Shows that the interior pressures in buildings are amenable to more detailed analysis than is conventionally given them and that useful information on them can be easily derived from the wind tunnel data on external pressures. The uncertainties can be expressed in parallel statistical terms. The importance of fluctuating pressures are related to the area of the opening and interior volume and a simple criterion indicates when these are likely to be important.
Discusses the advantages of reducing air infiltration in industrial buildings in terms of energy conservation. States that heat loss due to infiltration is often underestimated or ignored as it is difficult to measure. Concentrates ondoorways as a major source of infiltration, and shows that the type of door used needs to match the requirements of the entrance, such as type and size of vehicle passing etc. Decribes a range of doors suitable for different conditions.
States that methods used by Swiss energy consultants in calculating air change rates are often inaccurate. Most consultants use the "observation method" utilising smoke pencils etc. and mistakes are made in calculating conditions causing air infiltration. Describes a new graphic method for estimating mean air change rates, which needs data on construction, pressurization values and window opening.
Reviews air infiltration studies in New Zealand. Tighter houses have evolved over the years through changes in building methods and materials. Some of the tighter houses can have condensation problems. Investigates the airtightness of 40 houses together with the leakage resistances of a range of building components and bulk sheathing materials. A comparison with houses in other countries shows that comparatively tight houses can arise from simple construction methods not employing vapour barriers. Gives air infiltration rates as a function of windspeed for 4 of the 40 houses.
Describes the testing of 8 federal office buildings (size from 3000 sq.m. - 45000 sq.m.) for their air infiltration characteristics, as part of the NBS program to develop diagnostic test methods for evaluating the thermal integrity of federal office buildings. Performs tracer gas tests in the autumn, winter and spring to evaluate both the ventilation of these buildings during occupied periods and the natural air leakage under various weather conditions.
During winter experiments in central Pennsylvania a windbreak, 61 metres long and composed of a single row of white pine trees, significantly reduced air infiltration rates and space heating energy needs in a small mobile home by upto 54% and 18% respectively. Greatest reductions in air infiltration rates occurred with the home at one windbreak height (1H) downwind, even though maximum reductions in wind velocity occurred at 2H or 4H downwind. Space heating energy savings were less sensitive to downwind position, with maximum energy savings measured at both 1H and 2H.
Reviews the mechanism of air infiltration as a background for introducing a procedure that yields more reliable estimates of average infiltration rates through a window unit than do methods currently employed.The procedure is applied to estimating the average winter heat losses through windows in low-rise residential buildings variously located through out the US. Concludes that, regardless of climate, the heat loss attributable to infiltration through the window unit is small compared with that incurred as a result of direct transmission of heat through the window.
Discusses MEPA (Microcomputer Energy Programs for Architects) which has been developed in Sweden to supply energy analysis information during the early stages of design of residential and small commercial buildings, and is used inSweden, Kuwait and the US. It is designed especially for architects using microcomputers.
Studies the airtightness of about 50 passive solar homes located through out the USA using low cost measurement techniques. Measures include pressurization tests to measure airtightness and tracer gas measurements to determine air infiltration rates. Pressure tests show a variation in airtightness of homes from 3-30 changes/hr at 50 Pa, with a median of 5-9 changes/hr.The air infiltration measurements cover a wide range from 0.05-3 changes/hr, with a median of 0.5 changes/hr. Finds that these passive solar homes are not significantly tighter than less energy-conscious houses.
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