2.2 DETERMINATION OF EXIT REQUIREMENTS
2.2.1 General
The primary purpose of a station is for the use of the transit passengers who normally stay in a station for a period. It shall be no longer than the time necessary to wait for and enter a departing transit vehicle or to exit the station after arriving on an incoming transit vehicle.
2.2.2 Occupant load
a. Occupant load for transit station
R Rationale - Clause 2.2.2aThe occupant load of 0.5m2 per person is derived based on the Level of Service figure. This is a set of qualitative measures that the operators are required to adhere to in relation to quality of traffic service in the transport industry as illustrated in the diagram below. It is also commonly used in evacuation modelling to assess whether the situation is crowded or congested. It takes into account the addition of a single train peak load and the event where there may be a mixed train. It is the maximum allowable number of persons in the station in order for the operator to adhere to the necessary service.
This revised method based on 0.5m2 per person in computing occupant load for transit station will address the maximum permissible number of commuters at the platform during peak travel or unforeseen surge in ridership, in any particular transit station due to changing travel needs. It reflects the actual situation and shall not compromise lift safety during a fire emergency. It is a more reliable measure of the potential capacity that the platform can hold.
Except as required in Cl.2.2.2d. , the occupant load for a transit station shall be calculated based on 0.5m2/person applied across all the station platform areas in accordance with Cl.2.2.2b. , plus the single train-peak load calculated in accordance with Table 1.4.83.
b. Stations with multiple platforms
R Rationale - Clause 2.2.2b These measures are necessary in order to determine if certain platforms may cause commuters to take a longer time to exit the station due to the ratio of the number of exits and the occupant load.For station with multiple platforms, separate scenarios shall be developed with each platform separately considered as the incident platform and all other platforms considered as non-incident platforms.
(1) The incident platform occupant load shall be calculated in accordance with Cl.2.2.2a.; and
(2) All other non-incident platform occupant loads shall be based on 0.5m2/person of the platform area in accordance with Cl.2.2.2c..
Refer to Cl.2.3 for occupant load calculations of typical stations with multiple platforms.
c. Station platform area
(1) For the purpose of calculating the maximum occupant load, the station platform area shall be the standing area measured to the limit of the train length or to the platform end wall, whichever is shorter, and bounded by the following:
(a) the platform screens/ fixed panels along the platform edges; and
(b) 7m boundary parallel to the platform screen/ fixed screens for side platforms (platforms serving only one track).
See Diagram 1.4.80.
(2) Where the station platform shares the same floor as the paid concourse, the station platform area shall include any paid concourse area up to 7m from the platform screen/ fixed screens.
(3) The station platform area shall exclude the following:
(a) Any obstructions including lift shafts, voids, escalators, staircases, seats, areas with headroom less than 2m, rooms, booths, signage, artwork, and railings.
(b) Run-off zones directly in front of escalators and staircases measured 6m from the comb plate for any escalator or last riser for any staircases (whichever is extended further).
(c) Run-off zones directly in front of fare collection gates and turnstiles measured 6m from frontage of the gates or turnstiles
d. Commercial spaces and ancillary areas occupant load
R Rationale - Clause 2.2.2dThese areas must be included because their occupant load will contribute to the time taken to exit the station. Since the same exit staircases and escalators are used, the occupant load will have a direct impact on the calculation of the exit time.
Where there are commercial spaces and ancillary areas in the station,
(1) Occupant load for the commercial spaces shall be determined in accordance with Table 2.2.2d.;
(2) Occupant load in the ancillary areas (excluding E&M rooms) shall be determined based on 10m2 of floor area per person; and
(3) Occupant load in the commercial spaces and ancillary areas (excluding E&M rooms) shall be included in determining the required egress capacity where means of escape from that floor area converge with means of escape serving other station floor areas.
2.2.3 Means of escape from platform public area to point of safety
a. Each platform public area shall be served by at least two means of escape which are independent of and remote from each other from the platform to the exterior of the station. Where the exit staircases are located inside the buffer areas, their locations shall be prominent to the platform passengers by means of exit signs and strobe lights.
R Rationale - Clause 2.2.3aThe provision of at least two means of escape is necessary to ensure that exit is possible even in the event where one means of escape is cut-off. The buffer area is typically located in areas trainways normally not accessible to the public. Taking the behavioural patterns of commuters into consideration, commuters are likely to exit and enter stations through the same entrance. Therefore, it is likely that they will be unaware of an alternate exit route through the buffer area. A prominent sign is thus necessary to serve as a means of awareness during evacuation.
b. Fire safety requirements for Persons with Disabilities (PWDs)
The fire safety requirements for the safe evacuation of PWDs during fire emergency in the station shall be provided.
c. Stairs and escalators
R Rationale - Clause 2.2.3cUnenclosed stairs and escalators can be used for exit capacity computation because the transit stations are transient spaces with low combustible loads.
(1) The stairs (excluding internal exit staircases) and escalators need not be enclosed and shall be included in the exit capacity calculation. Except for stairs at station entrance on ground level, handrails for these stairs shall also comply with Cl.2.2.10f..
(2) Escalators
R Rationale - Clause 2.2.3c.2Escalators are permitted to be considered as means of escape in transit stations as floor areas in the vicinity of escalators are reasonably free of combustibles.
(a) Escalators not fire-separated from the public floor area shall be considered as contributing to the means of escape capacity.
(b) Escalators shall not account for more than 50% of the exit capacity at any one level, including the concourse levels and mezzanine levels.
(c) Due to the possibilities of maintenance or malfunction, one escalator at each station shall be considered as being out of service in calculating egress requirements. The escalators chosen shall be the one having the most adverse effect upon exiting capacities.
(d) The width of the escalator shall be the width of the step tread.
(e) Escalators shall be provided with flat steps at landings which increase in number proportionally with the rise of the escalator as shown in Table 2.2.3c.(2)(e).
| TABLE 2.2.3c.(2)(e): NUMBER OF FLAT STEP AT ESCALATOR LANDINGS | |
|---|---|
| Rise | Number of Flat Steps |
| Up to 6m | Not less than 2 |
| 6 – 18m | Not less than 3 |
| Over 18m | Not less than 4 |
(f) Where operating in the direction of exit travel, escalators shall be permitted to be left in the operating mode during evacuation.
(g) Where escalator can be operated in the direction opposite to exit travel, the escalator shall be provided with stopping devices:
(i) at the escalator; and
(ii) at the PSC and/ or the OCC, except that the escalator shall be fully visible at the remote-control location.
d. Platform evacuation
There shall be sufficient exit capacity to evacuate the platform occupant load from the station platform in 4 mins or less. See Annex 2A.
e. Evacuation to safety
The station shall be designed to permit evacuation from the most remote point of the platform to any one of the following in 6 mins or less. See Annex 2A.
(1) A point of safety
R Rationale - Clause 2.2.3e.1This clause defines the point of safety as a compulsory criterion in any and all evacuations. The point of safety is a safe exterior space located at grade point beyond any enclosing structure or other areas that afford adequate protection for passengers.
(2) For stations with separated concourse and platform levels
Beyond the fare gates (unpaid areas) at the concourse level which is provided with sufficient exit capacity to evacuate people to the external smoothly without any waiting time along the egress routes.
(3) For stations with shared concourse and platform level
Beyond the entrances to subways from concourse unpaid area or the foot of the escalators/ staircases at the concourse level leading to the upper levels, with smoke barriers placed either at the entrances to subways or at the foots of the escalator stairs at the concourse level leading to upper levels, whichever is applicable.
Stations with interchange-link and stations connected to non-transit occupancies shall comply with the relevant requirements of Chapter 9.
f. Fire safety engineering analysis
In lieu of the above requirements stipulated in Cl.2.2.3d. and Cl.2.2.3e., the station can be designed to permit evacuation from the most remote point of the platform to a point of safety through a fire safety engineering analysis. The fire safety engineering analysis shall demonstrate that during station trainway fire scenario, tenable conditions can be achieved for the safe evacuation of all passengers, in accordance with Annex 7A.
R Rationale - ClauseEngineering analysis conducted by fire safety engineers can be an alternative option to prescribed requirements. The analysis must conclude that the environment in the station must remain tenable for the duration of passenger evacuation.
g. Determination of exit capacity
Exit capacity shall be calculated in accordance with Cl.2.2.3h. on the basis of the clear width of means of escape. The clear width of means of escape shall be the minimum width required under Cl.2.2.8 plus, any additional incremental width available.
h. Capacity of means of escape
The capacity of means of escape in person per metre per minute (p/m/min), passenger travel speeds in metres per minute (m/min) shall be as shown in Table 2.2.3h..
i. Capacity of fare collection gates and turnstiles
Except as required by Cl.2.2.3j., the capacity of fare collection gates and turnstiles shall be as shown in Table 2.2.3i..
| TABLE 2.2.3i.: CAPACITY FOR FARE COLLECTION GATES & TURNSTILES | |
|---|---|
| Type of fare collection equipment | Capacity |
| Gates < 850mm wide | 50 p/min per gate |
| Gates >= 850mm wide | 80 p/min per meter |
| Turnstiles | 25 p/min per gate |
j. Gate-type emergency exits
R Rationale - Clause 2.2.3jGate-type emergency exits shall be provided for at least 50% of the required means of escape capacity at the fare control line because there is possibility that turnstile may malfunction due to mechanical failure, unlike the gate-type exits.
(1) Gate-type emergency exits shall be provided for at least 50% of the required means of escape capacity if turnstile-type fare collection gates are used.
(2) Where gate-type emergency exits are provided they shall be electrically operated and deactivated in accordance with Cl.2.2.18.
2.2.4 Means of escape from commercial spaces and ancillary areas
a. Number of exit staircases or exits
Except as permitted by Cl.2.2.4b., Cl.2.2.4d., Cl.2.2.4e., and Cl.2.2.20, there shall be at least two independent exit staircases or other exits from every storey or part thereof, and the exit staircases or other exits shall be remotely located in accordance with Cl.2.2.19. Where a room or space is required to be provided with two exits, each exit shall be of sufficient width to accommodate at least one-half the total occupant load.
b. Single means of escape
Storeys or parts thereof, with rooms that are not high hazard occupancies shall be permitted to have a single means of escape where the maximum travel distance, inclusive of vertical distance complies with Cl.2.2.4g..
R Rationale - ClauseThe single means of exit is deemed adequate as the room it serves is of low fire-hazard.
c. Direct access
Every occupant shall have direct access to the required exit or exits without the need to pass through the spaces or rooms occupied by other occupants, plenums, or horizontal ventilation shafts.
R Rationale - ClauseThis is to ensure that all occupants will have full access to exits since rooms occupied by other tenants may deny them access in the event where the rooms in question are locked.
d. Buffer areas
For rooms located at the buffer areas, the maximum one-way and two-way travel distance shall not exceed 15m and 60m respectively. The determination of travel distance shall be in accordance with Cl.2.2.4h.. Also, in addition to Cl.2.2.4h.(1), it shall also include a door opening directly to the non-incident trainway. See Diagram 2.2.4d..
e. Cable chamber and under-platform services ducts
For cable chamber or under-platform services ducts with headroom less than 2m:
(1) Fixed ladders complying with Cl.2.2.21 shall be acceptable as a means of escape.
(2) Access to fixed ladder at platform level shall not impede the direct path of egress.
(3) Under-platform services ducts shall be provided with at least two means of escape with exits or exit accesses located near the two ends of the under-platform services ducts. Travel distances in Cl.2.2.4d. and Cl.2.2.4g. are not applicable to under-platform services ducts, except that one-way travel to exit or exit access shall not exceed 15m. It is acceptable that exit accesses are provided in the fire-rated wall that separates the under-platform services ducts into two sections as required by Note 8 of Table 6.4A.
R Rationale - Clause 2.2.4e.3As cable chambers and service ducts are only access by maintenance personnel and not regarded as separate storeys in transit stations, such spaces can be provided with cat-ladder in lieu of staircases for evacuation during an emergency.
f. Capacity of exit facilities
The capacity of exits, exit staircases, exit passageways, corridors, exit doors, and other exit facilities shall be measured in units of width of 500mm. The number of persons per unit of width shall be as shown in Table 2.2.4f..
g. Maximum travel distance
R Rationale - Clause 2.2.4gThe time required by occupants to reach an exit during a fire emergency is critical. Maximum permissible travel distance to exits take into consideration that commuters are alert and not likely to be trapped in smoke logged spaces. In general, a minimum of two exits, located remote from each other, shall be required.
EThe maximum travel distance measured in accordance with Cl.2.2.4h. shall not exceed the value as shown in Table 2.2.4g..
Determination of travel distance shall be as follows:
(1) The travel distance shall be the distance measured from the most remote point in the floor area to a door opening directly to
(a) an exit staircase, or
(b) an exit passageway, or
(c) an area of refuge, or
(d) the station public area, or
(2) The most remote point from which the travel distance is measured shall be taken as being 400mm from the enclosure walls of the floor area.
(3) Where permitted under Cl.2.2.10a.(2) for exit staircases to be entered without the provision of an exit door, the travel distance shall be measured to a position where the exit door would be installed if otherwise required.
2.2.5 Smoke-free approach to exit staircase of elevated stations
R Rationale - Clause 2.2.5The smoke-free approach is intended to act as a buffer space for entry into the exit staircase by evacuees and used by firefighters during a fire emergency.
Entry at every storey level (including 1st storey) to an exit staircase of any station or part of a station of more than four storeys above ground level shall be through any one of the following:
a. External exit passageway or external corridor
The openings for natural lighting and ventilation to the corridor shall be located such that they face and are open to any of the following:
(1) an external space, or
(2) a street, service road, or other public space, which is open to the sky, or
(3) an air well which opens vertically to the sky and has a minimum width of 6m and a superficial plan area of not less than 93m².
b. Smoke-free lobby
(1) A smoke-free lobby shall be separated from the adjoining areas of the station by a wall having 1-hr fire resistance.
(2) The exit access door shall have ½-hr fire resistance fitted with automatic self-closing device conforming to the requirements of Cl.3.9.2.
(3) The design of a smoke-free lobby shall be such as not to impede movement of occupants through the escape route.
(4) The floor area of a smoke-free lobby shall be at least 3m² and with minimum clear width of 1.2m. If a smoke-free lobby also serves as a fire lift lobby or serve the firefighting staircase, the floor area shall be not smaller than 6m² and with minimum clear width of 2m.
(5) The floor shall be graded from the lift door towards the lobby door with a fall not exceeding 1 in 200.
(6) A smoke-free lobby, including fire lift lobby, which acts as buffer space for entry into the protected staircase and use by firefighters during emergency, shall be maintained as common property.
(7) A smoke-free lobby shall be ventilated through any of the following:
R Rationale - Clause 2.2.5b.7Smoke-free lobby shall be either naturally or mechanically ventilated to ensure smoke-free in order to provide a reliable means of escape for passenger and access for firefighters.
(a) Permanent fixed ventilation openings which are located in the external wall of the lobby and have a total area of not less than 15% of the floor area of the lobby.
Each opening shall not be less than 1m2 and shall abut an external space or air well, having a minimum clear area of 93m2 and minimum width of 6m and without obstruction vertically throughout the airspace for ventilation. No part of the lobby floor area shall be more than 9m away from the air well or external space.
(b) Mechanical ventilation, which complies with the requirements in Chapter 7.
(c) Cross-ventilated corridor/ lobby which complies with all the following:
(i) The corridor/ lobby shall have fixed ventilation openings abutting an external space. The ventilation openings shall be located on opposite sides of the corridor/ lobby at high level and shall not be less than 50% of the superficial area of the opposing external walls.
(ii) No part of the floor area of the corridor/ lobby shall be at a distance of more than 12m from the ventilation openings.
(iii) The distance of 12m can be measured along the internal corridor via the intermediate ventilation opening to the external space, provided there is no unprotected openings in the walls along the path to the external space. The intermediate ventilation opening shall not be less than 2m in width and 1.2m in height and the width of the path to the external space shall not be less than 2m.
2.2.6 Smoke-free approach in basement
R Rationale - Clause 2.2.6Access to exits must be free of smoke and be available to building occupants at all times. Therefore, a reliable means of escape for commuters and access for firefighters shall be provided via smoke-free access route and staircases. For that reason, providing positive pressure by mechanical ventilation systems to smoke-free lobbies and exit staircases will prevent smoke infiltration. Fire lift lobby can be used by firefighters for rescue and firefighting operations and by passengers with limited mobility such as the elderly or persons with disabilities for emergency escape or transport to a refuge area.
a. In a station comprising more than four basement storeys, entry to exit staircase serving the basement storeys at every basement storey level shall be through smoke-free lobbies;
b. Entry to exit staircase and firefighting staircase at every basement storey level shall be via smoke-free lobby or fire lift lobby in accordance with Cl.4.2.3; and
c. Smoke-free lobby and fire lift lobby shall be required to comply with the relevant provisions under Cl.2.2.5b. and Cl.4.2.3c. respectively. They shall be mechanically ventilated to comply with the requirements in Chapter 7.
2.2.7 Area of refuge and exit reduction
When a floor area has access to area of refuge in compliance with all the requirements in this Clause, the occupant load of the vertical exits can be reduced to ½ when one area of refuge is provided and to ⅓ when two or more areas of refuge are provided.
a. An area of refuge shall be adequate in size to hold the occupant load it receives from the floor area which it serves as provision for required exit. This is in addition to its own occupant load calculated on the basis of 0.3m2 per person.
b. An area of refuge shall be entered through an external corridor and the room, space, or area of refuge shall be separated from the corridor by a wall with at least 1-hr fire resistance.
c. External corridors when used as entry into an area of refuge shall conform to the requirements of external exit passageway for minimum width, changes in floor level, roof protection, enclosure on the open side and provision of opening of wall between the room or space and the exit passageway.
d. Exit doors between the room, space, or area of refuge and the external corridor shall have fire resistance of at least ½ hr and fitted with automatic self-closing device to comply with the requirements of Cl.3.9.2.
e. Every fire compartment in which exit reduction is permitted in connection with area of refuge shall have, in addition, at least one staircase complying with Cl.2.2.10 to exit through the area(s) of refuge.
2.2.8 Minimum width
The minimum clear width of means of escape shall be as follows:
a. 2.3m for platforms measured from the platform screen door to any obstruction;
b. 2.5m for platforms measured from the platform edge to any obstruction;
c. 1.75m for public corridors and ramps;
d. 1m for non-public corridors and ramps;
e. 1m for stairs and exit passageways;
f. 500mm for fare collection gates;
g. 460mm for turnstiles;
h. 850mm for doors and gates; and
i. 500mm for under-platform services ducts.
2.2.9 Dead-end
The maximum length of dead-end shall not exceed 15m (non-sprinkler-protected) or 20m (sprinkler-protected).
2.2.10 Exit staircase
a. Internal exit staircase
(1) Except as permitted in Cl.2.2.3c., an internal exit staircase which serves as the required exit of the station shall be enclosed with construction complying with the provisions of Cl.3.8. The enclosure walls of an internal exit staircase shall not have more than two exit doors opening into the exit staircase shaft at each storey. The two doors shall exclude the final discharge door;
(2) Where an internal exit staircase is directly approached from an external exit passageway or external corridor, it is not necessary to provide such enclosure between the staircase and the external exit passageway or external corridor provided no unprotected openings are located within 3m from the exit staircase; and
(3) There shall be no unprotected openings of occupancy area or combustible material/ construction within 1.5m horizontally or within 3m vertically below any opening including final discharge openings located in the external walls of the internal exit staircase.
R Rationale - Clause 2.2.10a.3The separation distance from nearby openings is required to prevent ingress of smoke and fire spread from nearby unprotected openings.
b. External exit staircase
(1) External exit staircase can be used as a required exit in lieu of internal exit staircase provided it complies with the requirements of exit staircase, except for enclosure of an internal staircase; and
(2) There shall be no unprotected openings within 3m horizontally or within 3m vertically below any part of the external exit staircase.
c. Discharge
All exit staircases shall discharge at ground level directly into:
(1) an external space, or
(2) an open-sided external corridor with no commercial activity and is not more than 5m from the station eave line, or
(3) an open-to-sky corridor having minimum width of 1.2m and two-way escape paths leading to an external space. Any unprotected openings along the corridor shall not be located lower than 1.8m from the floor level, or
(4) In a sprinkler-protected station, a maximum of 50% of the total number of exit staircase can be discharged directly to the ground level covered circulation space provided all the following are complied with:
(a) The discharge point of the exit staircase into the ground level circulation space shall be within sight of and with direct access to an external space.
(b) The maximum distance between the discharge point of an exit staircase and the external space shall not exceed 10m.
(c) Where there are commercial activities e.g. shops or kiosks/ carts located along one side or both sides of the designated escape passageway leading to an external space, a minimum separation distance of 10m shall be maintained between the commercial activities and the designated escape passageway. The circulation space shall also be installed with engineered smoke control system. Alternatively, the commercial activities shall be fire compartmented with walls and doors of minimum 1-hr fire resistance rating.
(d) The clear width of the exit doors leading to an external space shall be adequate to receive the occupant load in the 1st storey circulation space and the total number of people discharging from the internal exit staircases.
d. The minimum width and capacity of exit staircases shall be in accordance with Cl.2.2.3h., Cl.2.2.4f., and Cl.2.2.8.
e. No part along the direction of escape shall be less than the minimum required width for the stairs and landings.
f. Handrails
(1) Every exit staircase shall have handrails on both sides. For exit staircases with only 1.25m or less in width, handrail can be provided at one side i.e., the opposite side shall be either wall, parapet, or grilles;
Exception: Handrails are not required for any staircase having not more than five risers.
(2) Where staircases exceed 2m in width, handrails shall be used to divide the staircase into sections between 1m to 2m of width;
(3) Handrail ends shall be returned to the wall or floor or shall terminate at newel posts; and
(4) Handrails that are not continuous between flights shall extend horizontally, at the required height, at least 300mm beyond the top riser and continue to slope for a depth of one tread beyond the bottom riser.
g. Use of exit enclosure
R Rationale - Clause 2.2.10gRooms should not be enclosed within exit staircase areas as they may act as fire hazards i.e. such rooms may be furnished with furniture, equipment, space dividers and the like.
Where fire-separated exit staircases are provided,
(1) there shall be no enclosed useable space within the exit enclosure, including under stairs; and
(2) the exit enclosure shall not be used for any purpose that has the potential to interfere with egress.
h. Stair identification sign
R Rationale - Clause 2.2.10hSuch sign facilitates passengers and firefighters in knowing which floor they are at within the enclosed stairway.
Staircases shall be provided with a sign with dimensions of at least 300mm x 300mm within the stairwell at each storey landing. The sign as seen in Diagram 2.2.10h. shall contain the following information in the order as follows:
(1) The storey number, at least 125mm in height;
(2) An identification of the staircase in alphabet and/ or number, at least 25mm in height;
(3) The sign shall be located such that it is visible when the door is in the open position and also visible to any person moving up or down the staircase; and
(4) The letters and numbers on the sign can be of any colour that shall contrast with the background colour.
Diagram 2.2.10h.: Stair Identification Sign
i. Ventilation
All exit staircases shall be ventilated by fixed openings in the external walls. Such openings shall be of area at least 10% of the floor area per floor of the staircase, or mechanically ventilated to comply with the requirements in Chapter 7. Exit staircase and occupancy area shall not share the same air well or void for lighting and ventilation.
j. Pressurisation
In any station of which the habitable height exceeds 24m, any internal exit staircases without provision for natural ventilation shall be pressurised to comply with the requirements in Chapter 7. In a station comprising more than four basement storeys, the exit staircase connecting to the fire lift lobby shall be pressurised.
k. Landings
The minimum clear width and length of a landing where there is a change in direction shall not be less than the clear width of the exit staircase.
l. Risers and treads
The height of riser for any exit staircase shall not be more than 175mm and depth of tread shall not be less than 275mm.
m. Headroom
The clear headroom shall be at least 2m measured from the pitch line of the exit staircase or finished floor level of the landing to the underside of any obstruction.
n. Measurement of width
The clear width shall be measured between:
(1) the finished surfaces of the walls, if the staircase is enclosed on both sides by walls only, or
(2) the finished surface of the wall and the inner side of the balustrade, if the staircase has a wall on one side and a balustrade on the other side, or
(3) the inner sides of the balustrades if the staircase has balustrades on both sides.
Note: The projection of handrail into the clear width of a staircase shall not exceed 80mm on each side of the staircase. If the projection exceeds 80mm, the clear width of the staircase shall be measured from the inner sides of the handrails.
2.2.11 Fire escape plan
a. A fire escape plan shall be provided for all station platform and concourse public areas. They shall be located such that they are easily viewable by the occupants passing through these areas which shall include lift lobbies for lift between platform and concourse, ticketing areas at concourse level, smoke-free lobbies, firefighting lobbies and fire lift lobbies. The fire escape plan shall have legible lettering and the fire escape routes made clear to the viewer. It shall clearly show the layout of the floor in the correct orientation and highlight the escape routes (in relation to viewer’s location), escape corridors, and exit staircases using appropriate colours, directional signs and words. The information required on the plan are for firefighting and evacuation purposes and shall include the locations of the following:
(1) PWD lifts;
(2) Hose reels;
(3) Fire extinguishers;
(4) Emergency fire phones;
(5) Passenger Service Centre;
(6) Fire lifts;
(7) Manual alarm call points; and
(8) Rising mains.
b. For ensuring legibility of the fire escape plan for stations with large floor areas, a partial plan of the location where the viewer is standing, showing the escape routes and firefighting provisions located within the area, is acceptable. The plan shall show the egress paths to at least 2 remotely located exits/ exit staircases.
2.2.12 Scissors exit staircase
a. Where two separate internal exit staircases are contained within the same enclosure, each exit staircase shall be separated from the other by non-combustible construction. They shall have fire resistance for a minimum period equal to that required for the enclosure; and
b. Such scissors exit staircases shall comply with all applicable provisions for exit staircase under Cl.2.2.10.
2.2.13 Basement exit staircase
a. Any exit staircase which serves a basement storey of a station shall comply with all the applicable provisions for exit staircase under Cl.2.2.10;
b. Such exit staircase shall not be made continuous with any other exit staircase which serves a non-basement storey of the station; and
c. Basement exit staircases which are vertically aligned with the exit staircases of non-basement storeys shall be separated from such other exit staircases by construction having fire resistance for a minimum period equal to that required for the enclosure.
2.2.14 Spiral staircase
R Rationale - Clause 2.2.14Spiral staircases are not suited as required exits because they are typically steep and winding, thus causing occupants to take a longer time to complete their descent. The varying thread size also leads to the increased risk of occupants slipping and losing their footing.
Spiral staircases shall not serve as required exits unless they comply with all the following conditions. They shall:
a. be external and unenclosed;
b. serve only mezzanine floors, balconies, or any storey of occupant load not exceeding 25 persons;
c. be constructed of non-combustible materials;
d. have a tread length of at least 750mm;
e. be at most 10m high; and
f. comply with the applicable requirements of Cl.2.2.10.
2.2.15 Exit ramp
R Rationale - Clause 2.2.15Ramps are used at floor level transitions to prevent accidents where abrupt elevations may cause tripping.
a. Internal and external exit ramps can be used as exits in lieu of internal and external exit staircases subject to compliance to Cl.2.2.10;
b. The minimum width and capacity of exit ramp shall be in accordance with Cl.2.2.3h., Cl.2.2.4f., and Cl.2.2.8.;
c. The slope of such exit ramps shall not be steeper than 1 in 12;
d. Exit ramps shall be straight with changes in direction being made at level platforms or landings only. However, exit ramps having a slope not greater than 1 in 12 at any place can be curved;
e. Level platforms or landings shall be provided at each door opening into or from an exit ramp;
f. Level platforms or landings shall be provided at the bottom, at intermediate levels where required and at the top of all exit ramps;
g. The minimum width of a platform or landing and length shall be not less than the width of the ramp, except that on a straight-run ramp, the length of the level platform or landing need not be more than 1m;
h. All exit ramps shall be provided with non-slip surface finishes; and
i. Exit ramps serving as means of escape to only one basement storey need not be protected by enclosure walls.
2.2.16 Exit passageways
a. Exit passageways that serve as a means of escape or required exits from any station or storey of a station shall have the requisite fire resistance as specified under Cl.3.3.
b. Internal exit passageway
(1) An internal exit passageway which serves as required exit of the station shall be enclosed with construction complying with the provisions of Cl.3.3;
(2) The enclosure walls of an exit passageway shall not have more than two exit doors opening into the exit passageway. The two doors shall exclude the final discharge door and exit staircase door;
R Rationale - Clause 2.2.16b.2It is essential for staircase enclosures to be smoke-free. Thus, in order to reduce the risk of fire and smoke ingress, there shall be not more than two exit doors and these fire doors will be closed fully in order to act as an effective barrier against the spread of fire and smoke.
(3) Exit doors opening into an exit passageway shall have fire resistance rating as required for exit doors opening into exit staircases, fitted with automatic self-closing device, and complying with the requirements of Cl.3.9.2 for fire resisting doors;
(4) The minimum width and capacity of exit passageway shall comply with the requirements as provided in Cl.2.2.3h., Cl.2.2.4f., and Cl.2.2.8;
(5) Changes in level along an exit passageway requiring less than two risers shall be by a ramp complying with the provisions under Cl.2.2.15; and
(6) If the exit staircase which connects to the internal exit passageway is pressurised, the internal exit passageway shall not be naturally ventilated but shall be mechanically ventilated, and it shall be pressurised to comply with the requirements in Chapter 7.
c. External exit passageway
R Rationale - Clause 2.2.16cAn exit passageway provides the same level of protection from the effects of heat and smoke as an exit staircase, and lead to a point of safety. It is essentially an extension of the staircase. Exit passageway is required when the travel distance from the occupied space to the exit staircase exceeds the required travel distance.
(1) An external exit passageway can be used as a required exit in lieu of an internal exit passageway. This is provided the external wall between the exit passageway and the rest of the floor space can have ventilation openings of non-combustible construction. Such openings shall be fixed at or above a level 1.8m, measured from the finished floor level of the passageway to the sill level of the openings. Such ventilation openings shall be located at least 3m from any opening of an exit staircase;
(2) An external exit passageway may not be subjected to the limitations of a maximum of two exit doors opening into the exit passageway;
(3) An external exit passageway can be roofed over provided the depth of the roofed over portion shall not exceed 3m to avoid smoke logging;
(4) An external exit passageway can be enclosed on the open side by only a parapet wall or solid balustrade of not more than 1m in height; and
(5) Exit doors opening into an external exit passageway shall have fire resistance for at least ½ hr and fitted with automatic self-closing device.
d. Ventilation
(1) Except as permitted by sub-clause (2), all internal exit passageways shall be naturally ventilated by fixed ventilation openings in an external wall, such ventilation openings being at least 15% the floor area of the exit passageway; and
R Rationale - Clause 2.2.16d.1In a fire scenario, there is possibility that exit passageway can become smoke-filled and trap occupants. Therefore, it is essential that internal exit passageways are positively pressurised to prevent smoke infiltration into these spaces.
(2) internal exit passageways that cannot be naturally ventilated shall be mechanically ventilated to comply with the requirements in Chapter 7.
2.2.17 Exit doors and exit access doors
Exit doors and exit access doors shall comply with all the following:
a. Exit/ exit access doors shall be capable of being opened manually;
b. Exit/ exit access doors which are required to have fire resistance rating shall comply with the relevant provisions for fire resisting doors under Cl.3.9.2; and
c. Measurement of door width
(1) In the case of an exit/ exit access door having a single leaf door, the opening shall be measured between the edge of the door jamb and the surface of the door when opened at an angle of 90°. See Diagram 2.2.17c.(1).
(2) In the case of a 2-leaf exit/ exit access door fitted with an approved automatic flush bolt, the clear openings shall be measured between the surface of one leaf to the other door leaf when opened at an angle of 90°.
(3) If one of the door leaves is bolted to the door frame and/ or floor by a manually operated bolt, this door leaf shall not be considered for the purpose of determining the exit capacity of the door. The opening of the other door leaf shall have a clear width of not less than 850mm, measured between the edge of the bolted door leaf and the surface of the other door leaf, when opened at an angle of 90°.
(4) Door hardware and handrails which do not protrude more than 80mm into the clear width of exit opening can be disregarded.
d. Exit doors and exit access doors shall open in the direction of exit travel:
(1) when used in an exit or protected enclosure, or
(2) when serving a high hazard area, or
(3) when serving a room or space with more than 50 persons.
e. Exit doors opening into exit staircases and exit passageways
(1) The doors shall not impede the egress of occupants when swung open in accordance with Diagram 2.2.17e.(1); and
(2) The corridor’s clear width shall remain to be at least half of the required clear width as stipulated in Cl.2.2.8 when such door(s) is swung open.
Exception: Exit access doors of plant rooms in buffer areas.
f. The maximum exit doors and exit access doors opening force shall be 30N at 0º and 20N at 30º opening.
g. Vision panel
The fire door to a protected staircase and smoke-free/ fire lift lobby shall be constructed to incorporate a vision panel. The vision panel shall have a clear view size of 100mm width by 600mm height. The vision panel shall have the requisite fire resistance rating and shall not turn opaque when subject to heat. The bottom edge of the vision panel shall be located at 900mm above the finished floor level.
R Rationale - ClauseTo enable firefighters to appreciate the situation before entering to the occupied space and prevent door opening into the staircase from accidentally hitting someone behind the fire door.
h. Revolving doors shall not be used as exit doors for required exits.
R Rationale - Clause 2.2.17hDue to high possibility of jamming, revolving doors cannot be accepted as exit doors for escape purposes. When revolving doors are present, adjacent exit doors shall be provided and indicated clearly as such.
i. Where exit/ exit access doors in a means of escape are used in pairs,
(1) Approved automatic flush bolts shall be provided; and
(2) The unlatching of any leaf shall not require more than one operation.
j. Panic exit device
Latched exit doors in a means of escape from an area having an occupant load of 100 persons or more shall be equipped with approved panic exit device. The panic exit device shall operate to open the door when a pressure is applied on the bar in the direction of travel and be appropriately marked “Push Bar To Open” in letters not less than 50mm high.
k. Electrically operated doors in means of escape path
Where doors located in the required means of escape path are operated by power upon the approach of a person, the doors shall automatically open and remained at the fully open position,
(1) Upon activation of the station’s fire alarm, or
(2) In the event of a loss of power to the door.
l. Access control using smart card locking device, electromagnetic/ electromechanical locking device
(1) The doors shall be unlocked in the event of a loss of power to the lock.
(2) Where access control using electromagnetic/ electromechanical locking device is installed on any exit access door and/ or exit door, such doors shall comply with the requirements stipulated in Table 2.2.17l.(2) - 1 & 2.
2.2.18 Fare collection gates and turnstiles
R Rationale - Clause 2.2.18Fare collection gates and turnstile shall be of sufficient width to be used as exits in the course of evacuation by passengers during an emergency.
a. Fare collection gates, when deactivated, shall provide a minimum clear width in accordance with Cl.2.2.8f.. Consoles shall not exceed 1.1m in height.
b. A turnstile-type fare collection gate shall provide a minimum clear width in accordance with Cl.2.2.8g.. Maximum height of the turnstile bar shall not exceed 1m.
c. Fare collection gates and turnstiles shall be designed to be deactivated automatically in the following events:
(1) A loss of power to the lock.
(2) Upon activation of a manually operated switch accessible to authorised personnel within the PSC, in the absence of which, at the OCC.
d. When deactivated:
(1) Freewheel or open in the exit direction; and
(2) Permit movement of passengers in the exit direction regardless of any failure to operate properly.
2.2.19 Two-way escape (Remoteness of exits)
Where more than one exit is required from an area, a room or a compartment, such exits shall be remotely located from each other and shall be arranged and constructed to minimise the possibility that more than one can be blocked by any one fire or other emergency condition. The following shall be complied with:
a. If two exits or exit access doors are required, they shall be placed at a distance from one another equal to or not less than half the length of the maximum overall diagonal dimension of the compartment or area to be served, measured in a straight line between the furthest edges of the exit doors or exit access doors. See Diagram 2.2.19a. - 1 to 6. If the distance between the two exits is less than half the length of the maximum overall diagonal dimension of the compartment or area to be served, it shall be considered as a one-way escape arrangement.
b. In rooms or compartments protected throughout by an approved automatic sprinkler system which complies with the requirements of Chapter 6, the minimum separation distance between two exits or exit access doors measured in accordance with Cl.2.2.19a. shall be not less than one-third the length of the maximum overall diagonal dimension of the compartment or area to be served.
c. Where exits are inter-connected by a corridor, exit separation shall be permitted to be measured along the line of travel within the exit access corridor. The exit access corridor connecting the exits shall be protected by at least 1-hr fire rated enclosures. Doors opening into this corridor shall have at least ½-hr fire resistance rating. See Diagram 2.2.19c..
2.2.20 Non-habitable roof
Effective Date: 1 Sep 2024
This clause addresses means of escape for non-habitable roofs.
For non-habitable roof described in Cl.1.4.48, at least one exit staircase shall be provided. Where the area of non-habitable roof is large and one-way travel distance to the exit cannot be met, an additional fixed ladder in accordance with Cl.2.2.21 and adequately separated in accordance with Cl.2.2.19 and leading to the circulation area of the floor below shall be acceptable as a means of escape.
2.2.21 Fixed ladders
R Rationale - Clause 2.2.21 This clause entails fixed ladder and access hatches requirements.a. Fixed ladder shall comply with ANSI A14.3, or BS 5395: Part 3, shall be acceptable as a means of escape.
b. Any access hatches to access the fixed ladder, if provided, shall be readily openable and accessible from both above and below.
c. Access hatch openings shall have a minimum clear width of 1m.
d. The travel distance on the fixed ladder shall be measured as the vertical distance multiplied by a factor of 2.