ON A SIMPLIFIED METHOD FOR MEASURING PASSIVE VENTILATION RATES

Recently most houses in northern Japan are highly insulated and air-tight, which can lead to seriousproblems such as indoor air pollution. It is important to evaluate the performance of an air-tight housefrom the viewpoint of ventilation. However, in general, houses consist of multiple rooms and each roomhas airflows in different directions which mix with each other. Therefore it is not easy to measure realventilation rates.The purpose of this paper is to evaluate a simplified method for measuring airflow rates in houseswhich have a basement with outer insulation. In such houses, where external air enters via anunderground pipe through the basement, the air is warmed. This airflow system is usually called apassive ventilation system, and inter-zonal airflows are measured with a technique using multiple tracergases. In this paper, a simplified method that uses a single tracer gas which is released at a constantrate is examined, and the usefulness of such a method to evaluate the passive ventilation system isdiscussed.