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How much do you know about smoke prevention and smoke exhaust?
2021-11-03       Source:尤特森

Concept of smoke prevention and exhaust:


Smoke controlsystem and smoke exhaust system, these two systems combined into smoke control and exhaust system, there is a lot of data in common between the two, but not exactly the same, individually looks very complicated and difficult to remember. Today xiaobian take them out for comparison, I hope to help you clear your mind, easy to remember.


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I. System setting place


one. Smoke control system:


Mechanical pressurized air supply system should be adopted for public/industrial buildings with H > 50m and residential buildings with H > 100m (mechanical must be used regardless of whether the natural opening area meets the requirements);


For public/industrial buildings with H≤50m and residential buildings with H≤100m, natural ventilation can be used (mechanical ventilation should also be used when the natural opening area does not meet the requirements).




B. Smoke exhaust system:


Multi-storey buildings are relatively simple, less affected by external conditions, and generally adopt more natural ventilation. High-rise buildings are mainly affected by natural conditions (such as outdoor wind speed, wind pressure, wind direction, etc.) will be larger, generally adopt mechanical way more. The required opening area in multi-storey buildings should be calculated according to the code directly or according to the smoke exhaust volume and the wind speed at the opening. When the actual opening area is not satisfied, mechanical smoke exhaust should also be used.




two. system section setting


A. Mechanical pressurized air supply system:


If the building height is greater than 100m, the mechanical pressurized air supply system shall be set independently in vertical sections, and each section height shall not exceed 100m.


B. Mechanical smoke exhaust system:


The smoke exhaust system of a public building with a building height of more than 50m and a residential building with a building height of more than 100m shall be set independently in vertical sections. Each section of a public building shall not exceed 50m, and each section of a residential building shall not exceed 100m.


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three. Fan setting position


A. Mechanical pressurized air supply system:


The blower should be set at the lower part of the system, and the blower should be set in a special machine room.smoke control


B. Mechanical smoke exhaust system:


The smoke exhaust fan should be set at the highest point of the system, and the flue gas outlet should be upward. Smoke exhaust fans should be set in a special machine room, and there should be more than 600mm space on both sides of the fan. Smoke control and exhaust system




Four, the fire resistance limit of the pipeline


A. Mechanical pressurized air supply system:


The air supply pipe vertically set in the pipeline should be set independently in the pipeline well. When there are difficulties, the fire resistance limit of the air supply pipe not set in the pipeline well or shared with other pipelines should not be less than 1.00h;


Horizontal air supply pipe, when set in the ceiling, the fire resistance limit should not be less than 0.50h; When not set in the ceiling, the fire resistance limit shall not be less than 1.00h.


B. Mechanical smoke exhaust system:


The vertical smoke exhaust pipe shall be set in an independent pipe well, and the fire resistance limit of the smoke exhaust pipe shall not be less than 0.50h;


Horizontal smoke exhaust pipe should be set in the ceiling, its fire resistance limit should not be less than 0.50h; When there are difficulties, can be directly set in the room, but the fire resistance limit of the pipeline should not be less than 1.00h;


The fire resistance limit of the smoke exhaust pipe set in the ceiling of the corridor and the smoke exhaust pipe passing through the fire protection zone shall not be less than 1.00h, but the fire resistance limit of the smoke exhaust pipe in the equipment room and garage shall not be less than 0.50h.


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Five, the limit of wind speed


A. Mechanical pressurized air supply system:


Piped air supply shall be used and civil air ducts shall not be used. Air supply pipe should be made of non-combustible material and the inner wall should be smooth. When the inner wall of the air supply pipe is metal, the design wind speed should not be greater than 20m/s; When the inner wall of the air supply pipe is non-metallic, the design wind speed should not be greater than 15m/s; The wind speed of the air supply outlet should not be greater than 7m/s.


B. Mechanical smoke exhaust system:


Smoke should be ducted and civil air ducts should not be used. Smoke exhaust pipe should be made of non-combustible material and the inner wall should be smooth. When the inner wall of the exhaust pipe is metal, the design wind speed of the pipe should not be greater than 20m/s; When the inner wall of the smoke exhaust pipe is non-metallic, the design wind speed of the pipe should not be greater than 15m/s. The wind speed of the exhaust port should not be greater than 10m/s.


C. Air supply system:


The wind speed of mechanical tuyere should not be greater than 10m/s, and the wind speed of the tuyere in crowded places should not be greater than 5m/s. The wind speed of natural tuyere should not be greater than 3m/s.




sit. Setting of manual opening device


A. Smoke control system:


A. 1 Natural ventilation: open external Windows should be convenient to open directly. If open external Windows cannot be opened directly at high places, manual opening devices should be set at a height of 1.3-1.5m above the ground.


A. 2 Mechanical pressurized air supply: the front chamber shall have a normally closed pressurized air supply port on each floor, and a manual opening device shall be set.




B. Smoke exhaust system:


B. 1 Natural smoke exhaust: Manual opening device should be set for natural smoke exhaust Windows (openings). Manual opening device should be set for natural smoke exhaust Windows (openings) at a height of 1.3m ~ 1.5m above the ground. Headroom atrium over 9 m, building area of more than 2000 m squared business hall, exhibition hall, multi-function hall and other places, it should be set on the manual open device and automatic open facilities (by the same token, the workshop and warehouse outside the top set can open window, a fire by personnel manual open, so automated priority open means of auto exhaust window).


B. 2 Mechanical smoke exhaust: In case of fire, the automatic fire alarm system linkage opens the smoke exhaust valve or smoke outlet in the smoke exhaust area, and the manual opening device should be set on site.




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