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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 .

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.

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.

A Compact Equipment for Survey of Air Renewal (CESAR) was developed at the Ecole Polytechnique Federale de Lausanne in Switzerland. Controlled by a microcomputer, this apparatus uses tracer gas methods ( decay, continuous flow or constant concentration). Up to ten different locations in inhabited rooms can be monitored simultaneously over extended periods of time, using mainly the "constant concentration" technique. Several air renewal surveys were carried out on different inhabited buildings.

Describes a procedure for the approximate determination of air infiltration for a single family house for given weather conditions. To carry out the calculation it is only necessary to measure the permeability of the building envelope using a blower door. The calculation procedure is so straightforward that it can be carried out on a programmable pocket calculator. Refers to a comparative study by the Air Infiltration Centre, which found that the calculation model described gave the best results of any single cell model for all the houses investigated.

This study investigates the structure and availability of ventilation systems in domestic housing. A measurement programme of natural ventilation efficiency was carried out and evaluated. Mechanical ventilation systems were compared. Their suitability for efficient ventilation of various house types is discussed.

Discusses the findings of a nationwide radon survey carried out in W. German houses. The average radon concentration in 6000 houses is 40 Bqm/m3. Treats the incidence of radon in the environment, its sources, the consequences of inhalation of radon, physical processes in room air, and methods of radon measurement.

Reduction in air leakage rates due to weatherization of homes can be determined by fan pressurization and tracer gas techniques, but only the latter gives the results under normal occupancy conditions. Assessment of such rates measured before and after weatherization must consider their dependence on wind speeds and inside-outside temperature differences.

Facts and ideas are presented to improve cost effective designs for airtightness and ventilation systems. Schematically alternative measures to save energy are presented. An investigation of the rate of ventilation in 25occupied houses is described, using pressurization, tracer gas and measurements of air flow through exhaust air terminal devices. At a mechanical ventilation rate of 0.25 ach, the measured total ventilation rate averaged 0.29 ach (minimum 0.12 and maximum 0.50). Further results are given for 5 more recently constructed houses.