Evaluation of evacuated glass tubes for sampling of SF6/Air mixture for air exchange measurements.

Grab sampling of a tracer gas/air mixture in conjunction with the tracer gas decay technique is a convenient method for conducting a survey of air infiltration rates in homes. Examines such a method, using SF6 as the tracer gas and storing the concentration in evacuated glass tubes.

Tracer techniques and data interpretation for infiltration measurements.

Describes a simple, inexpensive sampling technique for infiltration measurement using SF6 tracer gas. Uses pre-evacuated blood collecting test tubes with rubber stoppers for sampling. This is controlled by a micro-processor driven automatic sampler, which drives a hypodermic needle through the rubber stopper to fill the tube with an air sample. Analyzes samples using a gas chromatograph. Releases SF6 at ground level in a high-rise cold store and collects samples of air at different heights to see if stratification is present.

A field study of natural ventilation in better insulated houses.

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.

Cave climate: assesment of airflow and ventilation.

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

Sampling for air exchange rates in a variety of buildings.

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

The effect of tracer gas on the accuracy of air change measurements in buildings.

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.

An appraisal of the sulphur hexafluoride decay technique for measuring air infiltration rates in buildings.

Compares the air change rates measured with SF6 and CO2 using the tracer gas decay technique and the fan extraction method over a wide variety of test chamber sizes and mixing systems. Shows that the conventional air handling orportable floor fans can provide adequate mixing for SF6 tracer gas decay measurements of infiltration. Warns that the mixing operation may become the dominant driving force of infiltration during calm climatic conditions. Finds that +-0.08 ach/h is a reasonable measure of experimental error at the 95%confidence level using SF6 as the tracer gas.

Preliminary investigation into ventilation efficiency. Forundersogelse vedrorende ventilationseffektivitet.

The primary aim of the project is to describe and document a measurement method suitable for checking whether minimum requirements for ventilation efficiency are fulfilled after a ventilation system has been regulated. The project concentrates on occupied areas with mechanical ventilation such as dwellings,offices and schools. Excludes industrial buildings since special conditions such as ventilation rates, polluting processes and local extraction apply to these. Defines ventilation efficiency, describes equipment and measurement with CO2, N2O, SF6, Kr85.

Tracer gas in the USA. Spargas i USA

Describes the use of SF6 tracer gas measurement techniques employed in airtightness and ventilation research at Princeton in terraced housing. Notes use of measurement results for constructing models describing the total adventitious ventilation in a house. Refers also to similar techniques used in research at Berkeley in single family dwellings.

Air leakage measurements of an unpartitioned mobile home.

Reports measurements of air infiltration and air leakage of an unpartitioned mobile home, made in an environmental chamber. Infiltration was measured using sulphur hexafluoride as a tracer gas. Leakage was measured by depressurizing the mobile home. Discusses results and uncertainties in the air change rates. Examines dependence of air change on indoor-outdoor temperature difference. Compares results with previously published measurements and discusses anomalies.