sealed type and marked with a biohazard symbol. Ideally each isolation should have its If the fan has to be located inside the building, it 2.37 should be as as practicable to the outside. own dedicated supply and extract system. If two or more suites share a ventilation system, there The extract fan motor should be mounted out of the air stream and should be capable of being will be an inevitable increase in the complexity of changed without withdrawing the impeller or the system and a corresponding reduction in reliability and serviceability. Routine maintenance opening up the ductwork. The extract fan should draw or breakdown its power from the essential electrical of the ventilation system will result in failure of system. all suites that it serves; therefore, ideally each such isolation should have its own dedicated Extract filters will not be required provided that 2.35 AHU. the fan can discharge in a safe location 3000 mm above the building height. If extract filters are In a high-rise building, a common supply and 2.38 extract system may be the only feasible solution. fitted, they should be in a change housing” “safe outside the building on the suction side of the fan. In this case, run and standby fans would be Extract filters, where fitted, should be of HEPA required for the extract, and a duplicate supply grade. unit may be considered necessary. The common Even if filtered, extract air should not supply and extract systems will need to be controlled to ensure a constant volume in each be recirculated. isolation suite branch regardless of the number in Extract ductwork, the fan and discharge stack 2.36 use. should be clearly marked to identify the isolation suite that they serve. Service, maintenance, Ductwork should be kept as direct and simple 2.39 cleaning and filter change of the system will be as possible. subject to a permit to work. Figure 1 Extract ventilation negative pressure and PPVL rooms – Extract 3000 mm Spectacle plate E Fire/Plant Pressure Supply Air Handling Isolation damper Unit (AHU ) Plantroom stabiliser Corridor En-suite Patient’s room Lobby Transfer grille Doorway
sealed type and marked with a biohazard symbol. If the fan has to be located inside the building, it should be as as practicable to the outside. The extract fan motor should be mounted out of the air stream and should be capable of being changed without withdrawing the impeller or opening up the ductwork. The extract fan should draw its power from the essential electrical system. 2.35 Extract filters will not be required provided that the fan can discharge in a safe location 3000 mm above the building height. If extract filters are fitted, they should be in a “safe change housing” outside the building on the suction side of the fan. Extract filters, where fitted, should be of HEPA grade. Even if filtered, extract air should not be recirculated. 2.36 Extract ductwork, the fan and discharge stack should be clearly marked to identify the isolation suite that they serve. Service, maintenance, cleaning and filter change of the system will be subject to a permit to work. 2.37 Ideally each isolation should have its own dedicated supply and extract system. If two or more suites share a ventilation system, there will be an inevitable increase in the complexity of the system and a corresponding reduction in reliability and serviceability. Routine maintenance or breakdown of the ventilation system will result in failure of all suites that it serves; therefore, ideally each such isolation should have its own dedicated AHU. 2.38 In a high-rise building, a common supply and extract system may be the only feasible solution. In this case, run and standby fans would be required for the extract, and a duplicate supply unit may be considered necessary. The common supply and extract systems will need to be controlled to ensure a constant volume in each isolation suite branch regardless of the number in use. 2.39 Ductwork should be kept as direct and simple as possible. Figure 1 Extract ventilation – negative pressure and PPVL rooms Extract 3000 mm Spectacle plate Supply Air Handling Unit (AHU ) E Fire/Plant Isolation damper Pressure Plantroom En-suite stabiliser Corridor Transfer grille Patient’s room Lobby Doorway
Service_Specification_Proposition__airborne_HCID__final_for_Stakeholder_testing_1.docx