pressurization

Describes pressure method for testing whole houses for air leakage. States main advantages compared to tracer gas technique are that equipment is inexpensive, easy to handle and so well adapted to routine tests. The house is pressurized using a powerful fan and the flow through the fan is equivalent to the leakage through the building envelope at given pressure. Summarizes measurements made on test houses. and shows use of thermography to detect leaks. suggests use of pressure test to estimate the natural ventilation of a house.

Describes portable air leakage apparatus capable of measuring the air infiltration of whole dwellings directly on site by the pressure method. Main assembly consists of a flow measurement duct and electric fan. Describes test procedure and gives air leakage curves for an ordinary semi-detached house and an experimental house. Finds that doors and windows account for a surprisingly small proportion of total leakage.

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.

When attempting to determine heating/cooling requirement of a home a difference in infiltration can drastically affect heating/cooling requirement imposed on air conditioning system. Describes "the super sucker" machine designed to depressurise homes so that infiltration can be measured under simulated windconditions and each area of leakage isolated. Illustrates machine photographically. Gives method of determining air change rates. Summarises test data for several homes which indicatethat infiltration could be effectively reduced by use of various caulking compounds.

Outlines parameters governing air infiltration. Discusses problem areas of house to house comparisons of air leakage. Deals primarily with tracer gas procedure as compared with pressurisation/depressurisation approach. Describes testing in townhouses of recent construction as well as in a number of older homes of varied design. Uses roof-top laboratory test chamber to examine relations between wind effects, buoyancy effects and building openings and how they effect air infiltration. Uses results to clarify evaluation of air infiltration.

Reports pressurization tests on eleven schools both with the air handling system on and with it off. Obtains air leakage through components of the building by comparing overall leakage rates before and after sealing each component. Uses leakage rates to calculate air infiltration using a simplified model of a school building. Finds that infiltration caused by stack effect is significant even for a single-storey building.

Describes measurements of airtightness and ventilation in prefabricated 'modulent' houses, 25 single-storey with habitable lofts and 8 single-storey, all with mechanical extract systems. Measurements used pressure method and tracer gas in houses with different airtightness, types of window, windproofing and facing materials. Possibility of presetting ventilation terminals and fans to achieve recommended airflows was investigated. Treatsrelationship between wind, temperature and airtightness. Notes number of shortcomings in ventilation system discovered during investigation.

Describes experimental method of determining air leakage characteristics of exterior walls of a building. Method involves pressurising the building with the supply air system and measuring flow rates of outside supply air and resultant pressure differentials across building enclosure. Uses results to obtain flow coefficient and exponent for exterior walls. Checks method by results of computer simulation of a building, finding good agreement.

Reports results of series of tests on 6 single-family houses to determine rates of overall leakage through windows, doors, walls and ceilings. Uses vane- axial fan to reduce pressures inside house and measure flowrate and resultant pressure differences across house enclosure. Purpose of tests was to assist in eliminating rates of air infiltration in houses.

Summarises results of research project comprising survey of air tightness and natural air change rates in various types of residential building. Briefly describes equipment for pressurization tests and tracer gas measurements. Compares properties, range of measurement and cost of 5 different tracer gases. Provides some results from measurements in 53 single family houses and 28 flats. 9 of tested dwellings had their tightness improved and supplementary measurements made.