Discusses radon risks in housing and carcinogenic effects. Compares background radiation as part of our natural environment and the effects of radon gas on building materials. Notes effects of reduced ventilation designed to reduce energy consumption and its influence on the frequency of cancer.
Describes a simple method to calculate the leakage area of a house regardless of design or weather conditions. The leakage area is used in the LBL infiltration model to calculate infiltration for any weather condition. This method, which uses fan pressurization to measure leakage area has been used in a survey of over 300 houses located through out North America. Presents the results of that survey and suggests that the present capability in air infiltration modelling offers an excellent framework for an air leakage standard for residential buildings.
Conducts tests over a period of 18 months in a house near Knoxville Tennessee to determine the effect of forced ventilation on the infiltration rate. Uses an outside-vented electric dryer as the power vent. Carries out testing during a variety of weather conditions. Uses SF6 as a tracer gas to measure infiltration rates. Develops a non-linear regression based on measured data relating the change in house infiltration rate to the vent rate.
To experimentally determine the repeatability of pressurization test results, pressure tests a home about 80 times in one year. Studies the effect of weather conditions on test results, along with changes in the results over time. For local wind speeds less than 2.5 m/s the 50 Pa leakage rate has a standard deviation of about 2% of the mean over short time periods. For stronger winds, errors as large as 15% compared to calm weather test results occur. Finds a seasonal variation of 25% in the leakiness of the house.
Presents data on the air infiltration and ventilation rates in 2 large commercial buildings. One building is a 4 storey, 10000m2 office building near Glasgow, Scotland; the other is a 26 storey, 100,000m2 skyscraper in Newark NJ. Collects the data on air infiltration and ventilation rates by a micro-computer based automated air infiltration system which controls the injection of a tracer gas into the various zones of the building and monitors its decay.
Reviews the present state of knowledge of indoor pollutant concentrations, their time dependence and their relationship with indoor sources, energy conserving measures and indoor activity patterns. Pollutants of primary concern are organic compounds, respirable suspended particulates, nitrogen dioxide and allergens. Assesses knowledge of carbon monoxide, formaldehyde, radon and infectious agents. Reviews typical concentrations of carbon monoxide, asbestos, mineral fibres, ozone and sulphur dioxide in residences. Concludes that a systematic assessment of indoor air quality is warranted.
Characterizes indoor contaminants as two continua - mass stressors and energy stressors. Describes the rates of generation and transportation of contaminants in terms of 4 sources (outdoor air, building materials, occupants and indoor processes) in 4 environmental zones. Reviews information on contaminant generation and discusses factors that affect these rates, including temperature, moisture content, acidity, room air distribution and occupant proximity. Concludes that sufficient information is available for new control strategies to be used to provide acceptable indoor air quality.
Examines what adequate ventilation rates are needed to control indoor levels of formaldehyde. Concludes that the ventilation rate procedure of ASHRAE Standard 62-1981 "Ventilation for Acceptable Indoor Air Quality" offers protection from expected formaldehyde outgassing rates. Since formaldehyde outgassing decreases with time, increased ventilation during the first 2-3 years of the life of a structure is desirable. More data is needed to establish what the outgassing rates are and how they vary with temperature.
Presents results from an investigation of the effects of different structural and mechanical energy conservation measures in swedish houses. Selects at random houses whose owners have received government grants for energy conserving measures. Compares actual and theoretical savings in the houses forvarious structural modifications. Discusses reasons for variations in savings between houses with the same modifications. Includes a description of thecalculations used to determine savings.
When wind and mechanical ventilation effects work together simultaneously, the combined effects of the two cannot be given by simple linear summation. Investigates this non-linearity of pressure differentials by the wind tunnel test of a model building, and verifies its effect on air infiltration.
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