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This paper reports on ventilation measurements taken beneath a suspended timber floor of a BRE/DoE energy and environment test house. Sulphur hexafluoride was introduced into the subfloor void at a constant rate and the resulting concentration measured. Wind speed, wind direction, and internal, external and subfloor temperatures were also recorded. A range of air brick locations were used for each run which lasted two to three days.

Experimental U-values based on measured heat flows through the walls of some houses have been found to be significantly higher than predicted by conventional calculation procedures. The work was carried out in ordinary occupied houses, and included measurements on party, internal and external walls. There are a number of possible reasons for the differences including thermal bridging, high thermal conductivities and excessive air movement in the wall cavities and behind plasterboard dry lining.

This study has been performed as a complement to the graduate studies of Yonghui Jin at the National Institute of Occupational Health and the Royal Institute of Technology. It was initiated by the need to analyze free convective flows along vertical walls within the test chamber employed for experimental work with particle transport in turbulent buoyant plumes.