English

Ventilation and air exchange in buildings and industrial plants can be induced by external winds and by buoyancy forces. The dependence of the air exchange and heat transfer on a large number of factors, including the detailed configuration of the building and surroundings makes an analytical or numerical analysis of practical design problems impractical, particularly when both the buoyancy and the wind-induced pressures are of the same order of magnitude.

The amount of air infiltration in a building, for given weather data, depends on the leakage and its distribution on the building envelope. In simulations of 17 designs of multiunit, multistorey buildings in Berlin, based on a typical meteorological year we obtained a wide range of infiltration values that varied according to the floor plan, the number and location of wall openings and cracks and the flow resistance relationship between the inside and the exterior of the building.

Air tightness results for 40 New Zealand timber frame houses of varying age and construction detail are given. The steady pressure method was used at 6-9 indoor-outdoor pressure differences in the range 10-150 Pa. The data is presented in four ways: 1. air changes per hour at 50 Pa, 2. the coefficient and exponent of a generalized leakage function, 3. the leakage rate per unit shell area at 50 Pa, and 4. the equivalent leakage area at 50 Pa. Houses in the 0-5 and 6-20 year age groups were not significantly different in terms of air tightness.

Dynamic insulation is a means of reducing building heat losses to near zero without the use of massive thermal insulation. It relies on recycling the heat conducted through the fabric or reducing the temperature gradient by means of a suitable heat transport fluid - usually air and sometimes water. Describes research and experience in Sweden and France. In Sweden, some 80,000 m2 of roofs (mostly of single storey sheeted structures) use the contraflow system of dynamic insulation and there have been a few experimental installations in the housing sector.

Presents the results of air leakage tests on the windows of the Arts Tower at Sheffield University. The results quoted show the ranges into which infiltration coefficients fall. Relates pay-back periods for weatherstripping to height above ground level. Tabulates mean values of leakage coefficient and flow exponent for defective and non-defective sealant and compares with values suggested in CIBS Guide.

Indoor air quality and air infiltration were measured in 16 low-energy Californian houses. Eleven houses had gas stoves: all had average infiltration rates of 0.5 h to the -1 or less, recent construction dates, low natural ventilation, and no mechanical ventilation.

Chemical pollutants and ventilation rate have been measured in newly built energy efficient private dwellings. The samples were taken in the absence of normal human activity in the houses. The data show that the main source of organic pollutants seems to be indoor building materials and furniture. For dust an important source could be the outdoor environment. Formaldehyde was primarily found in houses where chipboard was used while levels of radon daughters was very low in all houses tested.

With recent advances in technology, choices among measurement strategies for indoor air quality investigations have become increasingly complex. Design must weigh objectives and available technology against resources to implement the design. This paper provides a systematic framework for making proper choices among critical design alternatives. Design considerations include types of instrumentation, location of probes, and number and frequency of measurements. Examples drawn from case studies will be presented to illustrate these considerations.

Indoor pollutant levels in well-insulated houses are being investigated in a 2-year theoretical and experimental study involving the simultaneous measurement of meteorological variables, air exchange and circulation, and energy consumption. This paper describes concentrations of radon, radon progeny, formaldehyde, carbon monoxide, and nitrogen oxides observed in two houses over two seasons, summer and fall 1983. Two companion papers provide a perspective on the problem and the study design, and present results of energy use and infiltration measurements.

A tracer gas technique has been used for evaluation and characterization of air flow pattern of contaminants penetrating into buildings. As a tracer, sulfur hexafluoride (SF6) was used and detected by a gas chromatograph equipped with an electron capture detector. SF6 was released at suspected points of contaminants origin at a constant flow rate and was detected quantitatively in the room or laboratory of concern.