AIVC - Air Infiltration and Ventilation Centre

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air leakage

Final report ASHRAE Research Project 438-RP/ Evaluation of the techniques for the measurement of air leakage of building components.

Knowledge of the amount of air leaking into a building through the various building components is important for a wide variety of reasons. Initially the interest in these values was so that estimates could be made on the amount of energy to be added or removed to heat or cool air that was infiltrating into the structure. Selection of new and replacement building materials was done partially on the amount of energy costs that would be saved by the selection of that component.

Practical methods for improving estimates of natural ventilation rates.

This paper discusses four concepts that have been found useful in improving estimates of ventilation rates in residential buildings. These concepts are improved methods for describing leakage distribution and wind pressures: 1. Separation of large, well defined "local" leakage sites from the background building leakage. 2. Changing surface pressure coefficients to account for the effect of upwind obstacles. 3. Making wind pressures (in terms of pressure coefficient and wind shelter) continuous functions of wind direction. 4.

Measuring subfloor ventilation rates.

This paper reports on ventilation measurements taken beneath a suspended timber floor of a BRE/DoE energy and environment test house. Sulphur hexafluoride was introduced into the subfloor void at a constant rate and the resulting concentration measured. Wind speed, wind direction, and internal, external and subfloor temperatures were also recorded. A range of air brick locations were used for each run which lasted two to three days.