English

For more than two years a series of detailed air infiltration measurements have been conducted over the complete yearly weather cycle on two identical side-by-side test houses in Gaithersburg, Maryland, USA. These measurements have been part of a broad study of the interaction of air infiltration , indoor air quality and energy in tightly constructed, well-insulated homes. The standard method of collecting air infiltration data throughout the study has been tracer gas decay. Operation of the duct air circulation fans has transformed each house into a single well-mixed cell .

The effects of operating unvented appl i ances and opening windows on indoor pollutant levels and air exchange rates are being studied under the sponsorship of the Gas Research Institute. The study is being conducted i n an instrumented, well-characterized bilevel house located near Washington, D.C. Air leakage due to window openings is characterized by pressurization measurements and the air exchange increment is characterized through tracer gas measurements. Two unvented space heaters, one radiant and the other convective, are operated singly and in combination with a gas cooking range.

Pacific Power and Light Company and Battelle PNW Laboratories have completed a project which investigated residential ventilation rates. The results presented in the report discuss evaluation of methods used to measure ventilation rates, the behavior of ventilation rates in residences and the comparison of ventilation rates among home construction types. The perfluorocarbon tracer gas decay technique for measuring ventilation rates was concluded to be the best method used during the testing.

The air infiltration component of house ventilation is calculated and discussed in relation to winter space heat losses and rneasures necessary to control moisture. The airtightness of 80 houses sampled from three major urban areas was inspected for association with location, external cladding materials, and design features such as the shape and complexity of the building envelope. A useful correlation of airtightness with envelope complexity emerged which gives a coarse but useful way of forecasting airtightness from building design information.

In this paper ventilation of attics and crawl-spaces is investigated theoretically. Ventilation rates and temperatures of the spaces are calculated by means of flow balance procedures. Flow characteristics of ventilators and openings for attics and crawl-spaces are far from well known, so a laboratory investigation on pressure drops across such devices was undertaken and reported in the paper. As convective flows from the heated part of a houseinto a colder, ventilated space can create moisture problems this situation has been investigated extensively.

This paper describes a preliminary investigation of the validity of a means of calculating the ventilation rate of a large enclosure from experimental data. It was assumed that the air in the enclosure is not perfectly mixed. The measurement method selected was tracer gas concentration decay. Thecalculation of ventilation rate was performed by "least squares" fitting of a model to the observed tracer gas concentrations. Simulations of tracer gas concentration decay measurements were performed with varying initial distribution of tracer gas.

Reviews the papers on air infiltration and ventilation research presented at the ASHRAE annual meeting held in Honolulu, Hawaii, in June 1985. The twelve most significant papers on multizone infiltration and air leakage are discussed at length and other infiltration-related papers mentioned. Authors' abstracts for the twelve symposium papers plus seven technical papers are presented.

Several physical phenomena which may contribute to moisture migration from the crawl space to the living spaces in houses are outlined. Results of two projects to monitor moisture migration are presented.

Natural ventilation rates in bedrooms at night have been measured in retrofitted apartments. The measurements indicate clearly that air quality in bedrooms may be unacceptable in dwellings with an energy-efficient minimal ventilation rate. The air supply rates may be as low as 1 l/s/person in themedian case of bedroom size, ventilation rate and two occupants. The carbon dioxide concentration will reach a level of 4000-4500 ppm in the morning depending on the length of sleeping time in a closed room.

The performance of whole-house mechanical ventilation systems was explored in an full-scale indoor test house (volume 176 m³ ) . A range of parameters were monitored: * The pressure distribution * The inflow of outdoor air to each room, the mean age of air in each room and the air-exchange effectiveness * The spread of a 'contaminant' released respectively in the kitchen and in the bedroom. The tests were undertaken both with the internal doors closed and with the internal doors open. Both mechanical extract system and balanced (combined) systems were tested.