Summarizes the state of knowledge about combustion products, surface condensation and mould, formaldehyde and radon, and the guidance currently offered on their control in the UK. Statutory ventilation requirements are outlined and various measurement techniques described.

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.

Most houses in the Netherlands are equipped with gas-fired heaters and cooking appliances, since large amounts of natural gas are available. Carbon monoxide poisonings occasionally occur due to the use of instantaneous water heaters (geisers) that are gas fired. An investigation was carried out to establish the carbon monoxide production potential of geisers under normal conditions of use. The study involved 254 houses: the results indicated that 17% of the geisers produced a carbon monoxide level of more than 50 microL/L in thekitchens where they were located, after 15 min of operation.

The influence of the various sources of pollution on the home environment in the Netherlands is reviewed, eg, outdoor air, gas-fired appliances, tobacco smoking and building materials. The pollutants carbon monoxide, nitrogen dioxide, particles and radon are discussed in more detail. Available data show that outdoor standards for air quality are often exceeded indoors. However, conclusions on exposure and health effects cannot be drawn until more data are available from random or stratified samples of houses.

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 reviews the work carried out in the Netherlands on moisture problems. In current air flow simulation models for buildings, moisture transfer and diffusion in and between rooms are not taken into account. The aim of the research project is the development of an integral hygrothermal model in which the above mentioned aspects are incorporated.

Over the last few years frequent cases of mould growth in dwellings have occurred. The problem is essentially due to an excessive moisture content of the building elements, which can result from hygroscopic adsorption or from frequent surface condensation.

Surface condensation and mould affect about 15% of the UK housing stock. This paper reports BRE work undertaken in occupied dwellings to identify the effectiveness of a range of remedial measures in various situations. The remedies investigated include the improvements to insulation levels, andheating systems, the provision of extract fans and dehumidifiers. The studies were undertaken in both flats and 2-storey houses, all of traditional construction with brick walls and pitched roofs.

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.

Outlines some of the principles behind air driven aspects of moisture in buildings and illustrates how calculation methods and mathematical modelling techniques may be used to both predict and remedy associated problems. Primary remedies include a reduction in the generation of moisture, ensuring thermal integrity of the building and providing adequate ventilation. The use of dehumidification may also have a role to play. Mathematical models offer an inexpensive method for assessing design ideas at an early stage of development.