Summary: With the implementation of the national design standard GB51309-2018 "Technical Standard for Emergency Lighting and Evacuation Guidance Systems," the arrangement of emergency lighting in subway stations has transitioned from the traditional decentralized setup of sign and lighting fixtures to centralized control. All equipment status is now integrated into a unified monitoring and management system; emergency lighting fixtures with an installation height of 8 meters or less should use Type A fixtures, and the operating voltage of the lighting fixtures has been changed from AC220V to DC36V.
Keywords: Subway; Emergency Lighting; Centralized Control System
1. Introduction
With the implementation of the national design standard GB51309-2018 "Technical Standard for Fire Emergency Lighting and Evacuation Guidance System" (hereinafter referred to as "the Technical Standard"), the design of emergency lighting systems in subway stations is completely different from the traditional ones. The main changes are as follows: (1) The arrangement of emergency lighting has shifted from the traditional scattered placement of sign and lighting lamps to centralized control, with all equipment statuses integrated into the system for unified monitoring and management. (2) For fire emergency lighting fixtures installed at heights of 8 meters and below, A-type fixtures should be used, and the working voltage of the fixtures has been changed from AC220V to DC36V. Taking the Wujialu Station on Line 10 of the Hangzhou Metro as an example, this article briefly introduces the design application of the emergency lighting and evacuation guidance system in this project.
2. Project Overview
For example, at a certain subway station, the total floor area of the station is 15,149 square meters, and it is an underground two-level island station. The station is equipped with 4 ground exits. The platform level of this station houses a step-down substation, with one cable well at each end of the station and an environmental control and electrical control room at both ends of the concourse. Lighting and power distribution rooms are set at both ends of the concourse and platforms. The main structure is designed for a 100-year service life, the building's fire resistance level is grade one, seismic fortification is set at 7 degrees, and the civil air defense protection level is 6. A step-down substation is located at the B-end of the platform level, which is responsible for the power and lighting load distribution for the station and the two adjacent half-stages.
3. Selection of Emergency Lighting Systems
The fire emergency lighting and evacuation guidance systems (hereinafter referred to as the system) can be divided into centralized control systems and non-centralized control systems based on the control method of fire emergency lighting fixtures. According to Article 3.1.2(1) of the Technical Standard GB51309-2018: Facilities with fire control rooms should choose centralized control systems. The station equipment has a control room (which also serves as a fire control room), and according to the Technical Standard, a centralized control fire emergency power supply and evacuation guidance system should be installed. The emergency lighting controller of the system is installed in the control room on the station platform level. The system includes an emergency lighting controller, an A-type emergency lighting centralized power supply box, emergency lighting fixtures, evacuation guidance lights, communication buses, and more. All equipment and lamps in the system have independent address codes and can communicate with the controller via the bus. The continuous power supply time of the centralized power supply should be the nominal remaining capacity after the battery pack reaches its service life cycle; the centralized power supply control host should not be less than 3 hours, and the centralized power supply distribution box should not be less than 1.5 hours. The equipment and lamps in the system are all manufactured by the same manufacturer, and the products should comply with national standards GB17945 and GB51309, and have the mandatory certification certificate and inspection report from the emergency fire department.
4. Lighting Selection and Luminance Requirements
4.1 Lighting Selection and Power Supply Voltage
Lighting Selection
Emergency lighting fixtures are divided into lighting fixtures and sign fixtures based on the evacuation instruction plan. The lighting fixtures are uniformly equipped with high-brightness LED sources, which offer advantages such as low power consumption, long lifespan, and energy-saving and environmental protection. The light source color temperature of the fixtures should not be lower than 2700K. Sign fixtures are categorized by their installation locations, including safety exit sign fixtures, evacuation exit sign fixtures, directional sign fixtures, floor sign fixtures, and multi-information composite sign fixtures, etc. (See Figure 1).
Image 1
Power Supply Voltage
Our lighting in the Equipment Zone is installed at a height of 3.0 meters from the ground, while the lighting in the Public Area of the Station Hall is at 3.2 meters from the ground, and the lighting in the Platform Public Area is also 3.0 meters from the ground. According to Clause 4 of Article 3.2.1 of the GB51309-2018 Technical Standard, lighting fixtures installed at a height of 8 meters or less from the ground should be of Type A, with a supply voltage of DC 36V.
4.2 Lighting Solutions and Illumination Requirements
Luminary Solutions
Disaster lighting (Type A) and evacuation sign lighting (Type A) are installed in areas such as the station concourse, platforms, access corridors leading to the station exterior, interzone tunnels, equipment rooms, control rooms, fire pump rooms, substation, and distribution rooms. In the event of a fire in the substation, distribution room, environmental control and electrical control room, communication room, signal room, fire pump room, emergency fan room, smoke and exhaust fan room, station control room, and station master's office, backup lighting is required in rooms that still need to operate. Safety exit signs are installed at the exits of each safety exit, including those in gas extinguishing protected areas. The placement of evacuation direction sign lighting between the station concourse and platform sections is arranged at intervals not exceeding 10 meters. Type A emergency lighting centralized power supply boxes are installed in the lighting and distribution rooms at both ends of the station concourse and platform levels, responsible for the distribution and control of evacuation lighting and evacuation sign lighting in the equipment area and the adjacent half-platform public area.
Luminosity requirements
In compliance with the requirements of the "Building Illumination Design Standard" (GB50034-2013) and "Urban Rail Transit Illumination" (GB/T16275-2008), the illumination for all main venues is referenced in Table 1.
Table 1
5. System Power Distribution and Cable Laying
5.1 System Power Distribution
The emergency lighting controller is installed in the vehicle control room, with Type A emergency lighting centralized power supply cabinets set at both ends of the station concourse lighting distribution room and both ends of the platform lighting distribution room. The power for the emergency lighting controller and the Type A centralized power supply cabinet is sourced separately from the fire protection small power double power supply cabinets in the lighting distribution rooms of the concourse and platform levels within their respective fire compartments; the fire power is sourced from different low-voltage busbars of the 0.4kV switchgear room low-voltage cabinets on the platform level. The system illustration is shown in Figure 2.
Figure 2
5.2 Cable Laying
Emergency lighting controllers and centralized power supply cabinets for emergency lighting utilize flame-retardant and fire-resistant shielded twisted pair cables for communication trunk lines. The loop bus employs flame-retardant twisted pair cables, with the loop bus being a two-wire system (i.e., power and communication combined). When the cables are installed openly (including within ceilings), the metal conduits should be protected against fire. For concealed installation, the conduits should be placed within non-combustible structures, with the protective layer thickness not less than 30mm.
6. System Control
The emergency lighting controller continuously inspects the system equipment and lighting fixtures 24/7. In the event of a failure in any device within the system, the controller emits an audible and visual alarm signal, which is automatically cleared after troubleshooting. The emergency lighting controller is equipped with a communication interface protocol with the fire automatic alarm system (hereinafter referred to as the FAS system) alarm host, allowing the FAS system to monitor the strong start-up status information of the emergency lighting and evacuation sign systems. The controller receives fire alarm signals under fire conditions at the station, with the FAS system providing alarm output signals, triggering the system to enter emergency mode and illuminating the emergency lighting.
The corridors in the station equipment area, the rooms for critical equipment, the public areas of the concourse and platforms, as well as the entrance and exit passages, and the emergency lighting in the section tunnels remain unlit during normal operations and illuminate only during fires. In non-fire modes, these lights can also be activated as an emergency measure following a power outage to the normal lighting supply or the main power supply of this system, with an emergency duration not exceeding 0.5 hours. The evacuation signs in the corridors and staircases of the station equipment area, the rooms for critical equipment, the public areas of the concourse and platform levels, and the entrance and exit passages are constantly lit. The evacuation signs in the section tunnels are not lit during normal operations but receive instructions from the FAS system during fire conditions, coordinating with the smoke exhaust direction to guide the evacuation signs to direct passengers towards the fresh air.
During the fire system interlock test at the station, after the fire condition at the station was terminated, the emergency lighting control master unit stopped receiving emergency signals from the FAS system. This was because the normal lighting power supply had been disconnected during the interlock with the fire alarm system, and the non-interlock power supply required manual reset. The corridors in the public and equipment areas of the station had basically lost all lighting. To prevent such occurrences, after receiving the FAS system signal upon termination of the fire condition, the program on the emergency lighting control master unit defaults to no action, and the emergency lighting remains illuminated. The reset and disconnection are then manually performed by staff.
7. Emergency Evacuation System Selection
In summary, the selection of emergency evacuation systems for subway stations typically involves the "central power supply and centralized control" type. The subway tunnel sections are in underground humid environments, while other equipment rooms and public areas are considered standard environments. According to the "Technical Standards," lighting within the area should be selected with a protection level of IP65 or higher. The corresponding product selections are as shown in the following chart.
Controller Host and Central Power Supply Selection
8. Closing Remarks
The implementation of the "Technical Standards" has provided an important technical criterion for the design of our subway emergency lighting systems. From the perspective of subway operation and maintenance, the centralized control required by the standards facilitates future operation and maintenance management, effectively reducing the difficulty of manual inspections and maintenance.
References
[1] "Technical Standard for Emergency Lighting and Evacuation Guidance System (GB51309-2018)" [Standard], 2019.
[2] "Code for Fire Prevention in Building Design" (GB50016-2014/2018 Edition)[S], 2018
[3] "Fire Prevention Standard for Subway Design" (GB51298-2018) [Standard], 2018.
[4] "Standard for Electrical Design of Civil Buildings" (GB51348-2019) [S], 2019.
Wang Li. Practical Application of Fire Emergency Lighting and Evacuation Guidance Systems in Rail Transit Design. Tunnel and Rail Transit, 2021(1): 38-40.
Shi Lingcan. Design Application of Fire Emergency Lighting and Evacuation Guidance System in Subways [J]. China Equipment Engineering, 2023, No. 523(09): 108-110.
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