Chiltern Dynamics has warned that hospitals are achieving 40% worse air tightness test results than other commercial buildings because of their complexity and ‘poor consideration of design aspects’, said Head of Section: Energy Tom Gregory. ‘We analysed results from 1,500 tests and while hospitals may have managed to scrape a pass, we have seen some spectacular failures, especially in extensions to existing buildings.’
To meet Part L, buildings must achieve air leakage of less than 10m3/hr/m2 @ 50Pa. Mr Gregory said, ‘The hospitals tested scored on average 9, but with pressure on the public sector to meet BREEAM targets and significantly reduce energy consumption, this is not good enough.’
Issues include growth by extension, especially where the original building performs poorly, he added. Key design details are connections to existing buildings and/or plant, detailing at eaves and ground floor and junctions between different constructions. Service penetrations can be problematic, especially once hidden above suspended ceilings, as can penetrations within risers, and ventilated, unconditioned spaces such as plant rooms.
‘Requirements are likely to be ramped up, so contractors need to be targeting better performance now,’ Mr Gregory stressed.
PDF: Hospitals struggle to pass air tightness test
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