Positive pressure air supply In order to ensure the positive pressure value of the smoke-proof stairwell and its front room, the fire elevator room front room and the combined front room, to prevent the positive pressure value from being too large, the evacuation door is difficult to push open, and should be in the smoke-proof stairwell. A front pressure chamber is provided between the front chamber and the front chamber to control the positive pressure air supply pressure. The pressure difference between the positive pressures on both sides does not exceed 50Pa. In order to promote the flow of pressurized air in the anti-smoke stairwell to the walkway and play a role in blocking the flue gas of the fire layer, it is required that the air pressure of the anti-smoke stairwell is greater than the air pressure of the front chamber during the pressurized air supply, and the front The air pressure in the chamber is greater than the air pressure in the aisle. According to the relevant research results, the positive pressure values ​​of the anti-smoke stairwell and the front room, the combined front room, the fire elevator front room and the refuge floor are specified. A range is specified for the positive pressure value in order to comply with the actual situation of the engineering design, and it is easier to grasp and detect. For spaces such as stairwells and front rooms, if the direction of the pressurized air supply force is opposite to the opening direction of the evacuation door, if the positive pressure air supply pressure If the pressure is too high, it will cause difficulty in opening the evacuation door and affect the safety evacuation. On the other hand, the maximum pressure difference overcome by the opening of the evacuation door should be greater than the design pressure of the front room or stairwell, otherwise the need for smoke prevention cannot be met.
The high-quality positive pressure blower is a fan that directs the air in the escape corridor. It sends outdoor wind pressure into the room. When a building fires, it will generate a lot of toxic gases such as smoke and carbon monoxide and block the line of sight. The positive pressure blower will supply air to the escape fire stairs, so that the indoor smoke can not reach the stairs, creating conditions for people to escape. The positive pressure blower is generally installed on the top of the building and is linked with the positive pressure damper of each layer. At the beginning of the fire, the damper is opened, and the positive pressure blower is started, so that the stairwell and the elevator hall are in a positive pressure state (air supply state).
1. When installing the positive pressure blower, pay attention to maintaining the horizontal position of the fan. The joint between the fan and the foundation and the connection of the outlet pipe should be adjusted so that it does not have a strong connection. It is not allowed to add the weight of the pipe to the components of the fan. on.
2. When the fan is installed, all parts should be inspected thoroughly, whether the parts are complete and the joints of the parts are tight.
3. If the positive pressure blower is found to have severe vibration shocks and other abnormal phenomena during operation, it must be stopped immediately.
4. Fans should be protected from rain in the open air.
5. Remove impurities such as ash and dirt inside the fan and prevent corrosion.
In the absence of natural ventilation, the positive pressure air supply pressure sensor of the mechanically pressurized air supply system is the main measure to ensure the safety of the building evacuation stairwell and the front room (the front room) in the fire.
First, the composition of the mechanical pressurized air supply system
The mechanical pressurized air supply system mainly consists of an air supply port, a supply air duct, a blower and an air suction port.
Second, the working principle of mechanical pressurized air supply system
The mechanical pressurized air supply method controls the flow of the flue gas by the gas flow and the pressure difference generated by the blower, that is, when a fire occurs in the building, the air is pressurized and applied to the relevant area outside the fire area to keep it positive. Pressure-proof method to prevent smoke from entering.
In order to ensure that the evacuation passage is free from smoke and air, the personnel are safely evacuated. In the event of fire, from the perspective of safety, the high-rise building can be divided into four safety zones: the first type of safety zone is a smoke-proof stairwell and a refuge floor; The second type of safety zone is the front room of the smoke-proof stairwell, the front room of the fire elevator room or the front room of the combination; the third type of safety zone is the walkway; the fourth type of safety zone is the room. According to the above principle, the pressure of the smoke-proof stairwell should be such that the pressure of the smoke-proof stairwell > the pressure of the front chamber > the pressure of the aisle > the pressure of the room, and also ensure that the pressure difference between the parts is not too large, which causes the difficulty of opening the door to affect the evacuation. When a fire occurs, the mechanically pressurized air supply system should be able to open in time to prevent smoke from entering the corridor, stairwell and front room of the evacuation passage to ensure a safe, reliable and unobstructed evacuation passage and environment for safety. Evacuation provides enough time.
1. Public buildings, industrial buildings and residential buildings with a building height of less than or equal to 50 m and a building height of less than or equal to 100 m. The current room or the combined front room is equipped with a mechanical pressurized air supply system positive pressure air supply port pressure sensor, and its pressurized air supply port is set. Stairwells can be naturally ventilated at the top of the front room or against the wall of the entrance to the front room. When the setting of the pressurized air supply port of the current room does not meet the above requirements, the smoke-proof stairwell shall adopt a mechanical pressurized air supply system. The mechanically pressurized air supply opening of the front room is arranged at the top of the front room, the purpose of which is to form an air curtain for effectively blocking the smoke; and the air supply opening is arranged on the wall facing the entrance of the front room for forming a frontal blockage. The effect of smoke intrusion into the anterior chamber. 2. For public buildings, industrial buildings and residential buildings with a building height of more than 50m, the smoke-proof stairwells and fire-fighting elevators should be equipped with a mechanically pressurized air supply system. 3. When the smoke-proof stairwell adopts the smoke-proof system of mechanically pressurized air supply, the stairwell shall be provided with mechanical pressurized air supply facilities, and the front room may not be equipped with mechanical pressurized air supply facilities, but the front room shall be provided with mechanical plus Pressure air supply facility. The stairwell of the smoke-proof stairwell and the mechanically pressurized air supply system of the combined front room shall be set separately. 4. The smoke-proof stairwell and the front room of the high-rise building with a podium, the front room of the fire elevator or the front room of the fire. When the height of the podium is above, the outer window can be opened for natural ventilation, and the height of the podium is not available. In the case of natural ventilation, the front chamber of the high-rise building without natural ventilation, the front room of the fire elevator or the front room of the combination shall be provided with a local positive pressure air supply system. The air supply opening should also be arranged at the top of the front room or the air supply opening on the wall facing the entrance of the front room.
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