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Pubs, bars and restaurants are places where smoking policy is still left to the discretion of the manager and where smoking is often permitted. However, there is demand to take measures to eliminate or reduce the effects of environmental tobacco smoke (ETS) to non-smoking occupants. This paper reports the results of a field study in which ETS markers and air flow patterns were monitored in a number of occupied spaces. The measurements included CO concentrations as a marker of ETS, CO 2 concentrations as a general indoor air quality (IAQ) indicator and air flow measurements to estimate ventilation and infiltration rates. The findings indicate that shared-space smoking needs action beyond that of simple ventilation, segregation of occupants or simple partitioning to minimise the potentially harmful effects of ETS to both staff and customers.

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A major factor in the ventilation of buildings is the leakiness of the building envelope. In housing, it has been possible for some time to measure leakiness quickly and easily by using a fan (sealed in place of the front door) to pressure/depressurize the building. Until now, this has not been done in larger buildings either in the UK or elsewhere in Western Europe. The Building Research Establishment (BRE) designed and built three fan units which can be used together to pressurize large nonresidential buildings. A novel feature of the pressurization rig is that the fans are powered from conventional 13-A ring mains. This is in contrast to the techniques used in North America of either using a building's mechanical ventilation system (not possible in the UK since most buildings are naturally ventilated) or a large, bulky, trailer-towed fan with its own generator. Envelope leakage tests have been carried out in two medium-sized (approximately 5500 m3) office buildings. Pressure differences of well over the accepted target of 50 Pa between inside and outside were reached easily. Results showed that one of these buildings, of conventional construction, was twice as leaky as those found (on average) in North America. The other, built specifically as a low-energy office at BRE, was found to be as tight as the North American buildings. BRE will carry out measurements in further buildings as an aid to understanding and developing air leakage control from the viewpoint of natural ventilation.

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Sununary This paper describes field measurements to assess the effectiveness of trickle ventilators in providing adequate and controlled background ventilation in office buildings during the heating season. The tests were at full-scale in two multi-storey office buildings. Both are located within a built-up area and recently refurbished. Carbon dioxide, air ventilation rates, temperatures and relative humidity were monitored for two weeks in one open-plan office in both buildings. It was concluded that resultant internal airspeeds are low, thus minimising the possibility of cold draughts. Metabolic carbon dioxide levels are not excessive and adequate ventilation is provided. It was also found that occupants use trickle ventilators regularly to control their environment once they are familiar with their operation.

A preliminary study was carried out on a naturally ventilated office built as a low-energy building. The study uses a multi-zoned prediction program to determine a ventilation strategy to provide controlled background ventilation. Full-scale, whole-building pressurisation measurements are used to provide envelope leakage characteristics. The surface wind pressure coefficient data are provided through measurements carried out in the Building Research Establishment's Environmental Wind Tunnel. This study assessed the effectiveness of permanent but controllable background ventilators in naturally ventilated office-type buildings with various envelope tightnesses. Preliminary results show that, during the heating season, it is possible to provide adequate background ventilation for occupant comfort by incorporating commercially viable, manually controllable trickle ventilators within each room. Recommendations for possible consideration may be that 4000 mm2 open-area ventilators could be used in rooms with floor areas less than 10 m2, and 400 mm2 per m 2 (of floor areas) for those which are larger.