Design of Automatic Fire Alarm System for Subway

Subway is the most convenient and most mobile public place in the city. It has unparalleled advantages over other modes of transportation. However, due to the special characteristics of the subway itself, the losses caused by accidents are immeasurable. However, since the appearance of the subway, fire has also been one of the most frequent accidents.

Subway fires have the characteristics of suddenness, poor crowd escape conditions and difficulty in extinguishing fires. As an important means of preventing and controlling fire, the automatic fire alarm system has very important significance in the application of subway. It can effectively detect and monitor the entire subway running route, and can quickly identify fire signals in a short time. Issue fire alarm information and initiate linkage emergency facilities to achieve the safe operation of the subway. How to scientifically and standardly design the subway fire automatic alarm system will be an important basis for the full play of fire prevention and control.

I. General requirements for design of automatic fire alarm system for subways

1. From the perspective of the installation location, automatic fire alarm systems should be set up for stations, section tunnels, substations and system equipment rooms, main substations, centralized cold stations, control centers, and vehicle bases in the subway.

2. The classification of the objects to be protected by the automatic fire alarm system shall be based on the nature of its use, fire risk, evacuation, and difficulty of extinguishing, and shall comply with the following provisions:

(1) For underground stations, interval tunnels and control centers, the protection level shall be one class;

(2) Centralized air-conditioning systems or ground-based stations and elevated stations with a floor area of ​​more than 2,000 but not exceeding 3,000 in each floor shall be provided. The degree of protection shall be two, and the degree of protection exceeding 3,000 shall be one class.

3. The design of the automatic fire alarm system for subways shall also comply with the relevant provisions of the current national standard "Code for the Design of Automatic Fire Alarm Systems" GB 50116.

Second, the composition and function of the system

1. The automatic fire alarm system shall have automatic fire alarms, manual alarms, communication and network information alarms, and shall implement control of fire disaster relief equipment and linkage control with relevant systems.

2. The automatic fire alarm system shall consist of a central-level monitoring and management system set up at the control center, a station-level monitoring and management system at the station and vehicle base, on-site monitoring equipment and related communication networks.

3. The central level monitoring and management system of the fire automatic alarm system should consist of operator workstations, printers, communication networks, uninterrupted power supply and display devices, and should have the following functions:

(1) Receive the fire disaster information of the whole line, and monitor and control the fire protection system and facilities of the line;

(2) issuing fire control commands concerning the station's fire fighting equipment;

(3) Receiving and storing the main operating status of fire alarm equipment across the line;

(4) To communicate with the fire automatic alarm systems such as stations and vehicle bases;

(5) Archival management of fire incident history data.

4. The station level of fire automatic alarm system should be composed of fire alarm controller, fire control room graphic display device, printer, uninterrupted power supply and fire control linkage controller manual control panel, and should have the following functions:

(1)Communicate with the central level management system of the fire automatic alarm system and the field level monitoring system of the station;

(2) Real-time fire alarms within the scope of jurisdiction to monitor the fire disaster within the jurisdiction of the station;

(3) Collect and record fire information, and report to the central monitoring and management level of the fire automatic alarm system;

(4) Display of fire alarm points, operation status of anti-knockout and disaster relief facilities and location screen;

(5) Control the start and stop of subway fire disaster relief equipment and display the operating status;

(6) Accept the central level fire automatic alarm system directive or disaster relief within the scope of independent organization, management, and command;

(7) Issue fire linkage control instructions.

5. The fire control system's on-site control level shall consist of input and output modules, fire detectors, manual alarm buttons, fire-fighting telephones, and on-site networks, and shall have the following functions:

(1) Monitor the disaster situation within the jurisdiction of the station and collect fire information;

(2) Low-frequency inspection signals, running status, equipment failures, and pipe pressure signals of the fire pump;

(3) Monitor the operating status of the fire protection power supply;

(4) Monitor the working status of all fire fighting equipment at the station.

6. The information transmission network for the automatic fire alarm and linkage control of the whole subway line shall use the public communication network of the subway, and the field-level network of the fire automatic alarm system shall be independently configured.

Third, fire linkage control

1. The fire-fighting linkage control system shall implement the hydrant system, automatic fire extinguishing system, smoke prevention and smoke exhaust system, as well as fire power and emergency lighting, evacuation instructions, fire shutter, electric smoke curtain, fire radio, ticket inspection machine, platform doors, Access control, escalator and other systems in the case of fire linkage control of fire.

2. The control of the hydrant system should meet the following requirements:

(1) The start and stop of the fire pump should be controlled;

(2) The station comprehensive control room (fire control room) should be able to display the work, failure and hand/automatic switch status of the fire pump, and the working position of the fire hydrant button, and the direct manual start and stop of the fire hydrant pump should be realized;

(3) The station-level fire automatic alarm system shall control the switch of the fire-fighting water mains electric valve and shall display its working status;

(4) The fire hydrant of the fire pump shall be provided with a fire hydrant pump start button, and a signal for starting the fire pump may be sent to the fire control room.

3. The station fire automatic alarm system shall display the state of the alarm, air jet, and damper of the automatic fire extinguishing system protection zone, and the state of the hand/automatic transfer switch.

4. The control of smoke prevention and smoke exhaust system shall meet the following requirements:

(1) The fire should be confirmed by the automatic fire alarm system, and the predetermined smoke prevention and smoke exhaust mode instructions should be issued;

(2) It should be directly controlled by the fire automatic alarm system, and the environmental and equipment monitoring system or the integrated monitoring system can also receive instructions to execute linkage control of non-fire-fighting special equipment involved in the prevention and emission of smoke;

(3) After the environment and equipment monitoring system or the integrated monitoring system accepts the fire control instruction, priority shall be given to the mode conversion, and the instruction execution signal shall be fed back;

(4) Equipment directly linked to the automatic fire alarm system shall display the operating mode status on the fire alarm display.

5, station fire automatic alarm system For the fire pump and special smoke, smoke exhaust fan, in addition to automatic control should be set up, should be set up manual control; for smoke, smoke exhaust equipment should also set up manual and automatic mode control device.

6. The control of fire power, emergency lighting and evacuation instructions shall comply with the following provisions:

(1) After the fire automatic alarm system confirms the fire, the fire control equipment shall cut off the non-fire power supply in the relevant area according to the fire district in the power distribution room or the substation;

(2) After the automatic fire alarm system confirms the fire, the emergency lighting and evacuation marker lights should be turned on and the working status should be monitored.

7. The control of fire-fighting linkage to other systems shall meet the following requirements:

(1) The broadcast shall be converted into fire emergency radio status automatically or manually;

(2) The CCTV system shall automatically or manually switch to the relevant screen;

(3) The ticket gate shall be opened automatically or manually, and its working status shall be displayed;

(4) The station platform doors shall be opened or closed automatically and manually according to the fire operation mode or working conditions, and the working status shall be displayed;

(5) The fire zone access control should be automatically unlocked, and all access control should be manually unlocked;

(6) Fire shutter doors and electric smoke curtains should be automatically landed and should display working status;

(7) The elevator shall be forced down to the first floor and shall receive the feedback information of the state of the elevator. In the state of personnel monitoring, the elevator shall stop or stop the escalator.

8. Fire-fighting linkage controller control should be connected with various types of modules with addresses through multiple bus loops. The number of address modules with each bus loop connection should have a certain margin.

9. Between each line fire automatic alarm system set up at the transfer station branch line, information exchange and fire fighting linkage shall be implemented through the mutual information module, information reproduction screen and fire-fighting telephone extension (or jack).

Fourth, the setting of fire detectors and alarm devices

1. The automatic fire alarm system shall be equipped with both automatic and manual triggering devices.

2. The alarm area should be divided according to the fire partition and equipment configuration.

3, the location of the fire detector should be compatible with the level of protection objects.

4. The division of the detection area should meet the following requirements:

(1) Each smoke-preventing area in a large space such as a station hall or platform should be divided into independent fire detection areas. The area of ​​a detection area should not exceed 1000m2.

(2) The division of detection areas in other parts shall comply with the relevant provisions of the current national standard “Design Criteria for Automatic Fire Alarm Systems” GB 50116.

5. Stations and halls of underground stations: public areas, platforms, public areas, transfer public areas, various equipment rooms, warehouses, duty rooms, offices, corridors, power distribution rooms, cable tunnels or mezzanines, and entrances and exits over 60m in length. Channels, fire detectors should be set up.

6. Fire detectors shall be installed on enclosed stations and halls of ground and elevated stations, various types of equipment rooms, management rooms, power distribution rooms, cable tunnels or mezzanines.

7. Fire detectors shall be installed at the vehicle parking workshops, maintenance workshops, important equipment rooms, flammable goods warehouses, power distribution rooms, and places with high fire risk at the control center and vehicle base.

8 There should be two types of automatic fire alarm detectors in the room where the gas is automatically extinguished.

9. A manual alarm device should be set in the place where the fire detector is set.

10. The manual alarm button shall be set at the entrance and exit passages of the underground tunnel and the length of more than 30m. The setting range of the manual alarm button in the interval should be combined with the position of the fire hydrant in the interval.

11. It is not advisable to set up an alarm sound in public areas where passengers are active, and alarm bells should be set up in corridors of office areas.

V. Fire Control Room

1. The automatic fire alarm system central level monitoring and management system shall be set in the control center dispatching hall and should be close to the traffic scheduling.

2. The station fire control room shall be set in conjunction with the station comprehensive control room. The fire control room shall be equipped with a fire alarm controller, a fire-fighting linkage controller, and a fire control room graphic display device.

3. The fire control room at the transfer station should be set up centrally. Fire control rooms set up by line should be able to transmit and display status information between each other, but should not be mutually controlled.

4. The fire control room shall be able to monitor the fire detection alarm and linkage control system, fire hydrant system, automatic fire extinguishing system, smoke and smoke exhaust system, fire door and rolling blind system, fire power, fire emergency lighting and evacuation indication system in the protection area. Firefighting communications and other types of firefighting systems and systems in various types of firefighting facilities, and should display all types of firefighting facilities, dynamic information and fire management information.

5, the fire control room should be able to control the working status of the fire or light alarm.

Sixth, power supply, lightning protection and grounding

1. The automatic fire alarm system shall be provided with a main power supply and a DC backup power supply; the load rating of the main power supply shall be one class.

2. The DC standby power supply for the fire automatic alarm system should be powered by a dedicated battery or a battery set in a centralized manner. The capacity of the DC standby power supply should ensure continuous power supply for 1 h after the main power supply is turned off. When centralized storage batteries are used, the fire alarm controller power supply circuit should be set separately.

3. The power supply of the fire automatic alarm system graphic display device and fire communication equipment should be powered by the UPS power supply device or the battery type emergency control power supply system.

4. The fire-fighting electricity equipment should adopt a dedicated power supply circuit, and its distribution lines and control loops should be divided according to the fire prevention zone.

5. The grounding resistance of the automatic fire alarm system grounding device shall meet the following requirements:

(1) When using a general grounding device, the grounding resistance should not exceed 1Ω;

(2) When using a special grounding device, the grounding resistance should not exceed 4Ω.

6, fire alarm system should be set equal potential connection network. The metal enclosures, cabinets, racks, metal pipes, slots, surge protector (SPD) grounds, etc. of electrical and electronic equipment should all be connected to the grounding terminals of the equipotential bonding network at the shortest distance.

Seventh, wiring

1. In addition to the requirements for the automatic alarm device technical requirements, the selection of the core cross-section of the fire automatic alarm system transmission line should still meet the requirements for mechanical strength. The minimum cross-sectional area of ​​copper core insulated conductors and copper core cable cores shall not be less than the requirements in Table 1 below.

Table 1 Minimum cross-sectional area of ​​copper core insulated conductor and copper core cable core (m)

2. The transmission lines of the fire automatic alarm system should be routed through a metal pipe or enclosed trunking protection.

3. The transmission lines of the automatic fire alarm system laid horizontally shall not penetrate the same pipe when the pipe is used for wiring.

4. The wires and cables used in the automatic fire alarm system shall comply with the relevant provisions of the Metro Design Code GB50157 2013.

The above content is for technical exchanges only. The site design and construction should be based on the specific conditions of the site and related national standards and regulations. Any decision, act or omission done in accordance with the above content shall be the responsibility of the actor.