This work has been carried out to help develop guidance on siting open flue terminals for natural draught domestic gas boilers. It aims to investigate the effects of adjacent structures and topographical features on wind pressure fields around dwellings, and to identify scenarios where the likelihood of flue flow reversal is high. A combination of wind tunnel testing and computational modelling has been used. Ridge vent pressures on isolated dwellings have also been investigated. For the cases examined, the maximum pressure experienced by a flue terminal above a 45° pitch roof was found to exceed that for an isolated dwelling by up to 60% when very tall or wide structures (eg embankments) were located downwind of the dwelling. The percentage increase was higher for the 30° pitch roof, although absolute pressures for the 45° pitch roof were greater.
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