air tightness

A survey of twenty residential buildings was conducted to observe the impact of ventilation strategies on moisture· accumulation in attics. The objectives of the survey were to record attic lumber moisture content levels over a period of one year and to assess the ventilation characteristics of the attics in order to account for the recorded moisture levels. The sample homes represented a range of ages, construction types and attic venting formats. Five of the houses were located in a coastal climate. Two test protocols, developed specifically for this project. were applied to the sample.

There are many reasons why the air quality in a building may fall well short of what it was intended to be, explains Trevor Callen.

Building airtightness data are essential for design and model evaluation. An attempt has been made with the Numerical Database to compile data appropriate toinfiltration and ventilation studies. These cover the air leakage characteristics of building components, the characteristics of buildings themselves and data on wind pressure distributions. AIVC Technical Note 44 (Orme, Liddament, and Wilson 1994), contains detailed summary tables and graphs of the information stored in the computer Database, together with a complete list of references.

The purpose of this study was to test an Indoor Air Quality model on a variety of Canadian homes, and use this model to determine the optimal ventilation levels necessary to provide appropriate comfort levels. The Indoor Air Quality model tested (the AQ1 program), was a single zone hour-by-hour model of air leakage, mechanical ventilation and pollutant concentration. Measured weekly air change rates were compared to the model's predicted rates, and sensitivity analysis' performed on a number of inputs.

The ventilation of a Swedish single family house is investigated by means of tracer gas and pressurization techniques. The ventilation flow plays an important role in this house as it enters through a dynamic loft insulation and exits via the crawl space. This design is said to give preheated and clean supply air, warm floors and good energy efficiency. But to meet these promises, it is essential that the air really flows in the intended paths. A single tracer gas technique is used to determine the air flow rates.