Gives general account of Twin Rivers project summarising main findings from 1972 to date. Includes section on air infiltration. Measurements of infiltration rates were taken using tracer gas method and regression equation found for the data.

Details the retrofits at Twin Rivers, grouped into packages A,B, C and D. A,B and D reduced heat flow through attic and basement. B limits the amount of air infiltration from crack openings, especially round windows and doors, by the addition of Vinyl foam weatherstrips, caulking of window and door frames and adjustment of ill-fitting casements.

The measurement systems used at Twin Rivers for determining energy usage are described. These include a weather station, three different systems for the measurement of temperatures and energy-related events in a house, a tracer-gas based air infiltration measurement system and infrared thermography

Notes heat flow through double windows due to temperature difference and air infiltration have usually been calculated separately. Tests combined effect of air pressure and temperature difference on three double hung prime windows in combination with various storm windows. Found that calculation of infiltration and transmission losses separately gives higher heating requirements than necessary and that air leakage increases with temperature differential. An overall heat transfer coefficient is determined

Presents a review of the problem area relating to unintentional ventilation, with special reference to the significance of this phenomenon with regard to the heat balance of buildings. It also contains a list of research tasks which the authors consider to be urgent. Factors which affect unintentional ventilation are discussed, such as wind and temperature conditions outdoors, permeability of the climate envelope of buildings, flow conditions on rooms with known rates of air supply and known temperature conditions, air movements in a flat and in the entire building.

Gives the results of measurements of wind and driving rain carried out over a 1-year period on an 18-storey block of flats, and compares these results with calculated and model scale data. The in-situ measurements indicate that the pressure differences between various locations on a facade, exposed to rain are much smaller than the calculated values, and also pressure differences due to wind at a window between the inside and outside are much lower than the theoretical values.

Describes apparatus used to measure air leakage through walls, the types of walls and the test procedure. Gives results of tests on plain walls and shows the effect of adding plaster and paint. Concludes that infiltration rates of plain walls vary greatly. Of the three factors, affecting infiltration rates, workmanship is the most important, the composition of mortar next and the type of brick the least important. Finds that gypsum plaster stops almost all infiltration and that the application of paint reduces leakage.

States that it is usual to assume a certain pressure difference across a window for a given wind velocity. Describes method of recording and instrumentation used to record wind speed and direction and pressure difference across two windows. Gives results of measurements showing dependence of pressure on winddirection. Shows that stack effect, even in buildings of moderate height, may be of sufficient importance to require a different allotment of heating capacity between lower and upper floors.

Notes that reduced infiltration and ventilation rates in buildings can lead to higher levels of indoor air pollution. Discusses three indoor-generated pollutants : nitrogen dioxide, formaldehyde and radon. Suggest ways of circumventing increased health risks without compromising energy conservation considerations, including setting standards for minimum levels, filtering recirculated air and sealing source material.

Presents description of an automated, controlled-flow air infiltration measurement system. This system measures total air flow, a volume per unit time, due to infiltration in a test space. Data analysis is discussed and the mixing problem analysed. Different modes of operating the system are considered : (1) concentration decay, (2) continuous flow in a single chamber and (3) continuous flow in a multichamber enclosure. Problems associated with the use of nitrous oxide as a tracer gas are described.