Sulphur hexafluoride as a gas-air tracer.

Give method for collecting and analysing sulphur hexafluoride used as a tracer gas. The gas is separated by gas chromatography from other components of moist air on columns of silica gel and activated carbon in series and is detected by electron-capture analysis in concentrations near 1 p.p.b. states that sensitivity can be enhanced at least 2000-fold by freeze-out concentration. States that SF6 backgrounds in air are undetectable except near leakage sources such as transformers.

Air exchange measurements in a high-rise office building.

Reports measurements of air change rates made in the tower of an eleven-storey building using sulphur hexafluoride as a tracer gas. Inside to outside pressure differences were also monitored as a function of temperature and wind speed. Gives expression for autumn and winter air change rate as a function of windspeed. Reports finding that wind direction and stack effect had little effect on the air change rate. In this building toilet exhausts and other weather independent mechanisms were more important than natural infiltration.

A low-cost method for measuring air infiltration rates in a large sample of dwellings.

Presents method for collecting air infiltration data in a large sample of dwellings. The method consists of a tracer gas dilution technique using sulphur hexafluoride and employing air sample bags which are analyzed in a central laboratory. Themethod is easy to perform and inexpensive and will be used in approximately 300 dwellings on 16 sites to give air exchange rates under typical heating season conditions. Presents preliminary data on air infiltration rates in low-income housing in Portland, Maine.

Automated instrumentation for air infiltration measurements in buildings.

Describes automated instrumentation using sulphur hexafluoride as a tracer gas in residential housing to determine rates of air infiltration in houses. Discusses in detail the principles of operation, necessary calibration procedures and early field data. Concentration levels of SF6 are maintained at the partsper million level in the buildings and are measured by sensitive electron capture detectors in conJunction with a gas chromatograph.

Retrofitting an existing wood-frame residence for energy conservation-an experimental study

Describes retrofitting a wood-frame residence, having only limited insulation in the attic, to reduce its energy requirements for heating and cooling. The three retrofit stages comprised : reducing air leaks ; adding storm windows : andinstalling insulation in the floor, ceiling and walls. The housewas extensively insulated to evaluate energy savings and other performance factors. an economic model was used to evaluate the cost effectiveness of the retrofit options.

Use of a portable gas chromatograph and tracer gas for rapid determination of air ventilation rates

Describes method of measuring the air-change rates using sulphur hexafluoride as a tracer gas. The system comprises a highly portable gas chromatograph with an electron capture detector. The system will detect tracer gas without interference from other materials which may be present. The technique takes about six minutes to determine the ventilation rate. Gives practical examples and suggest extensions of the technique for carrying out cross air movements, for example in a hospital.

An intercomparison of tracer gases used for air infiltration measurements.

Reviews ideal characteristics of a tracer gas and gives literature review of the subject. Reports tests made on a house in California giving a direct intercomparison between common tracer gases used to measure air infiltration rates in buildings. Results indicate that air exchange rates measured using sulphur hexafluoride are slightly larger than thosemeasured using methane or nitrous oxide. The ratio of air change rates measured using sulphur hexafluoride to air change rates measured concurrently using a lighter tracer gas was found to be 1.10 +/- 0.10

Energy conservation in an old 3-story apartment complex.

Reports study of the potential for energy saving in an old low-rise, 50 unit apartment building. Energy use and heat balance of the building are calculated including heat loss through conduction and air infiltration. Also gives estimate of infiltration rate from a room found using first water vapour thensulphur hexafluoride as a tracer gas. Suggests various strategies for energy conservation which would result in a 30% saving in fuel. Methods are applicable to a wider class of old buildings

Comparison of measured and computer-predicted thermal performance of a four bedroom wood-frame townhouse.

Measurements of the dynamic heat transfer in a four-bedroom townhouse were made under controlled conditions in a large environmental chamber to explore the viability of a computer program developed at N.B.S. labelled NBSLD for predicting heating and cooling loads and inside temperatures. Test house was factory-produced, of modular design and lightweight (wood) construction. Tests were performed with simulated outside summer, winter and autumn diurnal temperature cycles. Inside temperature was maintained at 75 f and the activities of a six-member family were simulated.

Ventilation measurements in the Norris Cotton Federal Office Building in Manchester, NH

Reports measurements of ventilation rate in specially designed low energy office building. Air change rates were measured using sulphur hexafluoride as a tracer gas and air samples were analyzed for carbon dioxide. Gives tables of results. Discusses analysis of ventilation from CO2 data. Concludes that most of the spaces in the building were operating at or above recommended levels.