Thermal modelling – naturally ventilated buildings with heating for the winter months

Where naturally ventilated occupied spaces are heated in the winter/heating season, as an alternative to demonstrating compliance with the winter operative temperature ranges in CIBSE Guide A or other appropriate industry standard, such occupied spaces can demonstrate compliance through meeting the Category B requirements for PPD, PMV and local discomfort set out in Table A.1 of Annex A of ISO 7730:2005. Where this alternative compliance route is used, when these naturally ventilated occupied spaces are in β€˜free-running mode’ (i.e. outside of the winter/heating season), it is not possible to use the ISO 7730:2005 method and therefore these spaces must demonstrate compliance with the requirements to limit the risk overheating in accordance with CIBSE TM52.