The current German Standard specifies a minimum thermal insulation. However even with excellent insulation, if the air change rate is too low, condensation can form. High humidity emissions in dwellings can require air change rates of more than 2/hour. The use of mechanical ventilation, possibly humidity-controlled and with a heat recovery system, is suggested to minimize ventilation heat losses. The user has to be educated to provide adequate ventilation in spring and autumn, but during the cold season the ventilation rate can be reduced to two thirds of the minimum value.
This paper examines the frequency distribution of indoor radon concentrations and air exchange rates in conventional and energy-efficient houses, discusses radon source magnitudes, compares the distribution of source magnitudes with information on emanation rates from source materials, and, finally, considers the ways in which variability in source magnitude might affect regulatory efforts to control indoor concentrations of radon and its daughters.
Carbon monoxide and nitrogen dioxide were monitored in 12 homes on a real-time basis to determine their transient concentrations, their dispersion through the homes and day-to-day variation in pollutant levels. Kitchen ventilation was determined using sulphur hexafluoride tracer gas, and use of unvented gas appliances was monitored with thermo couples. A week-long measurement programme was undertaken in a wide range of homes to determine the distribution of carbon monoxide, nitrogen dioxide, particulates and organic compounds.
Final report on the performance of 177 low-energy houses at Pennyland, Milton Keynes, UK. Pressurization tests showed an air change rate of 0.3 ach for the Pennyland houses, compared to 0.7 ach for the control Neath Hill houses. Three quarters of the houses had some condensation and over a half had some mould growth.
The Alberta Home Heating Facility has been used over a five year period to attempt to understand the effects of retrofit procedures on the house structure as a whole. The percentage of total energy attributable toinfiltration is calculated, and the influence of furnaces on natural infiltration rates is discussed. Results of blower tests are given for the six modules and compared with measured infiltration rates.
Sixty houses built with widely different construction practices and located in different areas in upstate New York were monitored for airtightness (using fan pressurization) and integrated radon concentrations in indoor air, household water,
Wind tunnel tests were carried out using models of fallout shelters to determine correlations between shelter ventilation rate, area and distribution of wall openings, and wind speed and its direction relative to the orientation of the shelter. Models of bermed shelters with five different opening configurations were used in these tests. A simple correlation was formulated between the shelter ventilation rate, the total area of windward openings, the ratio of leeward to windward opening areas, and the velocity of the approach wind.
Twelve energy-efficient houses in Eugene, Oregon, USA, were measured for effective leakage area using blower door fan pressurization. Air exchange rates over a period of several hours were determined by tracer gas decay analysis.
Air exchange rates were measured in the National Archives Building under various combinations of temperature and wind speed. The average air exchange rate under normal operation of the HVAC system was 0.9 h-1 for an average temperature difference.
This paper describes the procedures used in residences for rapid grab-sample and time-dependent measurements of the air-exchange rate and radon concentration: the radon source magnitude is calculated from the results of simultaneous measurements of these parameters. Grab-sample measurements in three survey groups comprising 101 US houses showed the radon source magnitude to vary approximately log-normally with a geometric mean of 0.37 and a range of 0.01 to 6.0 pCi/l/h.
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