On the persistence of low wind speed conditions.

Light wind conditions are important in the assessment of risks from releases of hazardous gases, in the assessment of urban air quality, and also in the determination of ventilation requirements for buildings. Although very light winds would often prese

Code ventilation requirements.

The 1995 edition of the National Building Code of Canada has extensively changed the ventilation requirements for housing. The code includes detailed prescriptive requirements, because in the past ventilation system design and compliance has varied. In this piece we are focusing on the new requirements in the National Building Code. These requirements apply in all areas except for Ontario and B.C. where provincial requirements were modified several years ago, and will be continued with only minor modifications.

Outline of ventilation standard for acceptable indoor air quality, SHASE Japan.

The Ventilation Standard HASS-102 of The Society of Heating, Air-conditioning andSanitary Engineere of Japan (SHASE Japan) was revised in November, 1997. The title of therevised standard is Ventilation Standard for Acceptable Indoor Air Quality. So far, the oldVentilation Standard, which was issued in 1939, had been used for a long time. The task forrevision was undertaken by the Sub-committee on Ventilation Effectiveness and Standard(chaired by Murakami) of SHASE Japan.

Derivation of equations necessary for primary airflow redistribution in VAV systems to reduce outdoor air intake while meeting ventilation requirements.

The multiple spaces equation of ASHRAE Standard 62-1989 makes it possible to bring in a smaller fraction of outdoor air than that dictated by the critical space. This paper develops an analytical proof that increasing the primary airflow rate to t e critical space reduces the outdoor airflow rate required to meet ventilation requirements. For systems employing fan-powered boxes, where more than one box is critical, a systematic procedure for incrementally increasing the primary air is currently required.

The attribution of pollutant concentrations on buildings from local traffic - Effects on ventilation requirements - A Wind Tunnel Modelling Study

This paper describes an analysis using the BRE Pollution Dispersion Wind Tunnel to estimate pollution concentration patterns on buildings in urban arrays due to local line sources of pollution, typical of vehicular traffic emissions. The experimental procedure involved measurements of both pressure and concentration patterns on building forms in urban arrays, intended to provide information on the ingestion of pollutants into buildings in urban areas.

Ventilation requirements in non-domestic building and energy efficiency.

The research community as well as the design and construction practice is spending a lot of efforts and investments in developing systems which optimise the energy use for achieving certain specified air flow rates. For example, improvements in efficiencies of 10 % in heat recovery systems would be considered as remarkable. At present, one observes a tremendous difference in the ventilation requirements in various countries as well as at the European level.

Calculation of ventilation requirements in the case of intermittent pollution : application to enclosed parking garages.

The ventilation requirements for decontamination are normally determined with a static calculation method. In some cases, the pollutant emission is intermittent, for example in the car park of an office building, where all the cars enter and leave the place nearly at the same time. Generally, in such a case, the volume of the garage is large, consequently the time constant of the system has a high value. So a static approach would no longer stay accurate and a dynamic evaluation is needed.

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