Describes the measurement of air change rate and airtightness of a mechanically ventilated public swimming bath in Belgium. The relationship between airtightness and air change rate is outlined. Various methods of calculating the air leakage from the pressurization results are compared. Nitrous oxide was used for the tracer gas measurements, which were made both with and without the mechanical ventilation system working. The LBL model was used to calculate the air infiltration rate.
Fan pressurization techniques are being employed by an increasingly large number of contractors and auditors to determine the leakage characteristics of structures. In this study, a large data base of flow exponents and flow coefficients are compiled to determine the degree of correlation that exists between flow parameters. The resulting empirical relationships are then used to determine the feasibility of predicting these flow parameters directly from a single pressure difference test. On the basis of these correlations, a new pressure independent tightness parameter is proposed.
Air leakage is the single most important quantity in the determination of air infiltration in residential structures. Air leakage is most commonly measured using the fan pressurization technique (ASTM standard E779): the data gathered with this method is often used to determine a leakage constant and a flow exponent. In this report, data gathered from measurements in the USA and Canada is compiled into a list of leakage constants and flow exponents, and the variability of these values over climate and housing types is examined.
An automated 10-point air sampling network which uses an electron capture detector gas chromatograph to continuously measure changes in sulfur hexafluoride tracer concentration in a residential environment will be described. The injection of the tracer is controlled by a microprocessor which decides to inject sulfur hexafluoride tracer to return its concentration to a preprogrammed set point. Infiltration rates from fan induced pressurization will be compared to the infiltration rates as reported from the replacement of sulfur hexafluoride tracer.
Evaluates results from constant concentration tracer gas measurements and fan pressurization measurements in three houses and predicts ventilation rates for longer time periods using the LBL model. Test results show that the best way of both supplying adequate ventilation and conserving energy is to make sure that the building envelope is sufficiently tight and then install a mechanical ventilation system. Shows that it is possible to correlate fan pressurization measurements and infiltration rates.
Describes a simple method to calculate the leakage area of a house regardless of design or weather conditions. The leakage area is used in the LBL infiltration model to calculate infiltration for any weather condition. This method, which uses fan pressurization to measure leakage area has been used in a survey of over 300 houses located through out North America. Presents the results of that survey and suggests that the present capability in air infiltration modelling offers an excellent framework for an air leakage standard for residential buildings.
Describes a field study carried out to evaluate the effectiveness of the air leakage sealing techniques employed by Ener-Corp Management Ltd. for reducing air infiltration in houses. Performs presealing and postsealing air leakage tests on 82 single detached houses, located in Winnipeg or southern Manitoba. The sample group consisted of 56 conventionally-constructed houses of varying size, style, occupancy and airtightness, and 26 nonstandard structures of smaller but identical size and age. This latter group was part of the Flora Place Project.
Studies the techniques and issues related to evaluating the airtightness of homes. The first section discusses the physics of air infiltration and the techniques used to measure infiltration rates. Also discusses pressurization testing and its relation to infiltration. The second section presents experimental work aimed at several questions raised in the first section. A long term experiment involving weekly pressurization testing of a home reveal the short-term reproducibility of the test results and the seasonal variation in a home's tightness.
A model that relates fan pressurization results to infiltration values during the heating season is the basis for infiltration estimates in several different audit programs. Describes the model and presents validation results. Uses the model in 3 different audit strategies. The first is an energy audit to determine economically optimal retrofits for residential buildings, based on actual, on-site measurements of key indices of the house. Analyses measurements on a micro-processor and determines retrofit combinations compatible with minimum life-cycle cost and occupant preferences.