How to switch between smoke exhaust and air supply system in case of fire?

First of all, please be strict about the questions of those who are not very clear, so as not to mislead people! In the smoke prevention and exhaust system, the role and place of use of the make-up air system and the positive pressure air supply system are completely different. The make-up air system is set up in conjunction with the mechanical smoke exhaust system to avoid too much negative air pressure in the smoke exhaust area, so that the smoke can be discharged smoothly during the fire.

Make-up air system.

Multi-**** control system.

Just look at the name to know what it is used for.

If it's broken, you have to go to a professional to check it, or you can change it.

Take a look at the process in the central control room? Just found out!

Operating procedures for equipment in the central control room.

1) Purpose: To ensure the safety and accuracy of operation.

2) The scope of application is applicable to the fire fighting equipment and security CCTV system of the building.

3) Responsibilities: The security guard of the central control room is responsible for the operation of the mechanical and electrical equipment in the central control room.

4) Working procedures.

Fire fighting equipment operation work procedures.

a?Fire alarm.

a) System self-test:

b?Fire pumps.

a) Automatic start: The fire pump control cabinet is in the "automatic" position, and when the "fire danger" is in danger, the "fire hydrant alarm box" is smashed on the floor.

Alarm, the linkage cabinet sends out sound and light alarm, and the fire pump is automatically started at the same time.

b) Manual start: Put the selection "Automatic" on the fire pump control cabinet.

General ventilation refers to the make-up air system. The make-up air system is set up at the same time as the smoke exhaust system to avoid too much negative pressure in the smoke exhaust area, so that the smoke can be discharged smoothly during the fire.

This kind of fan is a two-speed exhaust fan, which is used for ordinary exhaust at low speed and smoke exhaust at high speed. The low-speed conversion is given priority to the fire, regardless of whether it is usually turned on or not, and the high-speed operation is linked during the fire to ensure the smoke exhaust requirements.

In the combined system, the fan is a two-speed fan, which usually exhausts air at low speed and exhausts smoke at high speed during fire; The smoke exhaust pipe of the system is equipped with a smoke exhaust valve or smoke exhaust port, which is usually closed and opened in case of fire; The usual exhaust duct is drawn out through the smoke and fire damper, which is usually open and closed in case of fire.

Except for the above-ground part of the building with a mechanical smoke exhaust walkway or a room with an area of less than 500 m2, the smoke exhaust system should be equipped with a make-up air system. The make-up air system should introduce air directly from the outside, and the make-up air volume should not be less than 50 of the exhaust smoke volume. The make-up air system can adopt natural air intake methods such as evacuation external doors, manual or automatic openable external windows, and mechanical air supply methods.

Positive pressure air supply:

When the smoke is exhausted by the fire-fighting machinery, the pressure difference is generated, and the air needs to be replenished to form convective air supply, that is, positive pressure air supply.

When a fire occurs, the internal motor will open the air outlet, the temperature smoke detector or manual fire alarm will be turned on, the positive pressure fan on the top of the tower will automatically open, and the air supply shaft will be pressurized, and the front room of the staircase will continuously supply air to the front room through the positive pressure air supply outlet, so that the front room will maintain positive pressure, ensure that the smoke will not spread in this area, and give people a space to escape. When the temperature is higher than 280 °C, there is no possibility of escape, the internal fuse will be blown and the tuyere will be automatically closed to prevent the spread of fire.

Make-up air system: It is set up with the mechanical smoke exhaust system to avoid too much negative pressure in the air exhaust area, so that the smoke can be discharged smoothly during the fire. The make-up air system can be divided into natural make-up air facilities (including openable external windows and lighting wells, etc.) and mechanical make-up air system.

1. Positive pressure air supply is to supply air to the elevator front room and stairwell, when a fire occurs in the building, the evacuation staircase is the only channel for the evacuation of personnel inside the building, and the front room, the front room is the starting place for firefighters to fight the fire, so it is necessary to carry out smoke-proof design in these parts, in high-rise buildings, there will be a large amount of hot smoke during the fire, which will quickly spread to the upper part through the vertical channel, which is the so-called chimney wind pulling effect. I'm giving you an example, when there is a fire, the personnel are evacuated in the stairwell, at this time, the smoke enters the stairwell, it will cause **, but if there is pressurized air supply in the stairwell, it will cause the air pressure in the stairwell to be greater than the air pressure in the outside fire area, and the smoke will be pushed out and cannot enter, which will play a role in protecting personnel.

2. The fire air supply system is the smoke exhaust system, due to the smoke exhaust system, the pressure difference in the protection area is generated, and the air volume needs to be supplemented, and the air supply volume shall not be less than 50% of the smoke exhaust volume.

It should be determined according to its size and wind pressure. There is no need to distinguish between the need for fire and air supplementation. Please follow the "Code for Acceptance of Construction Quality of Ventilation and Air Conditioning Engineering" (GB 50243---2002).

The material variety, specification, performance and thickness of the metal air duct shall comply with the provisions of the design and the current national product standards. When the design is not specified, it should be implemented in accordance with this specification. The thickness of the steel plate or galvanized steel plate shall not be less than the provisions of the table; The thickness of the stainless steel plate shall not be less than the provisions of the table; The thickness of the aluminum plate shall not be less than the provisions of the table.

Differences: 1. Different places of use:

Positive pressure blowers are generally used in stairwells and elevator front rooms, so that toxic smoke cannot enter. Make-up fans are used in multi-storey basements.

Second, the use of the system is different:

The positive pressure air supply system adopts mechanical pressurized air supply. The make-up air system can be divided into natural make-up air facilities and mechanical make-up air systems.

Third, the use is different:

The positive pressure air supply system is used to prevent the intrusion of smoke and create favorable conditions for the safe evacuation and rescue of personnel. The make-up air system is used to avoid too much negative pressure in the air exhaust area, so that the smoke can be discharged smoothly in the event of a fire.

It's not the same, the fire fan is resistant to high temperatures, the make-up fan is not needed, and it will automatically shut down at 70 degrees.

Make-up air is only for a fireproof partition of an underground garage without a car ramp that leads directly to the outdoors, and according to the specification, the make-up air volume is not less than 50% of the smoke exhaust volume of the fireproof zone. The method is the same as the positive pressure air supply, with no differences.

Is the make-up air the same as the supply air in the fire smoke exhaust system? --Look at the problem should be the smoke prevention and exhaust system of fire fighting! Since it is smoke exhaust, what kind of air supply and air replenishment are mentioned, the logic is not right!

Of course, the air supply is the same, but pay attention to the positive pressure requirements in different areas!

It's the same, it's generally called positive pressure air supply. The aim is to get the smoke out and bring in fresh air to ensure that people don't suffocate to death from the smoke.