight house, using a special tracer gas measurement technique. Concludes that the overall ventilation rate was very low for the test house, although it had mechanical ventilation (exhaust fan). States that the best way of getting adequate ventilation is to install a ventilation system with built-in routes where fresh air can enter the building. This should either be balanced ventilation system or an exhaust fan system with special vents to the outside for supplying fresh air.
Describes methods used at ECRC for measuring the ventilation rate in houses. Two tracer gas methods are used, the decay method and the constant concentration method. Measurements have been made using both nitrous oxide and carbon dioxide as tracer gases. Also describes test of air leakage made by pressurizing the entire house. Gives for each method a detailed description of the measurement technique.
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.
An automated air infiltration measurement system for large buildings isdescribed. The system consists of a micro-computer, electron capture gaschromatograph, a ten port sampling manifold, and five tracer gas injectionunits. The system controls the injection and sampling of tracer gas in amulti-zone building, calculates the air infiltration rates of each zone, andmeasures the on-time of events such as HVAC fan operation, exhaust fan operation,and door/window openings.
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