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air leakage

A duct performance model that includes the effects of leakage

A model for air flow inside ducts with leakages has been established from the equations governing the variation of total pressure and velocity along the duct. It was found that duct performance could be expressed as a function of two dimensionless constants, allowing the calculation of the required total pressure and velocity in the duct.

Development of pressurization airflow design criteria for spaces under required pressure differentials

This paper establishes the relationship between space pressurization ratio and air leakage flow through irregular cracks or through an open door . A numerical approach shows that room pressurization ratio can be estimated from room effective leakage area and from the pressure difference across the room shell.

Field measurement of the airtightness and delivery effectiveness of HVAC duct systems.

This paper presents the results of a field study on five HVAC duct systems in France. The principal objectives of this work were a) to evaluate the extent of duct leakage in those systems; b) to compare design and actual fan flow rates; c) to evaluate the thermal energy losses in the air ducts. The ductwork airtightness, measured by fan pressurisation method, was found to be in general well above the leakiest EUROVENT 2/2 class (class A), yielding unacceptable uncontrolled airflows. Fan airflow rates were measured with the constant injection tracer gas method.

A proposed test procedure for separating exterior envelope air leakage from interior partition air leakage.

Describes a new airtightness test procedure for testing a single zone within a multizone building. The technique enables the measurement of partition leakage so that it can be subtracted from the overall zone leakage.

Is there a new IR camera in your future?

States that the introduction of focal plane array (FPA) products in infrared thermography in the 1990s dramatically improved quality and has helped to lower prices and that infrared thermography has long been used for building diagnostics because there is no better way to see otherwise invisible problems related to insulation performance or air leakage.

The impact of added insulation on air leakage.

Short article on insulation for residential buildings.

Measured pressure equalized performance of an exterior insulation finish system (EIFS) specimen.

Describes a research and development project that has been started in order to generate design guidelines for PER walls. The three tasks covered are computer modelling, experimental evaluation and development of design guidelines. Describes the results of the experimental evaluation of an exterior insulation finish system. The systems were evaluated for air leakage characteristics, pressure equalization response and water penetration. Concludes that a wall designed to PER principles is more able to resist rain penetration.

Airtightness of 12 non residential large buildings. Results from field measurement studies.

We investigate the airtightness of 12 French non-residential buildings, by means of experimental fan-depressurization tests. For this study, 12 recent large (volume > 500 m 3 ) buildings have been chosen according to the construction structure and the activity. Four categories of buildings have been selected : hotels, schools, offices and polyvalent halls. We assessed the air leakage rate of each building, with a fan-depressurization equipment, following the recommendations of the international norm project ISO 9972.

Air leakage characteristics, test methods and specifications for large buildings.

A literature survey was conducted to identify measured airtightness values for various types of large buildings including Multi-Unit Residential Buildings (MURBs); offices; schools; commercial, industrial and institutional structures. Data was identified for 192 buildings in Canada, the United States, Great Britain and Sweden.

A predictive method to determine the leakage area needed in residences for IAQ control by infiltration.

A technique has been developed to estimate the equivalent leakage area needed in residences to provide a quantity of infiltration-driven air exchange which exceeds a design value for a desired level of frequency of occurrence. The technique presented applied an air infiltration simulation model to hourly long term weather data to provide hourly estimates of the infiltration weather factor. Cumulative frequency distributions (CFD) were then used to describe the distribution of these data when 1-, 3-, 6-, 8-,12-, 24-, and 48-hour time periods were grouped together.

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