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air leakage

Weather resistive barriers : new methodology for their evaluation

Effective weather resistive barriers (WRB) perform important functions in retarding waterentry into walls and in controlling water vapor movement as well as the amount of energyattributed to air leakage (Burnett, 2000; Weston et al 2001). Recognizing this, a public andprivate sector research consortium was established to develop reliable and precise methodsfor evaluating their performance.This paper, third in a series, provides an overview of the most significant results obtainedduring the consortium work.

Duct leakage in new Washington state residences : findings and conclusions

Many energy codes require that ductwork installed outside of the conditioned space be sealed. Prescriptive codes have no performance standard for what constitutes an acceptable level of duct sealing. Testing and anecdotal evidence indicate that many new homes have extensive leaks on both the supply and return sides of the heating system. A field study of 29 recently built homes was conducted in the Spokane, Washington, area. Systems were visually inspected; all defects were

Leakage of ducted air terminal connections : part 2, experimental esults

Leakage data for ducted air terminal connections are reported. The leakage flow rate generally varied from 1% to 8% of the total approach flow rate. Leakage was found to increase with the increase in the static pressure adjacent to the terminal for the unsealed condition. With marginal sealing of rigid ducts, leakage was found to be less than half that of the unsealed connection. The use of drawbands to mount air terminals to flexible ducts can reduce leakage at the collar to virtually

Leakage of ducted air terminal connections : part 1, experimental procedure and data reduction

An experimental study was conducted to estimate the leakage through air terminal connections to rigid duct and flexible duct. Air terminals from three different manufacturers were tested under different sealing conditions, namely, unsealed, marginally sealed, and fully sealed. Diffusers and supply grilles were tested in a blow-through test setup, whereas return grilles were tested in a draw-through test setup. The experimental procedure and data reduction are described.

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.