A condition often assumed when designing a naturally ventilated building is where air enters at low level and leaves at high level due to the stack effect. It then follows that, at upper levels, the air may be relatively 'stale' since it has previously passed through the lower storeys. An analogous situation may arise when wind is blowing, in which the air entering through the windward face becomes stale as it passes through the building to the downwind sections. It is not well understood how ventilation may, in reality, be affected by this.
An investigation was conducted of the effect of decreasing the air leakage area across internal partitions of a typical modern high-rise apartment. The objective of this work was to study the practicality of increased compartmentalization or separation of the living units from each other and from the corridors and vertical shafts in the building. Typically, the main barrier to air movement through a high-rise apartment building is the exterior skin or envelope.
A study was set up to compare the effectiveness of passive stack ventilators (PSV) with mechanical extract fans (MEF) in providing adequate ventilation in UK homes. New build and refurbished homes with PSV and MEF were identified and questionnaires posted to 3000 households of which 1223 were returned. The survey showed that in homes installed with a PSV system, only 7% of those in the kitchen and only 8% of those in the bathroom were reported as blocked up. There were also few cases in which the MEF was blocked up or disconnected: 1.5% in kitchens and about 5% in bathrooms.
Almost 60% of French residential buildings were built before the seventies, and an important part of those is to be retrofitted for complying with new needs with regard to acoustic insulation and energy saving. Retrofitting modifies the airtightness of the building envelope and can lead to an insufficient air change rate in passive stack ventilated buildings ; the existing ventilation system has therefore to be redesigned in order to insure adequate indoor air quality.
The paper presents the results of a simulation study performed by means of the COMIS multizone infiltration and ventilation model. The simulations were carried out for a two-storey single-family passive-stack-ventilated house in a cold climate (Stockholm, Sweden). Main conclusions of the study include the following: it is possible - during at least 75 % of the heating season - to achieve a ventilation rate in the whole house of at least 0.5 ach or approx. 30 l/s only if the house has a leakage rate above approx.
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