Annex J(Clause 6.4.4)

Fire and Life Safety Requirements for Metro Stations

J-1 Application and Scope

The provisions of this annex relates to the buildings constructed as part of the metro stations/metro rail systems.

J-2 Terminology Associated with Metro Facilities

For the purpose of this annex, the terminologies given at 2.43 shall apply.

J-3GENERAL

J-3.1 Classification

Metro stations can be classified under ‘Assembly occupancies’. These shall include any station building or part thereof, permanent or temporary, through which people transit for the duration of time required to enter the building and board the train to depart the station platform or to alight from the train and depart from the station building.

J-3.2 Sub-classification

Metro stations can be further classified under the following headings:

a) Elevated and enclosed stations,

b) Elevated and open stations, and

c) Underground stations.

NOTE — The above shall include all open and enclosed Metro Stations along with their associated ancillary structures and train depots. Elevated shall mean to include ‘at-grade’ stations as well.

J-3.3 Fire Zones

Metro stations, that is, mass rapid transit may be constructed within Fire Zone No. 1, 2 or 3, as per the transportation requirement.

J-3.4 Type of Construction

Metro stations shall conform to Type 1 or Type 2 or combinations of Types 1 and 2 non-combustible constructions, as defined in 3.3.

J-4 Life Safety Requirements

a) Main occupant load in a transit station is the platform occupant load, on which basis the life safety provisions of transit stations are designed. Occupant loads in transit stations are mainly a function of the train carrying capacities rather than the areas of a station.

b) For calculating platform occupant loads for a multiline, multilevel or multiplatform station, maximum occupant load for each platform shall be considered separately for determining the egress capacity from that platform.

c) At levels where egress routes from separate platforms converge, occupant loads of all platforms shall be considered to calculate egress capacity from that level. Simultaneous loads shall be considered for all egress routes passing through each level of that station.

d) Platform occupant load shall be based on the greater of the AM or PM ‘peak hour loads’ generated by the system and train loads.

e) Peak hour load shall be converted to peak minute loads by dividing by 50 and multiplying further by a system surge factor varying from 1.15 to 1.5, as defined by the transit system authority. Surge factor may require to be further enhanced where increased footfalls are anticipated like stations catering to sports complex, etc.

f) Platform occupant load shall be determined by factoring in the peak hour entraining loads at platform edges and train loads, in emergency evacuation scenario, as defined here:

1. Train on fire — It is assumed that a train loaded to crush capacity travelling in peak direction at peak hour has caught fire, and as per the operating procedure it is brought to the next station, whereupon it shall require to be evacuated.

2. The train in this case being called the ‘incident train’ and the platform on which it is arriving being called ‘incident platform’ of the ‘incident station’.

3. Passengers waiting on all the platforms of the ‘incident station’ shall require to be evacuated as well.

4. Number of passengers shall be determined as defined in (g) below.

5. Only one source of fire, that is, train fire shall be assumed at a time.

6. It is assumed that the train on non-incident platform shall not stop at the incident station and shall stop only at previous/next station.

g) Platform occupant load, for emergency evacuation scenario, shall be the addition of two headway entraining loads for peak direction platform, one headway entraining load for off-peak direction platforms and one crush train load.

NOTE — See also J-4.1(b) and J-4.1(c).

h) Occupancy in non-public areas:

1. Use of designated non-public areas by station staff whose work assignments require their presence in the station structures shall be permitted.

2. Unmanned plant rooms and any other areas where usual occupancy is less than 10 persons at any given time shall be treated as unoccupied areas.

j) Segregation with non-transit occupancy:

Non-transit occupancies, of area up to $250\mathrm{m}^2$

shall be permitted to be accommodated within the station building. Occupant load of areas under non-transit occupancies shall be in accordance with Table 3.

J-5 Egress Provisions

a) Means of egress — Public areas — Egress from metro station shall be designed to facilitate the evacuation of a pre-defined platform occupant load to a designated point of safety in pre-defined emergency scenario(s), as defined by the transit system authority.

b) Evacuation time from platform — Enough egress capacity shall be provided to evacuate the platform occupant load within 4 min from enclosed stations and within 5.5 min from open stations.

c) Evacuation time to point of safety — Further, station design should permit evacuation of the remotest person on platform to a point of safety within 6 min in case of enclosed stations and within 8 min in case of open stations.

NOTE — Evacuation time specified in (b) and (c) may be modified based on actual engineering analysis by evaluating material heat release rates, station geometry and emergency ventilation systems.

d) For open stations where the concourse is below or protected from the platform by distance or materials as determined by an appropriate engineering analysis, that concourse shall be permitted to be defined as a point of safety.

e) For enclosed stations equipped with an emergency ventilation system and where the emergency ventilation system provides protection for the concourse from exposure to the effects of a train fire at the platform as confirmed by engineering analysis, that concourse is permitted to be defined as a point of safety.

a) Means of egress from each station platform shall be provided so that they are equally distributed as far as possible, in capacity and placement, throughout the length of platform.

b) There shall be at least two means of egress remote from each other.

c) Means of egress may however be allowed to converge at concourse or subsequent levels with sufficient capacity to achieve the required evacuation time.

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d) As far as possible, all the egress capacity required for emergency evacuation shall be provided with the unenclosed stairs and escalators which are used for normal circulation.

J-5.3 Travel Distance

The maximum travel distance on the platform to a point at which a means of egress route leaves the platform shall not be more than 100 m. This shall however be subject to fulfilling the egress requirements specified in J-5.2.

J-5.4 Means of Egress

J-5.4.1 Non-public Areas

Means of egress from unoccupied non-public areas shall be permitted to be merged into public means of egress.

J-5.4.2 Non-transit Occupancies

Separate means of egress shall be provided for such non-transit occupancies which are segregated from the station public area to ensure independent evacuation from either occupancy. Such means of egress may be allowed to converge beyond station concourse area with the approval of the competent authority.

Platforms, corridors and ramps serving as means of egress shall be designed as per following criteria:

a) A minimum clear width of 1 200 mm shall be provided along all platforms, corridors, and ramps serving as means of egress.

b) In computing the means of egress capacity available on platforms, corridors, and ramps, 300 mm shall be deducted at each sidewall, and 450 mm shall be deducted at platform edges that are open to the trainway.

c) The maximum means of egress capacity of platforms, corridors, and ramps shall be computed at 0.082 0 people/mm-min.

d) The maximum means of egress travel speed along platforms, corridors, and ramps shall be computed at 38.0 m/min.

e) The means of egress travel speed for concourses and other areas where a lesser pedestrian density is anticipated shall be computed at 60.0 m/min.

J-5.4.4 Stairways

a) Unenclosed stairs and escalators shall be permitted to be counted as contributing to the means of egress capacity in stations.

b) Minimum widths of such unenclosed staircases shall be 1 800 mm for unidirectional stairs, and 2 400 mm for bidirectional stairs.

c) Wall or floor mounted railings on both sides shall be permitted on stairs without affecting the widths stated in (b) above by more than 300 mm.

d) Enclosed stairs in the means of egress shall be minimum 1 200 mm wide.

e) Capacity and travel speed for stairs shall be computed at 0.055 5 people/mm-min and 14.6 m/min, respectively.

a) Escalators shall not account for more than one-half of the means of egress capacity at any one level.

b) In calculating the egress capacity of escalators,

1. one escalator at each level shall be considered as being out of service, and

2. the escalator chosen shall be the one having the most adverse effect upon egress capacity.

c) Where escalators are permitted as a means of egress in stations, the following criteria shall be complied with:

1. The escalators shall be constructed of non-combustible materials (exceptions like rollers and handrails shall be permitted with the approval of the Competent Authority).

2. Escalators running in the direction of egress shall be permitted to remain operating.

3. Escalators running reverse to the direction of egress shall be capable of being stopped either locally by a manual stopping device at the escalator or remotely by a manual stopping device at a remote location or remotely as part of a pre-planned evacuation response. A stopped escalator shall be counted as equivalent to 1 m wide staircase.

d) Where provision is made for remote stopping of escalators counted as means of egress, one of the following shall apply:

The stop shall be delayed until it is preceded by a minimum 15 s audible signal or warning message sounded at the escalator; wherein (1) the signal or message shall have a sound intensity that is at least 15 dBA above the average ambient sound level for the entire length of the escalator, (2) the signal shall be

distinct from the fire alarm signal, and (3) the warning message shall meet audibility and intelligibility requirements.

Where escalators are equipped with the necessary controls to decelerate in a controlled manner under the full rated load, the stop shall be delayed for at least 5 s before beginning deceleration, and the deceleration rate shall be no greater than $0.052 \, m/s^{2}$ .

e) Escalators with or without intermediate landings shall be acceptable as a means of egress, regardless of vertical rise.

f) Escalators exposed to the outdoor environment shall be provided with slip-resistant landing and floor plates.

g) Stopped escalators shall be permitted to be started in the direction of egress in accordance with the requirements for stopping of escalators described in J-5.4.5(c)(3) and J-5.4.5(d).

h) Capacity and travel speed for escalators shall be computed at 120 people/min and 18.5 m/min (vertical component of travel speed), respectively.

J-5.4.6 Lifts

Lifts meeting the following requirements shall be counted as one of the means of egress in stations.

J-5.4.6.1 Capacity of lifts

Where lifts are counted as contributing to the means of egress capacity,

a) lifts shall have minimum 60 min fire resistance rating;

b) they shall account for no more than 50 percent of the required egress capacity;

c) at least one lift shall be considered out of service, and one lift shall be reserved for fire service; and

d) the capacity of each lift shall be the carrying capacity of the lifts within $30\mathrm{min}$.

Lifts counted as one of the means of egress from any level of a station shall be accessed through holding areas or lobbies at that level, which shall be designed as follows:

a) The holding areas or lobbies shall be separated from the platform by a smoke tight fire separation having a fire resistance rating of at least 60 min but not less than the time required to evacuate the holding area occupant load.

b) At least one stair shall be accessible from the holding area.

c) The holding area shall be sized to accommodate one person per $0.2\mathrm{m}^2$.

d) If the holding area includes portions of the platform, the area within 600 mm of the trainway shall not be considered in the calculation.

e) Upon activation of smoke control in the platform or adjacent trainway areas, the holding area shall be pressurized to a minimum of 25 Pa.

f) The holding area shall be provided with emergency voice alarm devices with two-way communication to the system operations control centre.

Lifts counted as one of the means of egress shall be designed as follows:

a) Shaft enclosures shall be constructed as fire separations having a $120\mathrm{min}$ fire resistance rating.

b) The design shall limit water flow into the shaft.

c) No more than two lifts used for means of egress or fire department access shall share the same machine room or lifts pit.

d) Machine rooms shall be separated from each other by fire separation having a minimum fire resistance rating of 120 min.

e) The lifts shall be connected to back-up power supply.

f) During emergency evacuation, the lifts shall travel only between the incident level and a point of safety.

J-5.4.7 Doors and Gates

The egress capacity for doors and gates in a means of egress serving public areas shall be computed as,

a) 60 people per minute (p/min) for single leaf doors and gates,

b) 0.082 people/mm-min for bi-parting multi-leaf doors and gates measured for the clear width dimension, and

c) gates in a means of egress shall be designed in accordance with the requirements for doors serving as a means of egress.

a) Fare barriers complying with following provisions shall be permitted in the means of egress serving the stations. Such barriers shall be designed to release, permitting unimpeded

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travel in the direction of egress under all the following conditions:

1. Power failure or ground fault condition,

2. Activation of the station fire alarm signal, and

3. Manual activation from a switch in a constantly attended location in the station or operations control centre.

b) Fare barriers that do not comply with the requirements of J-5.4.8(a) shall be permitted in the means of egress where barriers in the equipment are designed to provide egress when a horizontal force not exceeding 66 N is applied in the egress direction.

c) Gate-type fare barriers in the means of egress shall meet the following criteria:

1. Each unit shall provide a minimum of 450 mm clear width at and below a height of 1 000 mm and 530 mm clear width above that height.

2. Each unit shall be credited with a capacity of $50\mathrm{p / min}$ for egress calculations.

3. Fare barriers shall be designed so that their failure to operate properly will not prohibit movement of passengers in the direction of emergency egress.

Horizontal exits shall be permitted for up to 100 percent of the number of horizontal exits and required egress capacity provided that not more than 50 percent of the number and required capacity is into a single building and provided they comply with the following provisions:

a) Width of the horizontal exit shall at least be same as that of the exit doorways;

b) A horizontal exit shall be equipped with at least one fire/smoke door of minimum 60 min fire resistance, of self-closing type. Further, it should have direct connectivity to the egress staircase for evacuation.

c) Where there is a difference in level between connected areas for horizontal exits, ramps, slope not more than 1 in 12 shall be provided.

d) Doors in horizontal exits shall be able to open at all times from both sides.

J-5.4.10 Platform Screen and Edge Door

Horizontal sliding platform screen or platform edge doors shall be permitted to separate the platform from the trainway in stations provided that the doors permit emergency egress from the train to the platform regardless of the stopping position of the train; and the doors provide egress when a force not exceeding 220 N

is applied from the train side of the doors. The doors shall be designed to withstand positive and negative pressures caused by passing trains.

A dedicated access staircase for firemen shall be provided in each underground station. This access shall be arranged so as to provide uninterrupted access from ground level to station concourse and platform levels. If continuous access is not feasible, smoke sealed lobbies shall be provided at concourse or other intermediate levels and such lobbies shall be protected with fire doors of adequate rating. Firemen staircases shall be maintained under positive pressure at all times.

J-5.4.12 Emergency and escape lighting and illumination of means of all exits shall comply with the various provisions under 3.4.7 in all respects.