An energy-efficient residence in Mt. Airy, Maryland, USA, was monitored for aldehydes and radon in order to develop relationships between air infiltration rates and contaminant levels. One fifth of the measured formaldehyde concentrations were in the range that may cause health concerns. These concentrations were measured under very low air infiltration rates. Increased ventilation was effective in reducing high concentrations. Use of the heat exchanger led to an increase in the air infiltration rate which resulted in a substantial reduction of formaldehyde levels.
During the winters of 1982/83 and 1983/84, air infiltration measurements were made in 34 dwellings in 5 apartment blocks. In all 34 dwellings the air leakage of the building shell was measured by pressurization. In 5 dwellings tracer gas decay rate was used to measure the air change rate, both with andwithout mechanical ventilation. Results of these measurements are presented.
The Aardvark automated system has been developed for continuously measuring the air-exchange rate and 222Rn (radon) concentration in an occupied residence. The air-exchange rate is measured over 90 min intervals by tracer gas decay using sulphur hexafluoride as the tracer gas.
A simple means for determining air infiltration rates into homes and buildings for assessment of indoor air quality and energy conservation measures, based on a passive perfluorocarbon tracer (PFT) technique, was evaluated in a well-defined environmental chamber under experimental conditions of 1) constant temperature and ventilation rate, 2) constant temperature, variable ventilation
rate, and 3) variable temperature, constant ventilation rate.
The interpretation of the data presented in the named article (by Nazaroff W W et al, NO 1767) is extended to develop an improved model that can be used to predict radon concentrations in the single family house tested and possibly inothers as well. In particular, a more complete set of low sump activity data has been replotted.
The total air infiltration rates can be determined by the tracer gas decay method, but to measure the influence of inhabitants or convective exchanges between rooms, the constant concentration method is more suitable. In order tomeasure these effects, the Compact Equipment for Survey of Air Renewal (CESAR), developed at the LESO, was used to perform an air exchange analysis on data recorded at regular intervals in up to 10 locations simultaneously. Three tracer gas methods were implemented: decay, constant concentration and continuous flow.
A Compact Equipment for Air Renewal Survey (CESAR) has been developed by the Ecole Polytechnique Federale de Lausanne. The device has been designed for simultaneous analysis of up to 10 different inhabited rooms over extended periods of time (days or weeks). The constant concentration tracer gastechnique was used for the first survey done in the South rooms of the LESO building. Mean outdoor to room flow rates of between 1 and 40 m3/h were found.The mean building to room air flow was found to be 5 m3/h for rooms with only one communicating door with the rest of the building.
Concentrations of airborne radon ranging from 0.05 to 135 pCi/L were found in houses in Maine. Track-etch cups were placed in five positions for 100 houses to determine integrated average radon concentrations over the period October 1980 - May
Based on current concerns regarding indoor air quality and energy use, there is a need for in situ techniques for evaluating buildings' infiltration and ventilation characteristics. The U.S. National Bureau of Standards has developed and employed equipment and techniques for such evaluation. The measurement of whole building leakage and ventilation rates has been reported on previously. Additional procedures are presented here for a more complete evaluation of the ventilation system operation and the distribution of air within the building.
This paper describes a series of ventilation measurements carried out in two small factory units situated on an industrial estate in Newport, South Wales. One of the factories is typical of current design, and the other is designed to be of greater energy efficiency in terms of increased levels of insulation and reduced air infiltration rate.
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