Building smoke prevention and exhaust systems-News-Leron-Ventilation Specialist

1. System partition

1. For buildings with a building height greater than 100m, the mechanical pressurized air supply system should be set up vertically in separate sections, and the height of each section should not exceed 100m.

2. For public buildings with a building height exceeding 50m and residential buildings with a building height exceeding 100m, the smoke exhaust system should be set up vertically in separate sections, and the height of each section of public buildings should not exceed 50m, and the height of each section of residential buildings should not exceed 100m

3. For the above-ground and underground parts of the stairwell where mechanical pressurized air supply systems are installed, the mechanical pressurized air supply systems should be set up independently. When limited by building conditions and the underground part is a garage or equipment room, the mechanical pressurized air supply system can be shared.

2. Smoke prevention system form

(1) For public buildings, industrial buildings with a building height greater than 50m, and residential buildings with a building height greater than 100m, mechanical pressurized air supply should be used in smoke-proof stairwells, independent front rooms, shared front rooms, shared front rooms and fire elevator front rooms. system.

(2) In the smoke-proof stairwell front room and fire elevator front room in the underground part of the building, when there is no natural ventilation condition or the natural ventilation does not meet the requirements, a mechanical pressurized air supply system should be used.

(3) Closed stairwells should adopt a natural ventilation system. Closed stairwells that cannot meet natural ventilation conditions should be equipped with a mechanical pressurized air supply system. When the closed stairwells of underground or semi-underground buildings (rooms) are not shared with above-ground stairwells and there is only one underground floor, a mechanical pressurized air supply system does not need to be installed, but an openable air vent with an effective area of not less than 1.2㎡ should be installed on the first floor. Exterior windows or evacuation doors that lead directly to the outdoors.

(4) Public buildings, industrial buildings with h≤50m and residential buildings with h≤100m

A. Smoke-proof stairwells, independent front rooms, shared front rooms, shared front rooms (except for shared front rooms shared with fire elevator front rooms) and fire elevator front rooms should adopt natural ventilation systems; when a natural ventilation system cannot be installed, A mechanical pressurized air supply system should be used.

B. When the independent front room or shared front room meets one of the following conditions, the stairwell does not need to be equipped with a smoke prevention system:

Use a fully open balcony or alcove.

There are two or more openable exterior windows with different orientations, and the area of the two exterior windows of the independent front room is not less than 2.0 m2, and the area of the two exterior windows of the shared front room is not less than 3.0 m2.

C. When the mechanical pressurized air supply outlet of the independent front room, shared front room or shared front room is set on the top of the front room or on the wall facing the entrance of the front room, the stairwell can use a natural ventilation system; when the mechanical pressurized air supply outlet When the air outlet is not set at the top of the front room or on the wall facing the entrance of the front room, a mechanical pressurized air supply system should be used in the stairwell.

D. When the smoke-proof stairwell adopts natural ventilation in the part above the height of the podium, the independent front room, shared front room and shared front room of the podium without natural ventilation conditions should adopt a mechanical pressurized air supply system, and the independent front room The arrangement of the air supply vents in the room, shared front room and shared front room shall comply with the provisions of the preceding paragraph.

(5) Mechanical pressurized air supply system for smoke-proof stairwells and front rooms

1) For public buildings, industrial buildings with a building height less than or equal to 50m, and residential buildings with a building height less than or equal to 100m, when an independent front room is used and there is only one door connected to the walkway or room, machinery can be installed only in the stairwell. Pressurized air supply system; when the independent front room has multiple doors, the stairwell and the independent front room should be equipped with independent mechanical pressurized air supply systems.

2) When a shared front room is used, mechanical pressurized air supply systems should be installed independently in the stairwell and shared front room.

3) When scissor stairs are used, the mechanical pressurized air supply systems of the two stairwells and the front room should be set up independently.

(6) Escape routes

1) Mechanical pressurized air supply systems should be installed in the front room and refuge aisle respectively.

2) When a safety exit is set up at one end of the refuge walkway and the total length is less than 30m, or when safety exits are set up at both ends of the refuge walkway and the total length is less than 60m, a mechanical pressurized air supply system can be set up only in the front room.

3. Wind speed requirements

(1) The wind speed of the pressurized air supply outlet should not be greater than 7m/s.

(2) The wind speed of the smoke exhaust port should not be greater than 10m/s.

(3) The mechanical pressurized air supply system should use pipeline air supply, and civil air ducts should not be used. The air supply duct should be made of non-combustible materials and the inner wall should be smooth. When the inner wall of the air supply duct is made of metal, the design wind speed should not be greater than 20m/s; when the inner wall of the air supply duct is non-metal, the design wind speed should not be greater than 15m/s.

(4) The mechanical smoke exhaust system should use pipe exhaust and should not use civil air ducts. Smoke exhaust ducts should be made of non-combustible materials and the inner wall should be smooth. When the inner wall of the smoke exhaust pipe is made of 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-metal, the design wind speed of the pipe should not be greater than 15m/s.

(5) The wind speed of the mechanical air supply outlet should not be greater than 10m/s, the wind speed of the air supply outlet in crowded places should not be greater than 5m/s; the wind speed of the natural air supply outlet should not be greater than 3m/s.

4. Calculation of smoke emission

(1) The design air volume of the smoke exhaust system should not be less than 1.2 times the calculated air volume of the system.

(2) Except for atriums, in places where the net height of the building space is less than or equal to 6m, the smoke exhaust volume shall be calculated as not less than 60m³/(h·㎡), and the value shall be not less than 15000m³/h, or the effective area shall be not less than this Natural smoke exhaust windows (ports) that account for 2% of the room’s floor area.

(3)When a smoke exhaust system is responsible for exhausting smoke from multiple smoke prevention zones, the calculation of the system’s smoke exhaust volume should comply with the following regulations:

A. When the system loads places with the same clear height, for places where the clear height of the building space is greater than 6m, the smoke exhaust volume of the smoke prevention zone with the largest smoke exhaust volume should be calculated; for places where the clear height of the building space is 6m or less , should be calculated based on the maximum sum of the smoke exhaust volumes of any two adjacent smoke prevention zones in the same fire protection zone.

B. When the system burden has places with different net heights, the above method should be used to calculate the smoke exhaust volume required for each place in the system, and the maximum value shall be taken as the system smoke exhaust volume.

5. Fan settings

(1) Mechanical pressurized air supply system

A. The mechanical pressurized air supply fan should be an axial flow fan or a medium or low pressure centrifugal fan.

B. The air inlet of the blower should be directly connected to the outdoors, and measures should be taken to prevent smoke from being inhaled.

C. The air inlet of the air blower should be located at the lower part of the mechanical pressurized air supply system.

E. The air inlet of the air supply fan should not be located on the same surface as the air outlet of the smoke exhaust fan. When difficulties arise, the air inlet of the air blower and the air outlet of the smoke exhaust fan should be arranged separately. When arranged vertically, the air inlet of the air blower should be set below the smoke exhaust outlet. The minimum vertical distance between the two edges should not be less than 6.0m; when arranged horizontally, the minimum horizontal distance between the two edges should not be less than 20.0m.

F. The air blower should be installed at the lower part of the system, and measures should be taken to ensure the uniformity of air supply volume on each floor.

G. The air blower should be installed in a dedicated machine room, and the air blower room should comply with relevant regulations.

H. When a one-way air valve or electric air valve is installed on the air outlet duct or air inlet duct of the air blower, measures should be taken to automatically open the valve in case of fire.

(2) Mechanical smoke exhaust system

A. The smoke exhaust fan should be installed at the highest point of the smoke exhaust system. The smoke outlet should be facing upward and should be higher than the air inlet of the pressurized air supply fan and make-up air fan. The vertical or horizontal distance between the two should comply with relevant regulations.

B. The smoke exhaust fan should be installed in a dedicated machine room, and there should be more than 600mm of space on both sides of the fan.

C. For systems that share a smoke exhaust system and a ventilation and air conditioning system, the shared machine room for the smoke exhaust fan and exhaust fan should meet the following requirements:

An automatic sprinkler system should be installed in the machine room.

Fans and ducts for mechanical pressurized air supply shall not be installed in the machine room.

The connecting parts between the smoke exhaust fan and the smoke exhaust pipe should be able to ensure their structural integrity at 280°C for 30 minutes.

D. The smoke exhaust fan should meet the requirement of continuous operation for 30 minutes at 280°C. The smoke exhaust fan should be interlocked with the smoke exhaust fire damper at the fan inlet. When the valve is closed, the smoke exhaust fan should be able to stop running.

6. Pipeline related requirements

(1) Mechanical pressurized air supply system

A. Vertically installed air supply ducts should be installed independently in duct wells. When difficulties arise, the fire resistance rating of air supply ducts that are not installed in duct wells or share duct wells with other ducts should not be less than 1.00h.

B. When horizontally installed air supply ducts are installed in suspended ceilings, their fire resistance rating should not be less than 0.50h. When not installed in a suspended ceiling, its fire resistance rating shall not be less than 1.00h.

C. The duct well of the mechanical pressurized air supply system should be separated from adjacent parts by a partition wall with a fire resistance rating of not less than 1.00h. When an access door must be installed on the wall, a Class B fire door should be used.

(2) Mechanical smoke exhaust system

A. The smoke exhaust pipe and its connecting parts should be able to maintain their structural integrity at 280°C for 30 minutes.

B. The vertical smoke exhaust pipe should be installed in an independent pipe well, and the fire resistance limit of the smoke exhaust pipe should not be less than 0.50h.

C. Horizontally installed smoke exhaust ducts should be installed in the suspended ceiling, and their fire resistance limit should not be less than 0.50h; when there are real difficulties, they can be installed directly indoors, but the fire resistance limit of the pipe should not be less than 1.00h.

D. The fire resistance limit of the smoke exhaust ducts installed in the ceiling of the walkway and the smoke exhaust ducts passing through the fire protection zone shall not be less than 1.00h, but the fire resistance limit of the smoke exhaust ducts in equipment rooms and garages may not be less than 0.50 h.

E. When there are combustible materials in the suspended ceiling, the smoke exhaust pipe in the suspended ceiling should be insulated with non-combustible materials, and should be kept at a distance of not less than 150mm from the combustible materials.

F. The pipe well where the smoke exhaust pipe is installed should be separated from the adjacent area by a partition wall with a fire resistance rating of not less than 1.00h; when an access door must be installed on the wall, a Class B fire door should be used.

7. Air supply outlet, smoke exhaust outlet, and air supply outlet

(1) Air outlet

A. In addition to the direct irrigation pressurized air supply method, stairwells should be equipped with a normally open louver air supply outlet every 2 to 3 floors.

B. The front room should be equipped with a normally closed pressurized air supply outlet on each floor, and a manual opening device should be installed.

C. The air supply outlet should not be placed in a location blocked by a door.

D. Where a mechanical pressurized air supply system is installed, normally open air vents should be installed in the stairwell and normally closed air vents should be installed in the front room.

(2) Smoke exhaust vent

A. The horizontal distance between any point in the smoke prevention zone and the nearest smoke exhaust outlet should not be greater than 30m.

B. The smoke exhaust outlet should be installed on the ceiling or on the wall close to the ceiling.

C. The smoke exhaust outlet should be located in the smoke storage warehouse, but in areas where the clearance height of aisles and indoor spaces is not greater than 3m, the smoke exhaust outlet can be set at more than 1/2 of the clear height; when it is installed on the side wall, the ceiling The distance from its nearest edge should not be greater than 0.5m.

D. For rooms that require a mechanical smoke exhaust system, when the building area is less than 50 square meters, smoke can be exhausted through the walkway, and the smoke exhaust outlet can be set in the evacuation walkway.

E. In the event of a fire, the automatic fire alarm system will be linked to open the smoke exhaust valve or smoke exhaust outlet in the smoke exhaust area, and a manual opening device should be set up on site.

F. The smoke exhaust outlet should be set up so that the smoke flow direction is opposite to the direction of personnel evacuation. The horizontal distance between the smoke exhaust outlet and the adjacent edge of the nearby safety exit should not be less than 1.5m.

G. The smoke exhaust volume of each smoke exhaust outlet should not be greater than the maximum allowable smoke exhaust volume.

(3) Air supply outlet

When the air supply outlet and the smoke exhaust outlet are arranged in adjacent smoke-proof zones in the same space, the position of the air supply outlet is not limited; when the air supply outlet and the smoke exhaust outlet are arranged in the same smoke-proof zone, the air supply outlet should be located in the smoke storage bin Below the lower edge; the horizontal distance between the air supply outlet and the smoke exhaust outlet should not be less than 5m.

8. Natural ventilation and natural smoke exhaust requirements

(1) Natural ventilation

A. For closed stairwells and smoke-proof stairwells that use natural ventilation, an openable exterior window or opening with an area of not less than 1.0㎡ should be installed at the highest part; when the building height is greater than 10m, it should also be installed on the outer wall of the stairwell. Openable exterior windows or openings with a total area of not less than 2.0 square meters shall be provided on every 5 floors, and the arrangement interval shall not exceed 3 floors.

B. When natural ventilation is adopted in the front room, the area of openable exterior windows or openings in independent front rooms and fire elevator front rooms shall not be less than 2.0 m2, and the area of shared front rooms and shared front rooms shall not be less than 3.0 m2.

C. Refuge floors (rooms) using natural ventilation should be equipped with openable exterior windows in different directions. Their effective area should not be less than 2% of the ground area of the refuge floor (room), and the area in each direction should not be less than 2.0㎡.

D. Openable exterior windows should be easy to open directly. Openable exterior windows installed at high places that are difficult to open directly should be equipped with a manual opening device at a height of 1.3m~1.5m from the ground.

(2) Natural smoke exhaust

A. Places using natural smoke exhaust systems should be equipped with natural smoke exhaust windows (windows).

B. The horizontal distance between any point in the smoke-proof zone and the nearest natural smoke exhaust window (orifice) should not be greater than 30m. When an industrial building uses natural smoke exhaust, the horizontal distance should not be greater than 2.8 times the net height of the building; when the net height of a public building space is greater than or equal to 6m and has natural convection conditions, the horizontal distance should not be greater than 37.5m.

C. The natural smoke exhaust window (port) should be equipped with a manual opening device. If the natural smoke exhaust window (port) is set at a high position and is inconvenient to be opened directly, a manual opening device should be installed at a height of 1.3m~1.5m from the ground. Centralized manual opening devices and automatic opening facilities should be installed in atriums with a clearance height greater than 9m, business halls, exhibition halls, multi-function halls and other places with a building area greater than 2,000 square meters.

9. Other requirements

(1) When natural smoke exhaust is used, the thickness of the smoke storage bin should not be less than 20% of the clear height of the space, and should not be less than 500mm; when mechanical smoke exhaust is used, the thickness should not be less than 10% of the clear height of the space, and It should not be less than 500mm. At the same time, the height of the bottom of the cigarette storage bin from the ground should be greater than the minimum clear height required for safe evacuation.

(2) In areas where the clear height of walkways and indoor spaces is not greater than 3m, the minimum clear height should not be less than 1/2 of the clear height. The minimum clear height of other areas should be calculated according to the following formula:

Hq=1.6+0.1·H′

Note: Hq is the minimum clear height (m); for a single-story space, H′ is the building net height of the smoke exhaust space (m); for a multi-story space, it is the floor height of the highest evacuation floor (m).

Building smoke prevention and exhaust systems

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