English

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.

Measurements of the dynamic heat transfer in a four-bedroom townhouse were made under controlled conditions in a large environmental chamber to explore the viability of a computer program developed at N.B.S. labelled NBSLD for predicting heating and cooling loads and inside temperatures. Test house was factory-produced, of modular design and lightweight (wood) construction. Tests were performed with simulated outside summer, winter and autumn diurnal temperature cycles. Inside temperature was maintained at 75 f and the activities of a six-member family were simulated.

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.

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.