air infiltration

States that the calculation of transient pressures in buildings requires the estimation of the rate of air leakage through various paths. Gives an expression for infiltration through a wall component. Gives formulae for calculating pressure transients inside a building under forced ventilation with air leaking out of the building under various conditions. Theseformulae also apply when air is leaking into the building. Discusses practical applications and the practical problems for which the formulae are useful.

Describes continuous measurements of wind induced pressure differences across the exterior walls of two schools taken over a period of 8 months. These schools were selected from a total of eleven schools whose air leakage characteristics had been previously studied. Calculates air infiltration rates caused by wind using the measured differentials. Evaluates equivalent pressure differentials caused by wind. Calculates uniform pressure differentials caused by stack action using a computer model.

Describes computer program used to calculate air flows and pressure differential in a building as a result of a combination of wind effect, stack action and the operation of air handling systems. Describes mathematical model of building and the assumptions and limitations of program. Gives listing of complete program.

The use in metropolitan cities of increasing numbers of skyscrapers in which stack effects are large and entrance traffic heavy calls for a better design of entrance for controlling both infiltration and traffic. Analyses the causes of infiltration, discusses the effect of various parameters, presents design charts for estimating heating and air conditioning loads through swinging-door and revolving-door entrances. Introduces a new design of entrance, the travelling entrance-way, and gives approximate method for calculation of air infiltration through it.

Reports tests made on a mobile home to evaluate its thermal performance. Describes home, instrumentation and test procedure. Gives energy consumption as a function of indoor-outdoor temperature difference. Finds that oversized heating plant resulted in low seasonal operating efficiency. Air infiltration was measured using pressurization technique and SF6 as a tracer gas. The latter showed that operation of the heating plant induced higher air infiltration rates. Reports thermographic survey of interior surfaces which showed air paths formed by wrinkles in the surface insulation.

Describes computer program used to calculate the air flows and pressure differentials in a multi-storey building as a result of a combination of wind effect, stack effect and the operation of air handling systems. Describes mathematical model of building and assumptions and limitations of program. Gives complete listing of program.

Describes a general model for air infiltration which will accomodate wind pressures, stack effect and ventilation openings provided the vents are either all above or all below their respective neutral pressure levels. States that main innovation of this model is expressing the infiltration as a function of the shell leakage and of the neutral heights of each face.Describes experimental method for finding the neutral pressure level. Gives typical values of parameters for tight mid-westhouses for light and strong wind.

Outlines a number of experimental approaches for determining the energy consumption of a building, with emphasis on air infiltration. The combined use of depressurization of the house and infrared scan permits the location of "bypass" vents through which warm air is leaving the structure. Describes several types of bypasses and evidence for their widespread existance is documented. Discusses the side effects of retrofitting these and other energy loss sites with regard to fire safety, air quality and moisture.

Gives theoretical justification for the use of tracer gas method for measuring air infiltration. Describes automated instrumentation system using sulphur hexafluoride as a tracer gas. The system consists of an electron capture detector, an automation unit, an SF6 storage and injection panel, a cassette recorder and corresponding plumbing and tanks. Gives examples of field use of system.

Describes a system which measures the rate of air infiltration in buildings using sulphur hexafluoride as a tracer gas. Discusses two methods for evaluating the infiltration rate,the decay method and the constant concentration method. The system automatically operates a portable electron capture detector /chromatograph and samples air on a one-minute cycle. In the decay method the slope of concentration vs time on a semilogarithmic plot can be used to compute infiltration rate.