【 Weak current College 】 mechanical smoke extraction facilities in fire acceptance of problem---Power By 【 China power house network 】

As China's economic construction fast development, high-rise buildings, underground works in some big cities like mushrooms and prospered. Modern high-rise buildings often makes extensive use of plastic decoration, the chemical fiber rug and furniture with foam padding. In the event of fire, Interior fuel and construction materials, decoration materials, flammable furniture, clothing and other combustible materials, such as in the combustion process produces a large amount of toxic smoke and heat, smoke does great harm to the human body, suffocating, poisoning still to death. According to a recent fire deaths statistics indicate that the fire deaths due to smoke smoked death accounted for about 50% to 70%, and burned to death in the majority of first asphyxia collapsed after burned to death. Construction of smoke control facilities in the fire for the safe evacuation and fire fighting created favorable conditions for, and control the fire from spreading. Therefore, the setting is very important for smoke control facilities. In order to design and install smoke control facilities, play, make sure that the State and people's lives and property. Author mechanical smoke extraction facilities in fire acceptance of several opinions on. For reference purposes only.
First, review the settings part of smoke control facility complies with the specifications
(A) mechanical smoke settings parts. Under the high civil building design fire protection standard section 8.3.1 bis provides for the following positions should set the mechanical pressurization smoke control facilities:
1, do not have conditions of natural smoke exhaust smoke fire stairs, elevator room or room before use;
2. adopt the measures of natural smoke exhaust smoke staircases, its does not have natural smoke conditions before the Chamber;
3, closed asylum bed (room).
(B) mechanical smoke extraction settings parts.
1, according to the design of tall building fire code provisions of section 8.4.1: a class of high-rise buildings and building height exceeding 32m II the following parts of high-rise building, you should set the mechanical smoke extraction facilities:
(1) no direct natural ventilation, and longer than the inner passages or 20m although direct natural ventilation, but longer than the inner passages 60m;
(2) more than 100m2, and often someone stay or fuel more ground and set the windowless room or room with a fixed window;
(3) does not have natural smoke conditions or headroom above the Atrium 12m;
(4) in addition to using window wells, and other fenestration for natural smoke rooms, each room has a total area of more than one room area 200m2 or exceed 50m2, and often someone stay or so of more basement.
2, according to the civil air defense air engineering design fire protection standard law, the following part shall be located mechanical smoke extraction facilities:
(1) building area greater than 50m2, and often someone stay or so in more rooms, lobby and c. "workshop;
(2) total length exceeds 20m evacuation aisle;
(3) film and stage.
3, according to the garage, garage, yard design fire protection standard stipulates: over 2000m2 of underground garage should set mechanical smoke extraction system.
(3) dance installstion smoke, smoke extraction facilities set parts. According to the architectural design fire protection standard article 5.1.1 and tall buildings design fire protection standard of 4.1.5A bis, these parts should be fortified to smoke, smoke extraction facilities:
(1) dance installstion located in multi-story building and including four stories above a windowless room or room-room window, underground rooms, as well as more than 20m and no natural smoke evacuation aisle or directly on the natural ventilation, but longer than 40m evacuation in aisle;
(2) dance installstion located in high-rise building of the first floor, second floor, the third layer, the area over the windowless room 100m2 or supposes a fixed window of the room and over 20m and no natural smoke evacuation aisle or directly on the natural ventilation, but longer than 60m evacuation in aisle;
(3) dance installstion located in high-rise buildings up to and including four stories above a windowless room or room-room window, underground rooms, open the window size is smaller than the room area of more than 2%, and with no natural 20m smoke evacuation aisle or directly on the natural ventilation, but longer than 60m evacuation in the aisle.
2. check the system settings for conformance to specifications
(A) of the pressurization system for smoke: 1, more than 32 storey high-rise building is segmentation settings ventilation system; 2, smoke staircases and combined with former rooms are separately set the air supply system, when you must share a system, whether on the way to the front room with air duct pressure difference set on automatic control device; 3, refuge layer is a separate ventilation system; 4, scissors staircase is set independently for the air duct, with the wind as second staircase; 5 ways to determine if the pressure to meet the requirements.
(B) mechanical smoke extraction system: 1, ground and underground is common exhaust system; and 2 whether the individual settings of the Atrium, the exhaust system; 3, mechanical ventilation and smoke extraction system, air-conditioning system and, when combined, whether or not to take the reliable security measures; 4, aisle and room exhaust system is set separately; 5, each exhaust system with exhaust port number is more than 30; 6, basement room is also equipped with air intake system (air mechanical air or natural) into the air should be not less than 50% of the exhaust gas volume and reasonable airflow should be organized so that the smooth discharge of flue gas.
3. view the fan selection is justified.
(A) the smoke pressurization system air supply available look-up or calculation method to determine when the calculated value and the tall buildings design fire protection standard of table 1, table 8.3.2-8.3.2-2, table 3, table 8.3.2-8.3.2-4 inconsistent, whichever the greater value. Then select according to the air or in axial flow fan and low-pressure centrifugal fan.
(B) mechanical smoke extraction system exhaust fan choice whether: 1, when the burden of an exhaust fan for smoke partition, you should press the smoke partition area per square meter than 60m2/h; 2.When the burden of two or more smoke partition should be maximum preventing smoke partition area per square meter than 120m2/h; 3, the volume is less than 17000m3 Atrium, the exhaust gas volume by volume of 6/h ventilation calculation; the Atrium volume greater than 17000m3, its exhaust volume according to the volume of the 4th/h ventilation; but most small amount should not be less than smoke 102000m3/h. According to the size of the calculated value, you can select the centrifugal fans, axial fans, smoke, or you can choose to bring the power of a dedicated exhaust fan.
4. view the air or exhaust port settings location is appropriate
(A) positive-pressure supply outlet: 1, smoke stairway supply outlet is every two to three-layer settings, former room air is layer sets; 2, each supply outlet area size meets the design requirements.
(B) mechanical exhaust outlet: 1, each smoke partition is at least one smoke exhaust vents; 2, smoke partition from the exhaust port within the furthest point of the horizontal distance is more than 30m; 3, exhaust port is located in the ceiling or wall near the ceiling; 4, each exhaust port area size meets the design requirements.
5. test smoke system feature is complete
(A) positive pressure ventilation system: 1, fan distribution meets the requirements, in the last level distribution box office is set up automatic switching devices; 2, fans in fire control room is one of the Start button, in the event of fire, pressure blowers can be started immediately; 3, supply outlet (except for opening pressure air) is set to manually, and automatic opening device, if there are any smoke detector chain of automatic opening device or fire control centre distance control of opening device; 4, smoke staircases, front room, shared room, fire before the elevator room, closed asylum bed (room) residual pressure value is reached the high civil building design fire protection standard article 8.3.7 bis regulations.
(B) mechanical smoke extraction system: 1, fan distribution meets the requirements, in the last level distribution box office is set up automatic switching devices; 2 whether the exhaust outlet, closed weekdays is set manually and automatic opening device, if there are any smoke detector chain of automatic opening device or fire control centre distance control of opening device; 3, in fire control room if there is a fan of one-to-one manual operation button;; 4, when any of the exhaust vents or exhaust valve is opened, the exhaust fan is able to boot; 5, in the exhaust pipes and exhaust fan room entrance is there when the gas temperature of more than 280 ° c, could itself off smoke fire dampers; 6, same smoke partition settings of exhaust port, can be opened simultaneously all exhaust port.
VI. other issues
1. smoke fan downlead of distribution lines with fire performance requirements;
2. air wind speed is not greater than 7m/s, the exhaust vents should not be greater than the wind speed 10m/s;
3, galvanized metal duct, the wind speed should not exceed 20m/s when using concrete block or asbestos Board other non-metallic materials, duct, the wind speed should not exceed 15m/s.
4, headroom than indoor Atrium 12m, vertical exhaust port is 2 to 3 layers of a smoke exhaust vents or segmentation settings;
5¡ ¢ exhaust fan is set in the exhaust system up to the upper part of the exhaust gas outlet does not use the upper to the lower deck of flue gas duct of the arrangement;
6. pressure blower is set free from building fire blower room, it is best to set on the bottom of the system, and the pressurization system of pipes should not be installed for fire dampers.