Describes the extent of the problem of condensation in roof spaces of well-insulated dwellings, discusses the mechanisms resulting in condensation, and evaluates possible solutions. Factors considered in condensation occurrence include air movement to the roof space, and roof space ventilation rates. Control measures discussed include direct extract ventilation to the kitchen and bathroom to control water vapour, and the provision of adequate roof ventilation according to British Standard BS 5250.

The results of a prediction method for calculating ventilation rates in a detached house are compared with experimental measurements described in aprevious paper. The method is capable of giving good agreement for a wide range of ventilation conditions. The need is demonstrated for further work in two important areas - the spatial distribution of background areas and the effect of turbulence.

Briefly reviews the study of wind flow around buildings. Shows that fundamental theoretical and experimental studies are beginning to produce simple descriptive and mathematical models of flows round buildings. These should enable designers to predict the general features of wind around a proposed building or group of buildings at an early stage in the design. Gives some examples of these models.

Describes an investigation to see what energy saving can be achieved by the regulation of mechanical ventilation systems in high rise buildings. Measures air leakage in a block of flats, and uses a calculation model to predict the amount of energy lost due to ventilation in various situations. Concludes that the reduction of ventilation has no disadvantageous consequences for the operation of the system, and that the extracted air flow is affected more by incorrect adjustment of extractor vents then by opening windows, regardless of the setting of the ventilator.

States that one of the major difficulties in estimating air infiltration rates in buildings is lack of full scale data on pressure distribution on various structural shapes located in different types of surface roughness category. Tries to fill this gap by studying two building structures of different shapes and situated in different environments, registering the mean pressure distribution and calculating the rate of air leakage due to openings. The first house is of old type construction and in a `semi-urban' environment.

Many mechanically ventilated buildings are over-ventilated since ventilation rates are based on a fixed number of people (often in excess of the average occupancy) and no allowance is made for infiltration. States that the CO2 concentration in the ventilated space can be related to the ventilation rate per person, and by modulating the fresh air flow to maintain a constant CO2 concentration, a constant ventilation rate per person can be obtained.

Analyses an infiltration heat loss calculation in accordance with Standard CSN 06 0210, with regard to the minimum air exchange rate (0.3 ach/hr). Concludes that aeration through windows should be graded for buildings which are differently located in the landscape and thus differently exposed to the wind effect.

There are two types of air movement in the shell of a building - movement along the insulation as in cavity walls and movement through the insulation. Generally the heat losses due to the faults in the inner lining of the vapour barrier and the consequential air movement through the shell are much bigger then losses due to faults in the insulation - they cannot be compensated for by using tighter wind protection.

Describes the application of a model that relates infiltration to a quantity called the effective leakage area. This quantity scales the infiltration to local weather conditions and major design features of the house. The model isused to calculate the ratio of infiltration to leakage area averaged over the heating season, for a large number of sites in the US. It provides an effective tool for builders and designers who need a rational basis for assessing compliance with construction quality standards in ventilation.

Describes work sponsored by the Electric Power Research Institute (EPRI) to investigate indoor air quality in 10 single-family houses and 2 office buildings in Boston. The point was to compare indoor and outdoor pollutant levels, and find reasons for the differences. Found particulate levels were higher indoors, and houses with gas facilities showed higher concentrations of carbon monoxide and nitrogen oxides.