English

Describes how ventilation rates in two houses with recirculating air distribution systems were monitored by injecting CO2 tracer gas into the supply and measuring its concentration in the return air. In one house with solid concrete floor, normal windows and air bricks, ventilation rates were mainly dependent on wind speed. In the other with suspended timber floor and weatherstripped windows ventilation rates were much lower and mainly dependent on internal to external temperature difference.

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

Developes mathematical model of air infiltration based on crack flow equations. Describes measurements made on test house. Shows that actual pressure distributions in walls deviate considerably from values in guidebooks. Finds background leakage area of house by pressurizing house with electric fan and measuring pressures. Suggests two distributions for leakage areas. Measures infiltration rate using helium tracer gas, recording temperature and pressure differences. Concludes that comparison between prediction and experimental results is encouraging.

Gives results of measurements of air-change rates and heat loss in occupied and unoccupied houses on two sites, one exposed and the other sheltered. Observations of the wind pressures on the houses and of the window-opening habit of the occupants are discussed. These are used in conjunction with the results of a regional survey of the temperatures maintained and the window-opening habits in local authority houses to extend the application of the results of other housing.

Reports measurements made of wind pressures on a multi-storey building in London. Autocorrelations and power spectra were computed for the 48 pressure transducers and showed noticeable fluctuations in the pressures on the windward face, Possibly caused by a cushioning effect in front of the building "leaking" away at regular intervals. Mentions effect of the permeability of building. Comparisons made with wind tunnel tests improved when surrounding buildings were taken into account. Recommends design gust durations for various sizes of building.

Reports wind tunnel tests made on model building. Wind pressures on the models were measured using several manometers in holes on the windward side and a single manometer on the leeward side atwind speeds of approximately 35 feet and 45 feet per second. Single models and single models with a shielding building at varying distances were tested, and pressure distribution found.Comparison with full-scale tests indicates the general form of pressure distribution is the same but pressure reduction on leeward side is greater in full-scale test.

Describes the determination of infiltration rates for houses in Seneffe. Gives infiltration rates for individual rooms, found using O2 as tracer gas, and recording wind speed and direction. Determines global air renewal rate using N2O as tracer gas, by injecting gas through ventilators into all rooms and measuring concentration in each room. Calculates global concentration from individual measurements.