Extract Rates for Office Ventilation

Extract rates should be in accordance with paragraph 3.11. PSV can be used as an alternative to a mechanical extract fan for office sanitary accommodation, washroom and food preparation areas. When an open-flued appliance is provided in a building with mechanical extract, the spillage of flue gases could occur. The open-flued appliance needs to operate safely whether or not the fan is running. Guidance in relation to the interaction of mechanical extract ventilation and open flued appliances is given in Technical Booklet L.