How to determine the power of positive pressure fans and exhaust fans in large garages?
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This post was last edited by li*ch1968 on 2011-7-1 09:39. How to determine the power of positive pressure fans and exhaust fans in large garages? A 5-story garage, with 20,000 square meters per floor, capable of holding 800 cars. The first floor is 9m high, while floors 2 to 5 are 4.2m high ； Select 2 positive pressure fans and 6 exhaust fans; what are their respective power ratings? What is the supply air pressure in the garage? What should the traffic volume be?
How are fire compartments designated in architectural design? It is recommended to locate fan rooms within these fire compartments. Refer to the Code for Fire Protection Design of Buildings GB50016-2006 for guidelines on this matter. For calculations regarding fan flow rates, consult the 2009 guidelines on HVAC technologies. If a detailed calculation is required, refer to the HVAC design manual; as an estimate, a value of 450–500 PA is generally used
For the flow rate of smoke exhaust fans, refer to Article 8.2.4 of the Code for Fire Protection Design of Garages, Repair Shops, and Parking Lots GB 50067-97. The smoke exhaust capacity of such fans should be determined based on an air exchange rate of not less than 6 times per hour. 8.2.5 The smoke exhaust fans can be centrifugal fans or axial flow fans for smoke exhaust, and smoke exhaust fire dampers that can automatically close when the flue gas temperature exceeds 280°C should be installed on the smoke exhaust branch pipes. The exhaust fan should be able to operate continuously for 30 minutes at 280°C. The smoke exhaust fire damper should interlock to shut down the corresponding smoke exhaust fan. 8.2.6 The wind speed in mechanical smoke exhaust ducts shall not exceed 20 m/s when metal ducts are used ； When using air ducts made of non-metallic materials with a smooth inner surface, it should not exceed 15 m/s. The wind speed at the smoke exhaust outlet should not exceed 10 m/s. 8.2.7 In fire compartments within a garage that do not have direct vehicle evacuation exits leading to the outside, when a mechanical smoke exhaust system is installed, an air supply system must also be provided, with the air supply volume being no less than 50% of the smoke exhaust volume.