Ventilation measurements in large office buildings.

Ventilation rates were measured in nine office buildings using an automated tracer gas measuring system. The buildings range in size from a two-storey federal building with a floor area of about 20,000 ft2 (1900 m2) to a 26-storey office building with a floor area of 700,000 ft2 (65,000 m2). The ventilation rates were measured for about 100 hours in each building over a range of weather conditions. The results are presented and examined for variation with time and weather. In most cases, the ventilation rate of a building is similar for hot and cold weather. In mild weather, outdoor air is used tocool the building and the ventilation rate increases. In the buildings where infiltration is a significant portion of the total ventilation rate, this total rate exhibits a dependence on weather conditions. The measured ventilation rates are discussed in relation to the outdoor air intake strategy in each building. The ventilation rates are also compared to design rates in the buildings and ventilation rates based on ASHRAE Standard 62-81. Some of the buildings are at times operated at lower ventilation rates than recommended in Standard 62-81.