English

This paper reports the findings from tests undertaken in an untight, two-storey, brick-built detached test house. Different ventilation schemes were in use: natural ventilation and mechanical ventilation (both extract and balanced ventilation).

A multicell air flow computer program is used to determine the influence of 1) open windows and 2) closed internal doors on the ventilation rate of a semi-detached house. The changes in interzone air movement and room air change rates are also examined. Tracer gas field measurements used to validate the multicell program show good agreement with the predicted values. Results show that opening windows can alter significantly, not only the overall ventilation rate of the building, but also the individual air change rates in rooms.

Describes the measurement of air change rate and airtightness of a mechanically ventilated public swimming bath in Belgium. The relationship between airtightness and air change rate is outlined. Various methods of calculating the air leakage from the pressurization results are compared. Nitrous oxide was used for the tracer gas measurements, which were made both with and without the mechanical ventilation system working. The LBL model was used to calculate the air infiltration rate.

This paper outlines the living conditions that can occur in the proximity of buildings and the significance of the wind velocities that can be established, for example for shopping centres when these include high-rise buildings or for patio schools when these are to be suitable for education in the open air. It also illustrates how natural ventilation in the building occurs and describes the influence of the wind on mechanical ventilation systems.

This report describes tracer gas measurements and pressurization tests made on two low-cost houses about one year after their construction. The influence of wind speed on the ventilation rate was found to be significant, whereas stack effect was found to have no significant influence. Infiltration rates of 0.24 and 0.34 h-1 were found. These values are very low for Belgian dwellings. A pressurization and depressurization test was performed for each house at pressure differences between 5 and 150 Pa. The ageing effect was found to be quite substantial.

Presents a detailed description of the measurement technique and apparatus used to measure the air change rate in the Spencer St and Linford low-energy houses in Milton Keynes, UK. An automatic air infiltration rig using nitrous oxide tracer gas constant decay was used. Air leakage was also measured by pressurization for the Linford houses and some from the neighbouring Pennyland project.

This paper presents a quantitative estimate of the error of the decay and constant concentration method. A number of tests were carried out in an indoor test house located in the laboratory hall at the National Swedish Institute for Building Research. The relevant meaning of the concept of air-exchange rate is discussed and an appropriate terminology is suggested. The theoretical background, based on a multi-cell model, of the two tracer gas methods is given.

This paper presents the results of a computational and experimental study to assess the possible benefits of using mathematical modeling techniques for cleanroom design. A two-dimensional modeling visualization has been used for each of the cases studied. This has the advantage that its relative cheapness allows more design variations to be analyzed than would be possible with a three-dimensional method. Full-scale measurements were also taken in the cleanroom which was the subject of the modeling exercise.

The determining parameters for the formation of condensation are 1) the surface temperature of the building section and 2) the dew point temperature of the air in the room. Thermal bridges in intensively insulated outside walls and decreased ventilation due to tighter windows both increase the risk of condensation. Mechanical ventilation reduces the risk, but natural ventilation is dependent on occupant behaviour.

Reduced ventilation and infiltration, and new materials and machines have increased levels of indoor contaminants. Investigations of many indoor environments reveal contaminant levels above those set as standards for the workplace environments. The acute and chronic health effects on the population are not well known. This paper discusses the current general status of the research in the USA and the planned future effort. Worldwide research is also summarized and future directions are suggested.