nitrous oxide

Mathematical models for predicting indoor pollutant levels are being developed and compared with measured concentration in three residential dwellings - a relatively new townhouse constructed according to rigid energy-conservation guidelines,

Compares the air change rates measured using the decay method with several different tracer gases. The tracer gas measurements were conducted in atightly sealed room where constant air leakage rates, ranging from 0.05 to 1 air change per hour could be maintained using an exhaust fan. The tracer gases investigated were CH4, CO, CO2, N2O and SF6. The agreement between tracer gas measurements and measured flow rates of the exhaust fan was very good for CH4, CO and N2O.

The problems associated with the measurement of ventilation rates and air movement patterns in large single cell buildings which were unoccupied and unheated were investigated using the tracer gases nitrous oxide and sulphur hexafluoride. 

Carries out measurements of the air infiltration rate of 3 large single cell buildings using the tracer dilution method. The purpose is to determine whether or not there are any special difficulties in using the tracer dilution method in this type of building, prior to emabarking on a more substantial measurement program. Uses nitrous oxide and sulphur hexafluoride as tracers. Finds both to be satisfactory, but concludes that SF6 in conjunction with a portable gas chromatograph performs more reliably when used for on-site measurements.

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 a multi-channel infra-red gas analyser to measure nitrous oxide tracer gas concentration at six points round a house. Combines concentrations to give overall house ventilation rates and to estimate the air exchange between individual rooms. The gas analyser is also used to measure air movement between the house and its roof (with 5 sampling points in the house and one in the roof). Results show that typically 20-30% of the air that enters a houseleaves via the roof space through gaps in the ceiling.

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).

During an extensive programme of sound insulation tests on a house near Manchester Airport the opportunity was taken to measure the field performance of partially open dual glazing. The results show an increase in insulation of up to 3dB(A) when compared with predictions based on laboratory SRIs. Also reports measurements of the ventilation rate in bedrooms with one window partially open and all other doors and windows closed. Measurements were made using nitrous oxide as a tracer gas.

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.