The provisions of this chapter shall serve to express the intentions for determining the design, construction, protection, location, arrangement and maintenance of exit facilities to provide safe means of escape for occupants from all buildings hereafter erected, altered or changed in occupancy. Areas which are designated as means of escape, such as exit staircase, fire lift lobby, smoke-free lobby, exit passageway, escape corridor shall not be turned into other usage.
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Document Version: 2023
Fire Code
2
Means of Escape
2.1
General
2.2
Determination of Exit Requirements
2.2.1
General
The determination of exit requirements for a building shall be based upon the type of use or occupancy of the building, the occupant load, the floor area, the travel distance to an exit and the capacity of exits as provided in Table 2.2A and herein. Every storey of a building shall be provided with exit facilities for its occupant load. Vertical exits provided from any storey above ground level may serve simultaneously all storeys above the ground level. Vertical exits provided from any storey below ground level may serve all storeys below ground level, subject to the provisions of Cl.2.3.5 which prohibit basement staircases being continuous with exit staircases serving the upper storeys, unless otherwise allowed by the SCDF.
Explanations & Illustrations
DETERMINING NUMBER AND ADEQUACY OF EXIT FACILITIES
It is very essential that the building designers establish the number, sizes and capacity of exit facilities, especially that of exit doorways and exit staircases, to ensure their adequacy in facilitating the evacuation of all the occupants from that building during an emergency.
To determine the number and adequacy of exit doorways and staircases from a building or storey of a building, the following 3 steps must be taken:
Determine the occupant load, OL, on each storey of the building. This means computing the total number of persons that could be ‘accommodated’ in all spaces on a storey of the building. This is done on a storey by storey basis.
Determine the number of ‘unit of width’ of exit required facilitating escape for the above OL from each storey of that building. Cl.2.2.5 shall be referred for the explanation and application of the ‘unit of width’ for exit computation.
Determine the number of and the minimum widths of the exit doors and exit staircases required facilitating escape for that OL on each storey of that building.
Rationale
The exit provisions allow occupants to leave the fire area safely in the shortest possible time to a safe area.
2.2.2
Mixed occupancy
Where different parts of a building or storey of a building are designed for different types of occupancies or used for different purposes at the same time, the exit requirements of the entire building or storey of the building shall be determined on the basis of that type of occupancy or usage having the strictest exit requirements or the exit requirements for each building section shall be determined separately.
Explanations & Illustrations
MIXED OCCUPANCY - OFFICES, FACTORIES & WAREHOUSES
TRAVEL DISTANCE REQUIREMENT:-
For a storey of mixed occupancy building consisting of offices, factories and warehouses, the exit capacity of staircases may be based on the total of the occupancies computed separately for each usage type as per Table 1.4B. However the position of the exit staircases shall be so located that the maximum permissible travel distance from any remote point to the staircase shall be based on that of the factory, having the stricter requirements in Table 2.2A. That is, equal to 30m for two-way non-sprinkler-protected buildings and 60m for two-way sprinkler protected buildings, and not the 45m and 75m distances allowable for office developments. Hence:
Travel distance (in Figure 2.2.2-1) to the nearest exit staircase shall not exceed 30m or 60m (if sprinkler-protected).
The Direct distance to the nearest exit staircase, if there are no predetermined walls, shall not exceed 20m (2/3 x 30m) or 40m (2/3 x 60m, if sprinkler-protected).
The exit provisions in a mixed development may be assessed and provided separately if the differing purpose types are clearly defined and compartmentalized. For example, the escape distances for the offices’ area which is clearly located in one part of the building as shown in Figure 2.2.2 – 2, may be based on the office configurations given in Table 2.2A. The remaining part of the building with the industrial usage is then based on the factory configurations.
EXIT REQUIREMENT:-
Buildings with mixed occupancies the exit capacity of its exit staircases shall be based on the type of occupancy or usage having the strictest exit requirements given in Table 2.2A.
For example;
A storey of a building comprises dormitory, production and offices separated by usage with compartment walls, but shares common facilities like the staircases.
Then the exit capacity of its staircases shall be based on:
Dormitory occupancy which the number of persons per unit of exit width (500mm) of staircase is 45 persons.
Instead of:
Factory / Office / Warehouse occupancies which the number of persons per unit of exit width (500mm) of staircase is 60 persons.
The maximum permissible occupant load (OL) for the entire storey of the building in Figure 2.2.2 - 3, for example, shall be based on the capacity of the two exit staircases of 2m width each, assumed serving a dormitory building. i.e.
OL = 4 units x 45 persons x 2 staircases
= 360 persons (maximum per storey)
Figure 2.2.2 - 4 : Building with mixed occupancy
Figure 2.2.2 - 5 : Building with mixed occupancy
This capacity of staircase exit width shall be applicable for all levels or storeys of the building with such shared staircase arrangement. This is regardless of the dormitory being located on the second storey or the top most storey of a multi-storey building. The only exemption is when the space with the more stringent requirement per unit of exit width, e.g. the dormitory, is located on only the ground level storey with direct escape to the external space.
(1) Travel distance requirement:
For a storey of mixed occupancy building consisting of offices, shops and place of public resort, the exit capacity of staircases may be based on the total of the occupancies computed separately for each usage type as per Table 1.4B . However the position of the exit staircases shall be so located that the maximum permissible travel distance from any remote point to the staircase shall be based on that of the shop, having the stricter requirements in Table 2.2A. That is, maximum 45m two-way escape travel distance for non-sprinkler-protected buildings and 60m two-way escape travel distance for sprinkler protected buildings shall be applicable and not the 45m and 75m distances allowable for office developments. Hence:
Travel distance (in Figure 2.2.2 - 1) to the nearest exit staircase shall not exceed 30m or 60m (if sprinkler-protected).
The direct distance to the nearest exit staircase, if there are no predetermined walls, shall not exceed 30m (2/3 x 45m) or 40m (2/3 x 60m, if sprinkler-protected).
MIXED OCCUPANCY - OFFICES, SHOPS & PLACES OF PUBLIC RESORT
TRAVEL DISTANCE REQUIREMENT:
For a storey of mixed occupancy building consisting of offices, shops and place of public resort, the exit capacity of staircases may be based on the total of the occupancies computed separately for each usage type as per Table 1.4B . However the position of the exit staircases shall be so located that the maximum permissible travel distance from any remote point to the staircase shall be based on that of the shop, having the stricter requirements in Table 2.2A. That is, maximum 45m two-way escape travel distance for non-sprinkler-protected buildings and 60m two-way escape travel distance for sprinkler-protected buildings shall be applicable and not the 45m and 75m distances allowable for office developments. Hence:
Travel distance (in Diagram 2.2.2-1) to the nearest exit staircase shall not exceed 30m or 60m (if sprinkler-protected).
The direct distance to the nearest exit staircase, if there are no predetermined walls, shall not exceed 30m (2/3 x 45m) or 40m (2/3 x 60m, if sprinkler-protected).
The exit provisions in a mixed development may be assessed and provided separately if the differing purpose types are clearly defined and compartmentalised.
For example, the escape distances for the offices’ area, which is clearly located in one part of the building as shown in Figure 2.2.2 - 6, may be based on the office configurations given in Table 2.2A . The remaining part of the building with the shopping usage is then based on the shop configurations.
EXIT REQUIREMENT:
Buildings with mixed occupancies the exit capacity of its exit staircases shall be based on the type of occupancy or usage having the strictest exit requirements given in Table 2.2A.
For example, see Figure 2.2.2 - 3
A storey of a building comprises office and hotel residential occupancy separated by compartment walls, but shares common facilities like the staircases and lifts.
Then the exit capacity of its shared staircase (staircase S2) shall be based on the most stringent type of mixed occupancies, i.e. hotel residential floors.
Office Occupancy (Staircase S1)
No. of persons per unit of exit width (500mm) of staircase = 60 persons.
Hotel Residential Occupancy (Staircase S2 & S3)
No. of persons per unit of exit width (500mm) of staircase = 45 persons.
In the case of restaurant, the maximum permissible occupant load can be based on the capacity of the three staircases. As Staircase S3 is for the exclusive use of restaurant, owing to its location, this staircase is inaccessible to occupants from offices and shops. Therefore, Staircase S3 shall not be computed as a common exit staircase rather computed as exit staircase for restaurant only. That is:
Exit capacity of common staircases = 4 units x 60 persons x 2 staircases
(Staircases S1 & S2 of 2m width each) = 480 persons
Hence, each common exit staircase can accommodate 240 persons (½ of 480 persons)
It is acceptable to allow ½ the occupant load of restaurant to use Staircase S3 and the other ½ to use the common exit staircases S1 & S2. Therefore, the maximum permissible occupant load for shops and offices shall include ½ the occupant load of restaurant, subject to not exceeding a total of 480 persons.
Figure 2.2.2 - 10 : Situation where the exit capacities of entire staircase on all storeys are accounted similarly
The strictest capacity of staircase exit width (applicable to restaurant) shall be applicable to all levels or storeys of the building with such shared staircase arrangement. This is regardless of the restaurant being located on the second storey or the top most storey of a multi-storey building.
Auditorium space shares the internal corridor as the classrooms. Such space cannot be qualified as non-simultaneous occupancy within the same storey.
2.2.3
Multiple occupancy or use
Where a building or storey of a building or a part of a building is used for multiple purposes involving different activities at different times, that purpose or use involving the greatest number of occupants shall form the basis for determining the exit requirements.
Explanations & Illustrations
A multi-purpose hall is an example of a space with multiple occupancy or use. It may have the various uses as listed below. Its exit provisions shall be based on the usage with the greatest occupant load. In this case it should cater to that of the dance hall, being the most stringent basing on an area of 1m2 per person.
Examples of usage of multipurpose hall:
Sports gym
Dinner/buffet functions
Exhibitions/seminars
Church assembly
Lecture hall/classroom
Dance hall
Figure 2.2.3 - 1 : Example of building with a multiple usage storey
Figure 2.2.3 - 2 : Example of building with a multiple usage storey
In Diagram 2.2.3-1, the multi-purpose hall located on the 7th storey would have the highest occupant load. Hence, adequate number of exit staircases required to accommodate the evacuation of its occupant load shall be provided to the building. The total exit capacity of its exit staircases shall be determined based on its usage with the highest density of people. The exit staircases shall be carried right down to the ground level without any reduction in its width, regardless of the lower storeys having lesser number of occupants.
On the other hand, if the multi-purpose hall is located on an intermediate storey, then the exit requirements or provisions from that storey shall only be applicable to all the storeys below it. As for those storeys above that storey with the multipurpose hall, their exit capacities need only cater to what is the strictest above each respective storey.
2.2.4
Non-simultaneous occupancy
The floor areas of toilets, locker rooms, lobbies, and corridors that are not occupied at the same time as other rooms or spaces by building occupants, can be omitted from the occupant load calculations of that storey of the building in which the storey is located.
Explanations & Illustrations
Communal roof deck which is accessible to all residents shall be treated separately for the calculation of occupant load. For buildings under PG II, the occupancy load calculation is based on gross floor area of 15m2 per person, calculated on habitable areas. Spaces outside the residential units, such as lobbies, corridors would be excluded from calculation. Similarly, within the residential units, areas such as toilets, store room, kitchen and household shelter would be excluded from calculation. Living room, balconies and bedroom should be treated as habitable areas.
Staff canteens, if provided, is to be treated as simultaneous occupancies. This is due to the nature of its usage, whereby public or staff from other levels of the building would be patronising it through its operating hours. Pantries on the other hand, provided in the various levels of offices or production areas, catering to specific group of staff, may be treated as non-simultaneous areas. Hence, in applying the above clause, building owners has to be certain such rooms or spaces are not accessible to the public.
2.2.5
Capacity of exits and exit facilities
The capacity of exits, exit staircases, exit passageways, corridors, exit doors and other exit facilities shall be measured in units of half a metre's width. The number of persons per unit of width shall be determined by the type of occupancy and type of exit as listed under Table 2.2A. In the determination of each exit width, fractions of a unit width less than 250mm shall not be factored in the measurement. Where 250mm or more are added to one or more full units, half of a unit of width shall be factored in.
Where a room or space is required to be provided with two exits, each exit shall be of sufficient width to accommodate not less than half the total occupant load.
Explanations & Illustrations
To prevent overcrowding one has to ensure that the corridor and the exit staircases serving a storey of a building are adequate in size to receive all the occupants on that floor at the time of evacuation.
The capacity of exit doors to the industrial units, corridor, exit doors to staircases and exit staircases are measured in units of width of one half of a metre i.e.:
Exit door/corridor/staircase clear width | Number of unit width |
|---|---|
1m | 2 |
1.5m | 3 |
2m | 4 |
Where a fraction of 250mm or more are added to one or more full units, half of a unit of width shall be credited, for example:
Exit door/corridor/staircase clear width | Number of unit width |
|---|---|
1000 to 1249mm | 2 |
1250 to 1499mm | 2.5 |
1500 to 1749mm | 3 |
1750 to 1999mm | 3.5 |
2000mm (maximum) | 4 (maximum number per exit) |
The number of persons per unit of width shall be determined by the type of occupancy and type of exit as listed under Table 2.2A of the current Fire Code.
Example 1 : High hazard building
1 unit width = 500mm = 30 and 40 persons per unit width through staircase and doorway respectively.
Therefore: 1m doorway facilitates escape for 80 occupants from a high hazard factory, while 1m of its stairway permits escape for only 60 of its occupants.
The high hazard building has very much more stringent requirements than other buildings. It is due to the nature of its contents. In an emergency situation, because of the highly volatile or explosive nature of the contents, its occupants have very little reaction time to evacuate to a safer area. Hence, exits must be designed such that they are more readily available for escape purposes.
Where a room or space is required to be provided with two exits, each exit shall be of sufficient width to accommodate not less than one half the total occupant load.
The above sub-clause is to address the problem, which may arise if staircases are not proportionately sized and distributed. For example, a fire near Stair A in Diagram 2.2.5 –3, which is designed to facilitate escape for 240 persons, can render it inaccessible. This would mean that, the other exit, stair B, which is only designed for 120 persons’ escape, would hence need to facilitate escape for the full OL of 360 persons from that storey.
This scenario would render stair B to be drastically inadequate to facilitate all the occupants’ timely escape, before the fire and smoke engulf the entire floor space. This is because it would require three times as long to evacuate the occupants from that storey using only stair B.
Imagine the consequences, for a scenario where the entire staircase A with the larger exit capacity is totally damaged or not usable in a high-rise building fire.
Rationale
Adhering to the design parameters will prevent overcrowding and will ensure the corridors, exit staircases and doors are adequate in size to receive all the occupants on that floor during evacuation.
2.2.6
Determination of travel distance
The maximum travel distance for the respective types of occupancies shall be not greater than as laid down in Table 2.2A and read in conjunction with all of the following:
In the case of a floor area designed with minimum two exits, the maximum travel distance as given in Table 2.2A shall be applicable. The maximum travel distance starting from the most remote point in any occupied space to the nearest exit, shall not exceed the limits specified in Table 2.2A.
In a large floor area without sub-division of rooms, corridors and so forth, the travel distance can adopt the “direct distance” concept as a guide and shall not exceed two-third of the maximum travel distance permitted under Table 2.2A. Where the large floor area is undergoing sub-division of rooms, corridors, etc., the maximum travel distance shall be in accordance with Table 2.2A.
For the purpose of this clause, the most remote point from which the travel distance is measured shall be taken as being 400mm from the enclosure walls of the room or space.
In the case of a residential apartment or maisonette, the travel distance shall be determined based on the provisions under Cl.9.2.1a.(5).
Where area of refuge is provided in lieu of required exits, travel distance shall be measured to the exit door at the corridor leading to the area of refuge.
Where permitted under Cl.2.3.3 for exit staircases not required to be protected with fire-rated enclosures or to be entered without the provision of an exit door, the travel distance shall be measured to the exit doors at ground level or measured to a position where the exit door would be installed if otherwise required, respectively.
Ancillary office within other purpose groups
Where an ancillary office is housed within a space belong to other Purpose Groups, the travel distance requirement for the ancillary office is allowed to be based on PG IV, provided:
the ancillary office is fire compartmented from spaces belonging to the other purpose groups; and
the ancillary office occupants shall have access to exit(s) within the ancillary office compartment leading to direct discharge at ground level into an external space, exit staircase, or internal/ external exit passageway
Explanations & Illustrations
Clause 2.2.6a. : Determination of travel distance
In the above figures, the exit staircases are not remotely located from each other to reduce the possibility that more than one staircase can be blocked off by fire or other emergency condition. The escape routes AB, CD, EF, and GH are all considered as one-way direct travel as there is no alternative escape route. Occupants escaping in a fire emergency are unable to reach the nearest staircase as the escape routes are blocked by fire. The distribution of the staircases does not meet the intents of Cl.2.3.12 of current Fire Code, which require that “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 fire or other emergency condition”.
In the above figures, direct travel distances, which are highlighted, will be considered as one-way direct travel instead of two-way direct distance travel. To overcome the problems of one-way direct travel, relocation or addition of an exit staircase would be necessary, subject to meeting the direct travel distance requirements.
Clause 2.2.6b. :Determination of travel distance
Similarly, if the details of the internal layout are furnished on the building plan submissions, hence the actual travel distances permissible under the Table 2.2A would be taken into account.
However, in most situations during the planning and building plan submission stages of a building, its designer is unable to confirm the layout of the storey spaces. It is therefore recommended that the direct distance measurements, which are two thirds of the allowable travel distances, be strictly applied to such ‘open’ plans.
Example
The dotted walls in Figure 2.2.6(b) - 1, for example, may not be shown on plan and/or may be of differing configurations. In such indefinite situation, a straight line drawn from the most remote point A to B or C shall be taken as the two-way direct distance. If the maximum permissible two-way travel distance given in Table 2.2A for such usage is 60m (sprinkler-protected), then the direct distances (straight lines AB or AC) shall not exceed 40m, i.e. ⅔ x 60m. This shall also apply to the one-way distances BD and CF, as the actual one-way distances could possibly be D1HB and F1JC.
This application of the direct distance measurements, besides facilitating flexibility for future inclusions and changes in layout, ensures that escape distances for the occupants would not subsequently be excessive and life threatening in a fire emergency.
(Note: “travel distance” is to be taken as direct distance).
Maximum escape distance design parameters
Item | Sprinklered | Non-sprinklered | ||||
|---|---|---|---|---|---|---|
Shops | Offices | Places of public resort | Shops | Offices | Places of public resort | |
1-way Travel Distance (m) | 25 | 30 | 25 | 15 | 15 | 15 |
1-way Direct Distance (m) | 16.6 | 20 | 16.6 | 10 | 10 | 10 |
2-way Travel Distance (m) | 60 | 75 | 60 | 45 | 45 | 45 |
2-way Direct Distance (m) | 40 | 50 | 40 | 30 | 30 | 30 |
DIRECT DISTANCE = ⅔ TRAVEL DISTANCE
The actual path that an occupant needs to take from any part of a storey space to the nearest exit door to the external space or exit staircase, will be measured for escape travel distance compliance. This distance takes into account the internal partitions within that floor space and it shall comply with the relevant travel distances stipulated in Table 2.2A.
Thus, where details of the internal layout are furnished in the building plan submissions, for example Figure 2.2.6 (a) & (b) – 1, the full travel distances permissible under the Table 2.2A would be applied.
However, in most situations during the planning and building plan submission stages of a building, the designer is unable to confirm the internal layout of the storey spaces. It is recommended that the direct distance measurement, which is two thirds of the allowable travel distances, should be applied to such ‘open’ layout plans.
Example
A to B is considered as one-way travel distance and it shall be not more than 25m (sprinkler-protected). In computing two-way travel distance, the escape route from point A, B, C shall not exceed 60m (sprinkler-protected)
Point A to C and Point A to B are considered two-way travel distance if the separation distance between exit doors of the two staircases is equal to or more than ½D or ⅓D (sprinkler-protected). If the storey space is to be subdivided for occupation by more than one occupier, a common corridor around the service core shall be created to meet the travel distance requirements.
Escape routes AB, AC are considered two-way direct travel. Escape routes DE, FG are considered one-way direct travel distances.
The numerous one-way direct travel distances are illustrated by dashed lines.
The provision of fixed corridors and rooms in an open floor space would create numerous “common paths” from the rooms to the exit staircases as shown in the above figure. Common paths of travel are one-direction travel only without the choice of travelling in another separate direction toward an exit.
In determining the types of travel distance, Point A, B or C is considered one-way travel distance or “common path”. At point C, where an occupant has the choice of more than one escape direction, would be considered as the starting point for 2-way travel distance. Hence, escape routes C E and C D are considered two-way travel distance.
Escape routes AB, AC are considered two-way direct travel. Escape routes DE, FG are considered one-way direct travel distances.
Clause 2.2.6c. : Determination of travel distance
Figure 2.2.6c.
Clause 2.2.6e. : Determination of travel distance
Where an area is designated as ‘area of refuge’ (Building B in Figure 2.2.6e., it must have adequate provision of exit facility and shall be adequate in size to hold the occupant load it receives from the floor area (Building A) it serves, allowing at least 0.3m² per person. Area of refuge acts as a temporary holding area allowing the occupants more time for evacuation. Hence, it shall be protected from the fire and smoke risk from building A via the provision of cross-ventilated bridges or external corridors.
Reference shall also be made to Cl.1.4.9 and Cl.2.2.15 for more explanations and details on the area of refuge.
of the same building connected through a linkway/bridge
Where an area is designated as ‘area of refuge’ (Building B in Figure 2.2.6e. – 1 & 2), it must be adequate in size to hold the occupant load it receive from the floor area (Building A) which it serves as area of refuge. Area of refuge acts as a temporary holding area allowing the occupants more time for evacuation. Hence, it shall be protected from the fire and smoke risk from Building A via the provision of cross-ventilated bridges or external corridors.
While some conditions for the area of refuge is given below, reference shall also be made to Cl.1.4.9 and Cl.2.2.15 for more explanations and details on the area of refuge.
connected through a linkway/bridge
Lines EA and ED are taken as two-way direct distance measurements.
General conditions for area of refuge
Occupant Load for area of refuge to be based on 0.3m2 per person.
Each connecting area shall have at least one protected staircase or exit facility of adequate width discharging at ground level.
Access door to area of refuge shall be kept accessible at all times
Door No 1, {in Figure 2.2.6e. – 2} leading to area of refuge can also be treated as a required exit from the area served by it, and hence travel distance can also be measured to this door.
General conditions for area of refuge
Area of Refuge shall be adequate in size to hold the occupant load it receives from Building A, in addition to its own occupant load calculated on the basis 0.3m2 per person.
Each connecting area or floor served by an area of refuge shall have at least one protected staircase or exit facility of adequate width discharging at ground level.
Access door to area of refuge shall be kept accessible at all times.
Door D & E, {in Figure 2.2.6e. – 2 & 3 respectively} leading to area of refuge can also be treated as a required exit from the area served by it, and hence travel distance can also be measured to these doors.
Clause 2.2.6f. : Determination of travel distance
Clause 2.2.6g. : Determination of travel distance
The fire risk in office space is lower than factory space. If there is fire separation between office and factory spaces as shown above, the travel distance requirement for the ancillary office is allowed to be based on office use under PG IV.
Rationale
Clause 2.2.6a
The travel distance serves to limit the distance a person is required to travel from the occupied space to an exit staircase door, which every designer should observe. On the other hands, it must also be stated that conforming to the permissible travel distance alone does not necessarily guarantee building occupant life safety during an emergency.
Clause 2.2.6b
The two-third direct distance method is intended to guide designer for planning of large open floor layout for facilitating flexibility for future inclusions and changes in layout. This guide serves to minimise problem of complying with travel distance during subsequent A/A works.
2.2.7
Minimum width of exit access door, exit door or other exit facilities
No exit, exit staircase or other exit facilities shall be narrower than the minimum width requirement as specified under Table 2.2A. The minimum clear width of an exit door/ exit access opening shall be not less than 850mm.
Exit access doors serving a room with an occupant load of not more than two persons shall not be less than 610mm in clear width.
A single leaf swing door along the means of egress shall not exceed 1.25m in clear width.
Explanations & Illustrations
Clause 2.2.7a. : Minimum width of exit access door, exit door or other exit facilities
Figure 2.2.7a. - 1
Other exit facilities refer to passageways, defined corridors, etc.
In the case of PG I dwelling unit, the minimum width of corridor and access staircase is 900mm. This relaxation is not applicable to all other purpose group buildings.
Clear width of exit door opening shall not be less than 850mm. It shall be measured clear of any protrusion except doorknob or lockset, subject to complying with exit requirements. 850mm is equivalent to 1½ units of width only, for the purpose of determining the exit capacity.
Clear width of corridor leading to an exit shall not be less than 1200m.
Figure 2.2.7a. - 6.
Figure 2.2.7a. - 7
Clear width of exit staircase shall not be less than 1000mm. Please refer to Cl.2.2.9a. for details on measuring of width.
Clear width of internal access staircase in maisonnette unit can be less than 1m but not less than 900mm. This relaxation is only permitted for PG I residential building.
Clear width of internal access staircase in factory unit with mezzanine level office shall not be less than 1000mm. The one-way travel distance from the most remote point of the ancillary office on mezzanine level to the exit door on the main storey level of factory shall not exceed the permissible limits of Table 2.2A.
Rationale
Clause 2.2.7c
The purpose of controlling the width of single leaf door is to discourage the use of bigger, heavier leaf doors. This is because there is risk of door sagging and thus require more effort to open the door. To overcome it, 2-leaf doors should be used in larger openings instead of single leaf swing door.
2.2.8
Maximum width of exit staircases
The maximum width of exit staircases shall be not more than 2m. Where staircases exceed 2m in width, handrails shall be used to divide the staircase into sections of width not less than 1m or more than 2m.
For the purpose of determining the exit capacity of a staircase that is wider than 2m that forms part of the required means of escape from any storey of the building, that part of its width in excess of 2m shall not be taken into account.
Explanations & Illustrations
The above sub clause does not preclude the design of staircases wider then 2000mm. It is intended to limit the number of occupants to be allocated to a single exit staircase, and thereby, prevent the concentration of the occupant’s escape at any one point of exit. The consequences, if higher capacity is to be permitted through an exit without capping would be disastrous, if that staircase is to be rendered unusable, in an emergency situation.
Hence, where a staircase is designed with a width greater than 2000mm, its total exit capacity shall be based on the capacity of only 4 units of exit width when determining the adequacy of exit provisions from that storey of building served by that staircase.
This staircase is also required to be sub-divided equally into 2 or more sections with handrails such that the spacing between the handrails are not less than 1000mm and not more than 2000mm.
Figure 2.2.8 - 2
Figure 2.2.8 - 3
The width of staircase of 2500mm is being divided into 2 sections of 1250mm each by the introduction of an intermediate handrail. Although the staircase is 2500mm clear, it is still computed as 2000mm only. Dividing staircase wider than 2000mm enables better crowd control and orderly evacuation in times of emergency.
Rationale
The purpose of limiting the maximum effective exit capacity of an exit staircase is to prevent concentration of evacuees at any point of the exit. The consequence of permitting exit staircase without capacity limits could be disastrous if that staircase were rendered unusable in an emergency situation. Dividing staircase into segments not wider than 2m enables better crowd control and orderly evacuation in times of emergency.
2.2.9
Measurement of width
The measurement of width referred to under Cl.2.2.7 and Cl.2.2.8 shall be the clear width, including the width of plinth to balustrade or parapet wall:
For an exit staircase
The clear width shall be measured between:
the finished surfaces of the walls, if the staircase is enclosed on both sides by walls only, or
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
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.
For an exit door
In the case of an exit 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 2.2.9b..
In the case of a 2 leaf exit 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°.
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°.
Door hardware and handrails which do not protrude more than 80mm into the clear width of exit opening can be disregarded.
Explanations & Illustrations
Clause 2.2.9a.(1) : Measurement of width
Clause 2.2.9a.(2) : Measurement of width
Figure 2.2.9a.(2) - 2
Clause 2.2.9a.(3) : Measurement of width
Figure 2.2.9a.(3) - 2
If the projection of handrail exceeds 80mm, the clear width shall be measured between the inner sides of the handrails.
Clause 2.2.9b. : Measurement of width
The terminology “2-leaf” is generally known as “multi-leaf” a common term in the building industry. It may comprise of leaf door panels of different sizes. The smaller leaf door may be bolted onto the floor and opened only to facilitate shifting of bulky items. The smaller leaf door if intended to be kept in closed position and not use as escape, it need not be provided with door closer.
Determining the egress width of swinging doors for purposes of calculating capacity, only the clear width of the doorway when the door is open 90 degrees shall be measured. In determining the egress width for other types of doors for purposes of calculating capacity, only the clear width of the doorway when the door is in the full open position shall be measured. Clear width of doorways shall be measured between the face of the door and door frame.
Rationale
The allowance of 80mm projection of handrail is considered acceptable as the projection would normally occur at the waist-height of a person. Therefore, it is unlikely to affect the egress within a protected staircase.
2.2.10
Number of exits from rooms and spaces
There shall be at least two door openings remote from each other which lead to exits from every room or enclosed space in which the total occupant load exceeds the maximum permissible occupant load for one door as listed in the table below:
TABLE 2.2.10 - PERMISSIBLE OCCUPANT LOAD FOR ONE DOOR | |
|---|---|
Type of Occupancy | Max. Occupant Load |
High hazard | 25 |
Patient accommodation area | 50 |
Classrooms | 50 |
Godowns, stores, and factories not of high hazard type | 50 |
Assembly | 50 |
Note: | |
2.2.11
Number of exit staircases or exits per storey
There shall be at least two independent exit staircases or other exits from every storey of a building, unless otherwise permitted under other subsequent provisions of the Code.
Exception
For non-habitable roof that is able to comply with one-way travel distance, at least one exit staircase shall be provided. The travel distances for roof areas which are open-to-sky shall be based on the requirements for sprinkler-protected buildings.
For non-habitable roof that is unable to comply with one-way travel distance to the exit staircase, an additional cat/ ship ladder adequately separated in accordance with Cl.2.3.12 and leading to the circulation area of the floor below shall be provided. All access hatches, if provided, shall be readily accessible from the roof. Access hatch opening shall have a minimum clear width of 1m in diameter. The travel distances for roof areas which are open-to-sky shall be based on the requirements for sprinkler-protected buildings.
Roof of the protruding structures above the non-habitable roof, namely exit staircase shafts and lift motor rooms.
For green roofs which are accessible for maintenance purposes only, the means of access shall comply with Cl.10.2.1b.(1)(a).
Explanations & Illustrations
Minimum requirement – 2 exit staircases per storey
Single exit is permissible if the storey of the building can satisfy the conditions stipulated in Cl.2.2.10 and Cl.2.6.
Single staircase provision is permitted for residential buildings under Cl.9.2.1a.(3), Cl.9.2.1a.(4) and commercial/industrial buildings under Cl.9.4.1a., 9.5.1a., 9.6.1a. or, 9.8.1a..
Rationale
Where possible, occupants should not be denied of alternate egress to an exit staircase. By having minimum two exit staircases, it provides an alternative for occupants to access either. This clause also addresses exit provision for non-habitable roofs and incorporates fixed ladder and access hatches requirements.
2.2.12
Location of exits & access to exits
All exits and access facilities shall be required to comply with all of the following:
Exits and access facilities shall be clearly visible or their locations shall be clearly indicated and shall be kept readily accessible and unobstructed at all times.
Every occupant within a building or storey of a building shall have direct access to the required exit or exits without the need to pass through another room(s) or other tenanted space(s). Where direct access to the required exit or exits of the storey is not possible, occupants shall only be allowed to pass through a maximum of one other room or space belonging to the same tenant with the following conditions being complied with:
the exit access door separating the rooms or spaces which the egress route passes through shall only be fitted with electromechanical device designed in accordance with Cl.2.3.9k.(2);
the doorway of the exit access door shall not be blocked/obstructed and be kept clear at all times.
warning signs of wording “Exit Access Door - Keep Clear” shall be placed prominently on both sides of the exit access door, and
the egress paths through the exit access door shall be suitably demarcated.
When more than one exit is required from any room or space or a storey of a building, each exit shall be placed as remote as possible from the other as permitted under Cl.2.3.12a., b., c. or d..
Explanations & Illustrations
Clause 2.2.12b. : Location of exits & access to exits
Where any storey of a building is occupied by more than one tenant, it is imperative that each occupant from any of the tenancies shall have direct accessibility to alternate exit staircases without having to enter other tenancies. This could be facilitated via common or neutral spaces like corridors or lobbies that are accessible to all occupants on that storey.
Examples of correct method of determining access travel routes to the required exits:
The above figure shows an incorrect method of determining access travel routes as the paths have to traverse through other tenancies. Though tenants A and C may have adequate exits, tenants B and D will not be able to meet required exit provisions and hence it would not be allowed.
This arrangement of exits for the separate tenancies is not acceptable because the central door, circled in Figure 2.2.12b. – 4, would be kept locked for security reasons and to prevent or avoid any intrusion from one another. This would render the occupants from that storey with insufficient number of exits for escape in an emergency.
Clause 2.2.12c. : Location of exits & access to exits
The distance between the sides of the two exit doors to the scissor staircases A and B shall be equal to or more than one half the length of the maximum overall diagonal dimension (D) of the lobby, or 7m, whichever is greater. Please refer to Cl.2.3.4 as these are conditions for compliance of scissor staircase.
Permanently fixed ventilation openings in the external walls to the lobby shall not be less than 15% of the lobby floor area and located not more than 9m from any part of the lobby (see Cl.2.2.13b.(7)(a) & (b)).
This method of measurement for unit exit door is only applicable to residential buildings.
The distance between the sides of two exit doors to the staircases A and B is less than one half the length of the maximum overall diagonal dimension (D) of the lobby.
Distance between exit door to staircase 1 & 2 shall be at least ½ (or ⅓, if sprinkler-protected) the longest diagonal of the building indicated as (D) in the above figure.
One-way travel distance exists where a space is arranged so that occupants within that space are able to travel in only one direction to reach any of the exits or to reach the point at which the occupants have the choice of two-way travel to remote exits.
For example, the portions of the escape routes from points a to b and e to f are one-way travel, which shall not exceed 15m or 25m (sprinkler-protected). The option to travel in another escape route occurs at points b and f, which provide two-way travel distances to the exit staircases 1 & 2 respectively. One-way travel distances are indicated by the dashed lines. See further illustrations under Cl.2.3.12b., c. or d.
Rationale
Clause 2.2.12c
To reduce the possibility of more than one exit staircase being rendered unusable simultaneously by fire or other emergency situations, the exit staircases are to be remotely located from each other.
2.2.13
Smoke-free approach to exit staircase
Entry at every storey level (including 1st storey) to an exit staircase serving more than four storeys above ground level shall be through any one of the following:
2.2.13a
An external exit passageway or external corridor
The openings for natural ventilation to the corridor shall be located such that they face and are open to any of the following:
an external space complying with Cl.2.3.11, or
a street, service road or other public space which is open to the sky, or
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, except that for external corridors, it shall comply with the requirements of Cl.2.3.10.
Explanations & Illustrations
Figure 2.2.13a. - 2
Figure 2.2.13a. - 3
External exit passageway is a protected area, which is an extension of the vertical exit staircase. It is used to overcome excessive travel distances as shown in the above figure.
The provision of smoke screen above the passageway before the staircase is to prevent smoke from entering the stairwell at ceiling level.
Main differences between external corridor, smoke-stop lobby and external exit passageway
# | External corridor | Smoke-Stop | External exit |
|---|---|---|---|
Entrance door | No fire rating | At least ½-hr | At least ½-hr |
Usage | As smoke-free | As smoke-free | As extension of the vertical exit (to |
Corridor/lobby – air well ventilation | Min 1.2m high Max 3m roof over 1m <parapet wall<1.1m Air well - Min 6m wide / area 93m² | Opening 15% of lobby area Max 9m from opening Air well - min 6m wide / area 93m² | Min 1.2m high Max 3m roofed over 1m<Parapet wall <1.1m Comply with Table 1.2.1A if facing air well |
Cross ventilation | Min 1.2m high Max 3m roof over | Opening 50% of opposing wall superficial area Max 12m from opening No obstruction | Min 1.2m high Max 3m roof over 1m<Parapet wall <1.1m Comply with |
Vent openings btw unit & corridor/smoke-stop lobby | Above 1100mm from finished floor level of corridor | No opening allowed | Above 1800mm from finished floor level of |
Risers | No fire rating for shaft door | Fire rated shaft and doors | No services allowed |
Exposed M&E | Service allowed only if enclosed with fire rated enclosure | No services | No services allowed |
It is important that exit staircases are kept free of any smoke at all times, especially in times of a fire emergency, as it is the main essential means for evacuating occupants from the building. To facilitate this smoke free environment, a buffer zone that can quickly dispel any smoke entering it from occupied spaces to the external space is created before entry into the staircases. Hence the passage or route through these areas (or buffer zone) which is relatively free of smoke for safe escape for the occupants and leading to the exit staircases is referred here as the smoke free approach.
Travel Distance measurement, as shown by line AB in Diagram 2.2.13 (a)(iii)-4, in the external corridor situation is taken from any remote point within the occupied area to the exit door of the exit staircase.
External Exit passageway, as shown in Diagrams 2.2.13 (a) – 2 below, is a protected area, which is an extension of the vertical exit staircase. It is used to overcome excessive travel distances.
A smoke screen may be provided above the passageway before the entry into the exit staircase to prevent smoke at the ceiling level from entering the stairwell.
The height of parapet walls of corridors alongside an air-well shall not exceed 1000mm measured from its finished floor level. It shall be noted here that the ventilation openings for exit staircases in the above design layout shall not open into the air-well.
2.2.13b
Smoke-free/ fire lift lobby
A smoke-free lobby shall be separated from the adjoining areas of the building by a wall having 1-hr fire resistance.
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.
The design of a smoke-free lobby shall be such as not to impede movement of occupants through the escape route.
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, the floor area shall be not smaller than 6m² and with minimum clear width of 2m.
The floor shall be graded from the lift door towards the lobby door with a fall not exceeding 1 in 200.
A smoke-free lobby, including fire lift lobby, which acts as buffer space for entry into the exit staircase and use by firefighters during emergency, shall be maintained as common property.
A smoke-free lobby shall be ventilated through any of the following:
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, each 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.
Mechanical ventilation, except for PG II buildings, which complies with the requirements in Chapter 7.
Cross-ventilated corridor/lobby which complies with all of the following:
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.
No part of the floor area of the corridor/lobby shall be at a distance of more than 12m from the ventilation openings.
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.
Note: For residential buildings of habitable height more than 24m with single exit staircase, the requirements for the cross-ventilated corridor/lobby stipulated in Cl.9.2.1a.(4)(e) shall be complied with
Explanations & Illustrations
Clause 2.2.13b. : Smoke-free approach to exit staircase
Note : A smoke-free approach (i.e. smoke-stop lobby) is to be provided for entry into the exit staircases, even at 1st storey.
Clause 2.2.13b.(7)(a) : Smoke-free approach to exit staircase
To ensure that every part of the lobby is well ventilated, the distance between the external openings and any part of the lobby should not exceed 9m. In order that the smoke stop lobby can remain an effective buffer to the protected staircase, the former must be a common space, i.e. it should not be part of the apartment unit.
For effective natural ventilation, the smoke-stop lobby shall be within 9m of its ventilation openings. To ensure the integrity of smoke-stop lobby as dedicated buffers protecting exit staircase from smoke infiltration, it must be located in natural spaces. This arrangement would prevent any misuse by tenants, as the case may be if the lobby is to be located within a privately owned space.
For high-rise residential blocks with single exit staircase, the approach to the exit staircase is through a cross-ventilated lobby. See Cl.9.2.1a.(4)(e) & (f) for details the provision of openings to the lobby. To comply with the provision of single exit staircase, designer has to make reference to Cl.9.2.1a.(4) of the Fire Code.
Clause 2.2.13b.(7)(b) : Smoke-free approach to exit staircase
Clause 2.2.13b.(7)(c) : Smoke-free approach to exit staircase
For the purpose of measuring the horizontal distance of max. 12m from any floor space of the corridor to the ventilation openings, the ventilation openings shall be assumed to be located at the edge of the building and not at the edge of the corridor.
It is important to note that the above requirements shall not be taken to equal other clauses that call for smoke-free approach and cross ventilated lobby approach under Cl.9.2.1a.(4)(e) & (f).
The above provision of cross-ventilated corridor is not acceptable, as the ventilation opening on one side of the building is narrower than the width of the corridor. This could adversely affect the movement of air currents through the corridor, intended to draw out any smoke in the corridor area before it can affect the staircase.
Rationale
Clause 2.2.13b.(7)
Access routes to exits shall be kept smoke-free by a smoke-stop lobby, either naturally or mechanically ventilated, in order to provide a reliable means of escape for occupants and access for firefighters.
Clause 2.2.13b.(7)(a)
The minimum width of 6m and a superficial plan area of not less than 93m² of an air well have been validated through fire engineering study to provide effective smoke ventilation for a smoke-stop lobby.
2.2.13c
Exception
The omission of the smoke-free lobby required under Cl.2.2.13b. leading to the exit staircase of any building exceeding four storeys is allowed under any of the following situations, provided the door opening into the exit staircases shall have 1-hr fire resistance rating and fitted with an automatic self-closing device to comply with the requirements of Cl.3.9.2:
Where the internal exit staircase is provided with pressurisation up to a habitable height of 24m in compliance with the requirements of Chapter 7;
Where an external exit staircase is constructed to comply with Cl.2.3.3b.;
In an open-sided car park floor where cross-ventilation is provided in accordance with Cl.3.2.8a. & b., the fire door to the exit staircase can be ½-hr fire-rated.
On M&E floor of headroom not exceeding 1.5m.
The omission of a smoke-free lobby to exit staircases shall not be allowed under any of the following situations:
Where the building exceeds four storeys and belongs to PG III or VII.
Where the internal exit staircase, which is provided with pressurisation, exceeds the habitable height of 24m.
Where the exit staircase is adjacent to a fire lift as required in Chapter 6.
Explanations & Illustrations
Clause 2.2.13c.(1) : Smoke-free approach to exit staircase
Any internal exit staircase with dedicated pressurisation system (without natural ventilation) and its height not exceeding 24m will be permitted without the provision of smoke-stop lobby. The door opening into the staircase is required to have minimum 1-hr fire resistance rating.
The above smoke-stop lobby exemption is not applicable to the exit staircase adjacent to a fire lift and buildings under PG III & VII.
Smoke-stop lobby is exempted if an external exit staircase located along the perimeter wall of the building is required to be cross-ventilated having uninterrupted external openings of minimum 50% of the planal area of the staircase.
The above smoke-stop lobby exemption is not applicable to the exit staircase adjacent to a fire lift and buildings under PG III & VII.
Clause 2.2.13c.(2) : Smoke-free approach to exit staircase
The positive pressure in the pressurised staircase Figure 2.2.13c.(2) - 1 acts to force smoke away from the doorway of the staircase when that exit door is opened, thereby preventing smoke entry into the staircase. The above exemption shall apply to building of which the habitable height does not exceed 24m. This is to meet the requirements under Cl.2.3.3d.(8) and Cl.7.2.1a. which specifically require all internal staircases of building having a habitable height exceeding 24m to be pressurised. If the habitable height of the building exceeds 24m, the entry to the internal exit staircase shall be through smoke-stop lobby or external approach.
In the case of the cross-ventilated staircase (Figure 2.2.13c.(2) - 2), its open sides allow for quick dispersal of any smoke infiltrating the doorway when opened.
Hence, in both these situations, it is possible to achieve a relatively safe smoke free environment in the exit staircase for facilitating escape for its occupants. Another reason to note is that these premises warrant emergency plans and fire drills to familiarise its occupants on their procedural actions in fire emergencies.
Figure 2.2.13c.(2) - 5 : Open-sided multi-storey car park
The above requirement exempts the provision of smoke-stop lobby to exit staircases in cross-ventilated car park buildings. In Figure 2.2.13c.(2) - 4, the space before the exit staircases can satisfactorily achieve a smoke free environment. The doors to exit staircases shall be minimum ½-hr fire rated.
internal staircase serving building exceeding 24m habitable height
when adjacent to a fire lift
No exemption of the smoke-stop lobby will be granted for the exit staircase adjacent to a fire lift. The firefighters would require the lobby space as a ‘staging’ point in their fire fighting operations, prior to entering into the affected areas, in fire emergencies.
(Note: Cl 2.2.13c.(2) is not applicable to buildings under PG VII)
Smoke-stop lobby is exempted for the arrangements shown in Figures 2.2.13(c)(2) – 1 & 2 in buildings of PG II, IV, V, VI & VIII up to 60m high. The reasons for this relaxation being:
Any internal exit staircase without provision for natural ventilation and in habitable height not exceeding 60m will be provided with dedicated pressurization system. The door opening into the staircase is required to have minimum 1-hr fire resistance rating.
Partially enclosed staircase is required to be cross-ventilated having uninterrupted external openings of minimum 50% of the plan area of the staircase.
Figure 2.2.13c.(2) - 8 : Fixed unobstructed ventilation openings
Figure 2.2.13c.(2) - 9Likewise a cross-ventilated car parking storey in Figure 2.2.13c.(2) - 9 is exempted from the provision of smoke-stop lobby to exit staircase. However, the upper storeys above the car parking floors are not exempted from provision of Cl 2.2.13c.(2).
Likewise a cross-ventilated car parking storey in Figure 2.2.13c.(2) - 9 is exempted from the provision of smoke-stop lobby to exit staircase. However, the upper storeys above the car parking floors are not exempted from provision of Cl 2.2.13c.(2).
Rationale
Clause 2.2.13c.(1)(a)
The positive pressure in the pressurised staircase acts to force smoke away from the doorway of the exit staircase when the exit door is opened, thereby preventing smoke from entering the exit staircase.
Clause 2.2.13c.(1)(b)
Open sides of an external exit staircase allow for quick dispersal of any smoke infiltrated through the doorway when the door is opened. As such, a smoke-stop lobby before the external exit staircase is not necessary.
Clause 2.2.13c.(1)(c)
The doorway before the exit staircase is unlikely to be smoke logged during a fire emergency. This is because the substantial ventilation openings along the perimeter of the car park allow for quick dispersal of smoke.
Rationale
Clause 2.2.13
The smoke-free approach is intended to act as a buffer space to minimise smoke entry into the exit staircase when used by evacuees and firefighters during a fire emergency.
2.2.14
Smoke-free approach to exit staircase in basement
In a building comprising single basement storey, the entry to exit staircases need not be through smoke-free lobbies.
In a building comprising two, three or four basement storeys, entry at every basement storey level to at least one of the exit staircases serving the basement storeys shall be through a fire lift lobby even though the exit staircase is not required to be served by a fire lift. However, where the depth of the basement exceeds 9m below the average grade level and fire lifts are required in accordance with Cl.6.6.4b.(3), the entries to the exit staircases with provision of fire lifts at every basement storey level shall be through fire lift lobbies.
In a building comprising more than four basement storeys, the entry to exit staircases serving the basement storeys at every basement storey level shall be through smoke-free lobbies or designated fire lift lobbies in accordance with Cl.6.6.4b.(3).
Smoke-free and fire lift lobbies in basement occupancies shall be required to comply with the relevant provisions under Cl.2.2.13b. and shall be mechanically ventilated to comply with the requirements in Chapter 7.
Explanations & Illustrations
Clause 2.2.14a. : Smoke-free approach to exit staircase in basement
Smoke-stop lobby is required for all staircases, one of which shall be designated as a fire lift lobby. Owing to the depth of the basement, and to prevent heat and smoke from getting into the staircase, the provision of smoke-stop lobby is required. This is similar to the requirement of smoke-stop lobby to building exceeding 4 storeys above ground. Also refer to Cl.6.6.4b. for the provision of two fire lifts if basement depth exceeds 9m.
Clause 2.2.14b. : Smoke-free approach to exit staircase in basement
Smoke-stop lobby is required for at least one of the staircases. One of which shall be designated as a fire lift lobby.
At least one staircase requires smoke-stop lobby, which shall also be served as fire lift lobby. Also refer to Cl.6.6.4a. & b. which requires two fire lifts and exit staircases to be provided.
Clause 2.2.14a. : Smoke-free approach to exit staircase in basement
Smoke-stop lobby is required for all staircases, one of which shall be designated as a fire lift lobby. Owing to the depth of the basement, and to prevent heat and smoke from getting into the staircase, the provision of smoke-stop lobby is required. This is similar to the requirement of smoke-stop lobby to building exceeding 4 storeys above ground. Also refer to Cl.6.6.4b. for the provision of two fire lifts if basement depth exceeds 9m.
Rationale
Access to exits must be free of smoke and be available to building occupants at all times. Therefore, a reliable means of escape for occupants and access for firefighters shall be provided via smoke-free access route and staircases. For this reason, providing mechanical air pressuring systems to smoke-stop lobbies and exit staircases is needed to prevent smoke infiltration.
2.2.15
Area of refuge and exit reduction
When a floor area has access to area(s) of refuge in compliance with all of the following requirements in this Clause, the occupant load for which vertical exits are to be accounted for the floor area can be reduced to half when one area of refuge is provided and to one third when two or more areas of refuge are provided.
An area of refuge shall be adequate in size to hold the occupant load it receives from the floor area it serves as provision for required exit, in addition to its own occupant load calculated on the basis of 0.3m2 per person except for healthcare occupancies when the occupant load shall comply with the provisions under Cl.9.3.2b.(4).
An area of refuge shall be provided with at least one staircase for use by the occupants to gain access to other exit staircases or the ground level directly to an external space.
An area of refuge shall be entered through an external corridor and the room or space or area of refuge shall be separated from the corridor by a wall with at least 1-hr fire resistance rating.
External corridors when used as entry into an area of refuge shall conform to the requirements for 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.
Exit doors between the room or space or area of refuge and the external corridor shall have fire resistance of at least ½-hr and be fitted with an automatic self-closing device to comply with the requirements of Cl.3.9.2.
Every fire compartment in which exit reduction is permitted in connection with area of refuge shall have in addition to exit through the area(s) of refuge at least one exit staircase complying with Cl.2.3.3.
Explanations & Illustrations
An area of refuge is intended to provide only temporary point of safety to permit delayed egress travel from any level. Therefore, an area of refuge cannot be a room or space whose only access to the building spaces is through the space where the fire is located has been provided. Rather, the area of refuge must provide access to a public way via an exit such as an enclosed exit stair.
See Cl.1.4.9 and Cl.2.2.6e. for illustration.
2.3
Means of Escape Requirements
2.3.1
General
Means of escape shall be provided for all buildings by one or more of the facilities listed herein. Access and exit facilities not specifically covered in this Code shall not be used without the approval of the SCDF. Required exits shall be kept readily accessible, and doors shall be openable and unobstructed at all times during the occupancy of the building. Any future grille gate/door swing from units/service shaft into the common areas shall be indicated with dotted lines on building plans to show the egress requirements are met, despite the door swing.
Exit staircase signage
Exit staircases serving all buildings (except PG I) shall be provided with a signage not smaller than 300 x 300mm and be within the stairwell at each storey landing.
The signage shall contain the following information:
the storey number, at least 125mm in height; and
an identification of the staircase in alphabetical and/or numeric form, at least 25mm in height.
The letters and numbers on the sign can be of any colour that provides contrast with the background colour.
The signage 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.
Fire escape plan
A fire escape plan shall be provided for all buildings except PG I and displayed in common lobbies or lift lobbies such that they are easily viewable by the building occupants and the general public passing through these common areas. 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 only for firefighting and evacuation purposes and shall include the locations of the following:
Fire lifts;
Evacuation lifts;
PWD holding points;
Hose reels;
Fire extinguishers;
Manual alarm call points; and
Rising mains.
For ensuring legibility of the fire escape plan for buildings with large floor areas, partial plan showing minimally 2 escape routes is acceptable. The plan shall show the egress paths to at least 2 remotely located exits/exit staircases, including the PWD holding points.
Explanations & Illustrations
STAIRCASE IDENTIFICATION
Staircase identification is required for all buildings (except PG 1) regardless of the height of the building.
Staircase identification is to facilitate firefighting operation. It also enables the user of the staircase to orientate his location or whereabouts. This would help to alleviate any fear of disorientation by a person using the staircase during a fire emergency.
REQUIREMENT ON STAIRWAY NUMBERING SYSTEM
The numbering system is composed of square signs of at least 30cm x 30cm located, or painted, on the wall surface adjacent to the door on the stairway side.
A sign should be located at each level landing in the stairway. The bottom of the sign should be located not less than 1.5m above the floor of the staircase landing. The sign should be placed adjacent to the door and shall be visible with the door opened or closed.
The block-lettered sign may be of any colour that will contrast with the colour scheme of the stairway.
The height of the large number(s) in the middle of the sign denoting the storey should be a minimum of 12.5cm.
Section
Figure 2.3.1 - 1 : Location of sign in scissor exit staircases
Figure 2.3.1 - 2 : Example 1 25th storey of a staircase that extends from the 1st storey to the 30th storey of a 30-storey building.
The stairway terminates at the roof.
This is the ‘A’ Staircase in the building.
The number(s) and/or letter(s) at the top of the sign denoting the upper and lower terminations of the stairway should be a minimum of 2.5cm.
Identification of staircases in the building should be indicated in alphabetical and/or numeric order. The lettering height should be 2.5cm minimum, e.g., Staircase A, and located at the bottom of the sign.
Figure 2.3.1 - 3
The intent of this provision is to provide vital egress information to the occupants of a building and to firefighters. To reduce information overload to occupants during emergency egress, a sign indicating the floor level and the direction to the exit discharge is permitted to be placed as a separate sign with another sign indicating the floor level, the terminus of the top and bottom of the stair enclosure, and the identification of the stair.
Rationale
Clause 2.3.1b
The signs facilitate awareness of one's location for building occupants and firefighters within the enclosed stairway. This would help to alleviate any fear of disorientation by a person using the exit staircase during a fire emergency.
Clause 2.3.1c
The fire escape plan serves to orientate and guide the building occupants and public on the egress routes during an emergency.
These plans should be placed at common areas where the public and occupants of the building are most likely to frequent or use and can locate them easily. Such locations include common corridors, lobbies etc.
2.3.2
Exit passageways
Fire resistance
Exit passageways that serve as a means of escape or required exits from any building or storey of a building shall have the requisite fire resistance as specified under Cl.3.3.
Internal exit passageway
An internal exit passageway which serves as required exit of a building shall comply with the following requirements:
it shall be enclosed with construction complying with the provisions of Cl.3.3;
the enclosure walls shall have not more than two exit doors, excluding the final discharge door and exit staircase door, opening into the exit passageway;
exit doors opening into an exit passageway shall have fire resistance rating as required for exit doors opening into exit staircases, be fitted with automatic self-closing device and comply with the requirements of Cl.3.9.2 for fire resisting doors;
the minimum width and capacity of exit passageway shall comply with the requirements as provided in Table 2.2A;
changes in level along an exit passageway requiring less than two risers shall be via a ramp complying with the provisions under Cl.2.3.8; and
if the exit staircase which connects to the internal exit passageway is pressurised, the internal exit passageway shall also be pressurised to comply with the requirements in Chapter 7.
Explanations & Illustrations
Clause 2.3.2b. : Exit passageways
The word exit used in the term exit passageway helps to distinguish the difference between an exit passageway and an ordinary passageway or corridor. An exit passageway is an exit; it provides a path of travel offering the same level of protection and safety that is required on an enclosed exit stair. An exit passageway is a versatile feature, because it can be used to extend an exit, or, as in done in many cases, it can be used to bring an exit closer to where the occupants are located.
External exit passageway is not common in building under PG II owing to the restrictive requirements of high level ventilation of 1.8m above the finished floor level of passageway and the provision of fire doors opening into the passageway.
Exit passageway A on the first floor - the level of exit discharge – opens at one end to a five-storey exit stair enclosure and at the other end to a door to the outside. This exit passageway also serves as a horizontal continuation of, and discharge for, the stair enclosure. In serving as a discharge for the exit stair, the exit passageway must provide the same degree of protection required of the stair enclosure.
The exit passageway B, on the fourth floor, is used to provide the safety of an exit occupants travelling to the exit stair enclosure. This exit passageway might have been built to meet the travel distance limitation.
External exit passageway
An external exit passageway can be used as a required exit in lieu of an internal exit passageway. It shall comply with the following requirements:
any ventilation openings on the external wall between the exit passageway and the rest of the floor space shall be of non-combustible construction, fixed at a level of at least 1.8m, measured from the finished floor level of the passageway to the sill level of the openings and such ventilation openings shall be located not less than 3m from any opening of an exit staircase;
it is exempted from the limitations of a maximum of two exit doors opening into the exit passageway;
it can be roofed over provided the depth of the roofed over portion does not exceed 3m to avoid smoke logging;
it can be enclosed on the open side by only a parapet wall of not less than 1m and not more than 1.1m in height and the vertical height of the unobstructed and uninterrupted ventilation opening measured from the parapet wall up to the top edge of the opening or eaves of overhang shall be not less than 1.2m; and
exit doors opening into an external exit passageway shall have fire resistance rating of at least ½-hr and shall be fitted with an automatic self- closing device.
Rationale
Clause 2.3.2c
An exit passageway provides the same level of protection from the effects of fire and smoke as an exit staircase. It is an extension of an exit staircase. An exit passageway can be provided when the travel distance from the occupied space to the exit staircase exceeds the permissible travel distance.
Ventilation
All internal exit passageways shall be naturally ventilated by fixed ventilation openings in an external wall, such ventilation openings being not less than 15% of the floor area of the exit passageway.
Internal exit passageways that cannot be naturally ventilated shall be mechanically ventilated to comply with the requirements in Chapter 7.
Explanations & Illustrations
Clause 2.3.2d. : Exit passageways
Natural ventilation shall be provided to all internal exit passageway. Window openings (W) shall not be less than 15% of the floor area of internal exit passageway shown above. Where internal exit passageway cannot be naturally ventilated, mechanical ventilation shall be provided to comply with Chapter 7. The number of exit doors opening into the internal exit passageway shall not exceed two.
Note : It is uncommon to design means of escape using internal exit passageway for buildings under PG II.
Rationale
Clause 2.3.2d
An internal exit passageway is an extension of an exit staircase and shall be adequately ventilated to prevent smoke-logged during a fire emergency. Where natural ventilation is not possible, mechanical ventilation shall be provided.
2.3.3
Exit staircase
Internal exit staircase
Staircase enclosure
An internal exit staircase which serves as the required exit of the building shall be enclosed with construction complying with the provisions of Cl.3.8. The enclosure walls of an internal exit staircase, excluding the final discharge, shall not have more than two exit doors opening into the exit staircase shaft at each storey.
Explanations & Illustrations
Clause 2.3.3a.(1) :Exit staircase
This is a 5-storey building. Entry to exit staircase shall be via smoke-stop lobby.
No unprotected openings of occupancy area within 1.5m horizontally from window opening of internal staircase. See Cl.3.8 for requirements on the provision of protected shaft.
Rationale
Clause 2.3.3a.(1)
The number of door opening into an exit staircase shall be controlled so as to minimise the risk of the staircase integrity being breached. These fire doors shall be closed fully in order to act as an effective barrier against the spread of fire and smoke.
Explanations & Illustrations
Clause 2.3.3a.(2) : Exit staircase
Exit staircase is cross-ventilated & maintained under smoke-free condition at all times. Unprotected openings of the apartment or maisonette units are not facing (as shown in above figure) or ventilating into the exit staircase enclosure.
Cross ventilation provided to staircase will help to disperse smoke more readily. No unprotected openings from the shop units should face or ventilate into the exit staircase enclosure. The rear portion of shop unit C shall have 3m blank wall next to the staircase, otherwise smoke could be channelled into the staircase where there is a fire in the shop.
Explanations & Illustrations
Clause 2.3.3a.(3) - Exit staircase
Figure 2.3.3a.(3) - 1: Unprotected openings of external wall to staircase
Figure 2.3.3a.(3) - 2: Unprotected openings of external wall to staircase
Rationale
Clause 2.3.3a.(3)
The minimum separation distances between openings of an internal exit staircase and nearby unprotected openings shall be maintained. This is to reduce the risk of smoke and fire spreading into the internal exit staircase during a fire emergency.
Explanations & Illustrations
Clause 2.3.3a.(4)(b) : Exit staircase
Fire modelling using a typical model of a 3-storey car park building to evaluate whether the fire-rated doors to exit staircases within the MSCP could be permitted. The results gathered from the study indicated that occupants are able to escape safely from the staircases without being subject to untenable conditions in terms of temperature and visibility.
To qualify for the omission of the fire-rated doors in standalone car park building, the exit staircase must be positioned as remotely from one another as possible. The rationale of stipulating exit opening size is to avoid total removal of the staircase enclosures. In addition, the car park buildings must be without commercial activity or non-ancillary usage. The 3m buffer separation distance between the exit door and the nearest car park lot is intended to provide unobstructed movements to occupants getting in and out of the staircase. The omission of fire door to exit staircases is a relaxation and will eliminate maintenance aspects.
Rationale
2.3.3a.(4)(a)
The reasons for the relaxation are:
The car parking areas are provided with either automatic fire alarm or sprinkler system.
Car parking areas are usually not occupied, except during the times when people are parking or retrieving their cars.
Adequate ventilation for smoke, either by natural means or smoke purging.
Only single basement floor is involved.
Clause 2.3.3a.(4)(b)
Fire safety engineering simulations using typical model of a 3-storey car park building were carried out to evaluate whether the fire-rated doors to the exit staircases could be omitted. The result was convincing as it indicated that occupants are able to escape safely to the exit staircases without being subject to untenable conditions in terms of temperature and visibility. The rationale of stipulating exit opening size is to avoid total removal of the staircase enclosures. Other supporting reasons include cross ventilation and low occupancy.
External exit staircase
An exit staircase can qualify as an external exit staircase provided it complies with Cl.1.4.50.
An external exit staircase can be used as required exit in-lieu of internal exit staircase provided:
it complies with the requirements for exit staircase, and
there is no unprotected opening, or combustible material/construction within 3m horizontally or within 3m vertically below, or adjacent or facing it.
Exception:
In a building designed with external corridor access, the access to the external exit staircase can be by means of the open-sided external corridor adjoining the occupancy areas, subject to the following:
the external corridor shall be served by at least two exit staircases; and
unobstructed ventilation openings shall be provided along the long side of the external corridor above the parapet or balustrade; and
its final discharge leads directly to an external space.
Fire-rated doors to the external exit staircases shall be provided unless the conditions given in Cl.2.3.3a(4) are fully complied with.
Explanations & Illustrations
Clause 2.3.3b.(2)(b) : Exit Staircase
Figure 2.3.3b.(2)(b) - 1
Requirements on setback requirements under Cl.3.5 shall be used to determine the separation distance between building’s openings at A and staircase’s openings at B, subject to minimum 3m.
Heat radiation from a fire through external window in part of the building at (A) would affect occupants escaping down the external staircase at (B). To avoid this situation, the separation distance between that part of the building and the staircase shall comply with the separation requirements under Cl.3.5.
Cl.3.5 would prescribe the separation distance between that part of the building (A) and the external staircase (B) in accordance with the amount of unprotected openings provided in the external wall to part of the building (A).
Alternatively, to omit the unprotected openings in the external wall of staircase (B) facing part of the building (A).
Rationale
Clause 2.3.3b.(2)(b)
The minimum separation distances between openings of an external exit staircase and nearby unprotected openings shall be maintained. This is to reduce the risk of smoke and fire spreading into the internal exit staircase during a fire emergency.
Comparing to the internal exit staircase, a horizontal separation distance of 3m is mandated. This is because an external exit staircase has less protected enclosure.
Discharge
All exit staircases shall discharge at ground level directly into:
an external space, or
an open-sided external corridor with no commercial activity and is not more than 5m from the building eave line, or
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.
an air well of size complying with Table 1.4.2 and with discharge point at the grade level having at least 2 separated egress routes with direct access through circulation space to the building external.
Explanations & Illustrations
Clause 2.3.3c.(1) : Exit staircase
Right Figure : Axonometric view
Figure 2.3.3c.(1) - 1
Note : This relaxation follows the exemption for sprinkler provision for external open-sided linkways not exceeding 5m in width. There shall be strictly no commercial activities or storage within these areas.
Figure 2.3.3c.(1) - 2
Figure 2.3.3c.(1) - 3
Exit staircase is provided with discharge into unenclosed bridge leading to safe exterior space at ground level.
PROVISION OF ADEQUATE SEPARATION BETWEEN COMMERCIAL SPACES AND EXIT PATH
Currently, the code allows minimum 50% of the staircase exits in a sprinkler-protected building to be discharged through the ground level circulation space, which must be within 10m from exterior safe area. As there is possibility that part of the circulation space is used for commercial activities such as shops and kiosks, the SCDF conducted a study on the effect of radiation from a fire involving such commercial activities on occupants evacuating pass them. The intent of the study is therefore to look into the provision of an adequate separation between commercial activities on provision of an adequate separation between commercial spaces and the escape path such that radiation from the shop/kiosk fire would not jeopardize the occupants’ safety.
The SCDF has conducted the study through the use of CFD modelling. In the study, a sprinkler controlled 5MW shop fire was adopted. The study is confined to radiation from fire at the shop and it is assumed that the building is installed with engineered smoke control system. The study found that a minimum of 10m separation distance is needed between the commercial activities and the designated escape, as illustrated below.
Standard distance between shop and designated escape route
Rationale
Clause 2.3.3c.(2)(c)
A study on the effect of radiation from a fire involving such commercial activities on occupants evacuating pass them was initiated. In the study, a sprinkler controlled 5MW shop fire was adopted. The study concluded that a minimum of 10m separation distance is needed between the commercial activities and the designated escape route to ensure the radiation is at the acceptable level along the escape path.
Explanations & Illustrations
Clause 2.3.3c.(3) : Exit staircase
Building occupants with path of travel from the termination of an exit to a public way. This path of travel might be inside the building, or outside. Where an exit opens onto an alley, court, or yard, a safe path of travel is to be provided to a public way or some equivalent safe area. This portion of the means of egress is the exit discharge.
Forms of exit discharge are shown in Figure 2.3.3c.(3) - 1 as shaded areas.
Explanations & Illustrations
Clause 2.3.3c.(4) : Exit staircase
Figure 2.3.3c.(4) - 1
If an unprotected opening was next to the exit staircase, a separate distance of 3m was required. However, this distance can be reduced to 1.5m horizontal distance if the unprotected openings are along the same plane of the staircase exit.
Rationale
Clause 2.3.3c.(4)
The specification of minimum distance between exit staircase discharge and nearby unprotected opening serves to minimize the risk of evacuees being affected by fire and smoke emitting from openings close to the staircase discharge. These distances specified have been validated through fire engineering study.
Minimum width and capacity
The minimum width and capacity of exit staircases shall be as specified in Table 2.2A, and such staircases shall comply with all of the following:
Winders
Winders are not permitted in any building other than for access staircases in a residential unit and in such cases, there shall be not more than one winder per 90° turn.
Explanations & Illustrations
Clause 2.3.3d.(1) : Exit staircase
Winders are only permitted in access staircase within the residential unit. They shall not be provided in exit staircase. Winder is a tapered tread used to change the direction of a stairway. As it introduces a sudden change in the stair geometry, winder could cause unwary occupants to trip and thus winder is not permitted in non-residential building.
Rationale
Clause 2.3.3d.(1)
A winder is a tapered tread used to change the direction of a stairway. As it introduces a sudden change in the stair geometry, a winder could cause unwary occupants to trip and fall.
Explanations & Illustrations
Clause 2.3.3d.(2) : Exit staircase
Circular staircases are not recommended for use as exit staircases due to their varying tread size, which can cause escaping occupants to lose footing and falling more frequently than straight run staircases. However, it may be permitted with limitations as provided for under Cl.2.3.7, or otherwise consented by the SCDF.
Rationale
Clause 2.3.3d.(3) to (5)
In view that BCA does not have any specific requirements for staircase landings, risers, treads and headroom for specific usages or spaces and has removed them from its code. These requirements are reinstated in this edition of the Fire Code to ensure the exit staircases meet minimum requirements for safe evacuation of occupants and access by firefighters for rescue and firefighting.
Explanations & Illustrations
Clause 2.3.3d.(6) : Exit staircase
Handrail provides support for people using the stair. It also serves as a guide when smoke enters the stairway in a quantity sufficient to interfere with ones vision or when the stair lighting system fails. Handrail may be constructed of timber or metal with plastic finish.
Rationale
Clause 2.3.3d.(6)
Handrail provides support for occupants using the staircase. It also serves as a guide when smoke enters the staircase in a quantity sufficient to interfere with one’s vision, or when the exit staircase emergency lighting system fails. Staircase of not more than 1.25m in width is not too wide and evacuees using it can easily reach the handrail for support/guidance if necessary.
Explanations & Illustrations
Clause 2.3.3d.(7) : Exit staircase
Figure 2.3.3d.(7)
Exit staircase and occupancy area shall not share the same air well or void for lighting and ventilation to prevent smoke from being drawn into the staircase, unless otherwise permitted by the SCDF.
Rationale
Clause 2.3.3d.(7)
The minimum ventilation openings stipulated provide effective smoke ventilation for exit staircases. These dimensions have been validated through fire engineering study.
Explanations & Illustrations
Clause 2.3.3d.(8) : Exit staircase
In addition to the provision of pressurisation, the entry into the internal staircase shall be through a smoke-stop lobby. The smoke-stop lobby acts as a buffer to prevent smoke from getting into the staircase. It is not common to have pressurised staircase for buildings under PG II.
Where the internal exit staircase is pressurised, there shall be a means to activate the pressurisation fan system.
Explanations & Illustrations
Clause 2.3.3d.(9) : Exit staircase
Figure 2.3.3d.(9) - 1
This is a relaxation towards the mode of ventilation whereby the lower part of exit staircase is mechanically ventilated instead of pressurised. This provision is only possible if the habitable height of the lower part of staircase shaft is less than 24m. No door is required within the staircase shaft to separate different mode of ventilation provision.
Figure 2.3.3d.(9) - 2
Lower part of staircase shaft where habitable height exceeding 24m, it shall be pressurised. Door at the mid-landing separating the naturally ventilated and pressurised portion of exit staircase shall be provided to enable effective pressurisation.
Rationale
Clause 2.3.3d.(9)
This clause serves to address different modes of ventilation allowed within a single staircase shaft. Door at landing is only permitted for a partially pressurised internal exit staircase for the purpose of maintaining positive pressure within the staircase.
2.3.4
Scissor exit staircase
Scissor exit staircase shall comply with the following:
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 having fire resistance for a minimum period equal to that required for the enclosure;
such scissor exit staircases shall comply with all applicable provisions for exit staircase;
for exit door openings of scissor exit staircases, the separation distance between the two closer edges of staircase doors shall be at least 7m;
where there is only one pair of scissor exit staircases, the door opening into scissor exit staircases shall be spaced at least 1/3 the diagonal dimension of the area to be served in a sprinkler-protected building and ½ the diagonal dimension in a non-sprinkler-protected building in accordance with Cl.2.3.12; and
Explanations & Illustrations
Clause 2.3.4a.-d. : Scissor exit staircase
the ventilation openings of each staircase shall be located on alternate storeys if such openings or windows are serving both staircases on the same wall.
Explanations & Illustrations
Clause 2.3.4e. : Scissor exit staircase
Figure 2.3.4e. - 1 : Ventilation openings
Ventilation opening sizes are to comply with Cl.2.3.3d(7).
Where there is only one pair of scissor exit staircases, designer shall ensure Cl.2.3.4d. is strictly adhered to. If the minimum 7m is less than the computed diagonal distance, the designer shall apply the latter diagonal separation distance.
Figure 2.3.4e. - 2 : Scissor stair
Rationale
Clause 2.3.4e
The purpose of this arrangement of ventilation openings for a scissor exit staircase is to ensure that if one of the staircase if breached, the smoke flowing out from that staircase ventilation opening will not enter into the other staircase.
2.3.5
Basement exit staircase
Any exit staircase which serves a basement storey of a building, unless otherwise stated in Cl.2.3.3a.(4)(a), shall comply with all the applicable provisions for exit staircase.
Such exit staircase shall not be made continuous with any other exit staircase which serves a non-basement storey of the building.
Explanations & Illustrations
Clause 2.3.5b. : Basement exit staircase
Separate protected shaft
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.
Explanations & Illustrations
Clause 2.3.5c. : Basement exit staircase
Figure 2.3.5c
The provision of compartment wall is to separate the basement staircase from the non-basement staircase so that each is located in a separate shaft.
Upper storey staircase that continues into basement
Where upper storey staircase is allowed by the SCDF to be continuous with that serving a basement which is naturally ventilated, all of the following shall be complied with:
Entry at basement
The entry into the basement staircase shall be through a protected lobby, or directly from the basement occupancy area provided the door to the basement staircase is at least 1-hr fire-rated.
Barrier
To prevent occupants exiting continuously from upper storeys into the basement storey during an emergency, a physical barrier in the form of a door or gate (self-closing type) shall be provided across the staircase landing at ground level to separate the discharge route of upper storeys from the basement staircase.
Smoke-free lobby
A smoke-free lobby shall be provided for entry into the staircase at all storeys, including basement storeys if the staircase serves more than four storeys, including basement storeys.
Signage
Appropriate signage shall be provided inside the staircase enclosure to direct occupants out of the building at ground level.
Explanations & Illustrations
Clause 2.3.5d.(2) : Basement exit staircase
This can be done by placing a physical barrier, like the gate shown above, to prevent occupants from continuing to the basement in emergency. This, together with the aid of exit directional sign, helps to alert occupants in the stair enclosure that they are on the level of exit discharge.
Rationale
Clause 2.3.5d.(2)
The barrier serves as a physical restriction to prevent occupants evacuating from upper storeys from continuing into the basement levels. This, with the aid of an exit directional sign, would help to alert occupants in the staircase enclosure that they on the level of exit discharge.
2.3.6
Hardwood staircase
A hardwood staircase can be used as an internal access staircase in building.
Where timber staircases are used in units in PG I and II buildings, which are not under conservation, the structural elements such as the stringer supporting the treads and risers shall be constructed of non-combustible materials.
Explanations & Illustrations
Clause 2.3.6 : Hardwood staircase
Figure 2.3.6 : Unenclosed staircase
As stringer is considered as part of an element of structure, it shall be of non-combustible material having the necessary fire resistance rating of ½ hour or 1 hour as the case may be under Cl.3.3
Hardwood staircase is allowed to be used as internal access staircase.
2.3.7
Spiral staircase
Spiral staircases shall not serve as required exits, unless they comply with all of the following conditions. They shall:
be external and unenclosed;
serve only mezzanine floors, balconies, or any storey of occupant load not exceeding 25 persons;
be constructed of non-combustible materials;
have a tread length of at least 750mm; and
be not more than 10m high.
Spiral staircase shall not be designed as the sole means of escape for buildings under PG I and for PG II maisonettes and penthouses.
Explanations & Illustrations
Clause 2.3.7 : Spiral staircase
Minimum and maximum dimensions for spiral stairs are shown above. All treads must be identical, and the stair can serve a maximum occupant load of 25 persons. Spiral staircase is slightly different from curved or other geometric staircases, as all its treads must be identical, subject to a height restriction of 10m and being located on the external facade of the building to qualify as exit staircase.
As spiral staircase is very steep and winding, the time taken by occupants to exit downwards during an emergency would be much longer, hence there is a need to limit the occupant load to max. 25 persons. In permitting the spiral staircase to be used as exit staircase in case of fire, and for rescue and firefighting operations by firefighters, the width of the staircase should not be less than 750mm. This width would be just adequate to permit movement of firefighters in full body gear and carrying casualties in moving down the stair.
Rationale
Clause 2.3.7
Spiral 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 footings.
2.3.8
Exit ramp
Internal and external exit ramps can be used as exits in lieu of internal and external exit staircases subject to compliance with Cl.2.3.3 and all of the following:
Slope
The slope of such exit ramps shall not be steeper than 1 in 10.
Changes in direction
Exit ramps shall be straight with changes in direction being made at level platforms or landings only, except that exit ramps having a slope not greater than 1 in 12 at any place can be curved.
Explanations & Illustrations
Clause 2.3.8b. : Exit ramp
Circular ramp having a gradient not greater than 1:12 is acceptable as an exit ramp.
Platform
Level platforms or landings shall be provided at the bottom, at intermediate levels where required and at the top of all exit ramps.
Level platforms shall be provided at each door opening into or from an exit ramp.
The minimum width and length of a platform or landing 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.
Explanations & Illustrations
Clause 2.3.8c. :Exit ramp
Guards and handrails
Exit ramps shall have walls, guards or handrails and shall comply with the applicable requirements of Cl.2.3.3d. for exit staircases.
Surface
All exit ramps shall be provided with non-slip surface finishes.
Ventilation
Exit ramps shall be ventilated to comply with the requirements for ventilation of exit staircases.
Enclosure exemption
Exit ramps serving a single storey basement of PG II to VII buildings are not required to be protected with fire-rated enclosures, provided the travel distances measured to the exit doors at ground level comply with Table 2.2A.
Explanations & Illustrations
Clause 2.3.8d. & g. :Exit ramp
Figure 2.3.8d. & g.
Occupants using the exit ramp would be able to travel at a quicker pace to exit directly into the exterior space at grade level. As only one level is involved and that final exit is within sight of exiting occupants, there is no need to protect the ramp with enclosure walls, provided travel distance is measured to the door at grade level and complies with Table 2.2A.
All exit ramps shall be constructed of non-combustible materials to have the necessary fire resistance rating as exit staircase. Similarly, the width of the exit ramp shall have the adequate exit capacity to receive the occupant load from the floor space it serves.
Rationale
Clause 2.3.8
A ramp can be used for vertical exit similar to that of an exit staircase provided its gradients meet the requirements. This is to prevent accidents as steep or abrupt elevations may cause tripping or hamper movement during evacuation.
2.3.9
Exit doors and exit access doors
Exit doors and exit access doors shall comply with all of the following:
Door operation
Exit/ exit access doors shall be capable of being opened manually, without the use of a key, tool, or special knowledge or effort for operation from the inside of the building. (Not applicable within residential units under PG I and II)
Rationale
Clause 2.3.9a.
Occupants of PG I & II buildings are familiar with the floor layouts and exit facilities of their own premises. Hence, there isn’t any need to control how the exit doors of the units should be secured in order not to hamper escape during an emergency.
Fire resistance
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
Door swing
Exit doors and exit access doors shall open in the direction of exit travel in the following situations:
when leading to an area of refuge, exit and exit passageway, or
when used in an exit enclosure, including smoke-free and fire lift lobbies in a building, but excluding doors of individual residential units that open directly into an exit enclosure, or
when serving a high hazard area, or
when serving a room or space with more than 50 persons.
Exit/ exit access door openings
Opening into exit staircase
Exit doors opening into exit staircases and exit passageways shall not impede the egress of occupants when such doors are swung open.
Explanations & Illustrations
Clause 2.3.9d.(1) : Exit doors & exit access doors
Doors serving as main entrance into an enclosed stair shall not unduly block the stair landing or the stairs. The door shall not reduce the required width either during its swing or while at rest, i.e. B shall be > A and C shall be < 80mm.
Explanations & Illustrations
Clause 2.3.9d.(2) : Exit doors & exit access door
Doors in horizontal exits shall not be required to swing in the direction of egress travel if the occupant load within the unit space is less than 50 persons.
Doors A & B are positioned directly each other. It is to be noted that doors shall not be arranged to swing in a direction that blocks the use of the corridor when both are open.
Vision panel
The fire door to an exit 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. The provision of vision panel shall not apply to fire doors of residential apartment or maisonette units.
Explanations & Illustrations
Clause 2.3.9e. : Exit doors and exit access doors
Fire doors with vision panels 60,000 m² shall pass the fire test under BS 476: Part 20 – 23.
Fire rated glass doors shall only be permitted in sprinkler-protected buildings. In addition, any oversized (>60,000mm²) glass panels in the doors and fire-rated glass doors shall meet the Class A of the Impact Performance requirements when subject to test under BS 6206 or AS 2208. To overcome direct heat radiation through the doors, the oversized glass doors or fire-rated glass doors would be required to pass the fire test on insulation requirements under BS 476: Part 20 – 23, subject to complying with Cl.3.15.13, which prohibits fire rated glass door to protected shafts containing exit staircase and fire lift. The lowering of vision panel to height not higher than 900mm and top edge lower than 1500mm is in line with the Accessibility Code requirement and enable firefighter to appreciate the situation during a fire emergency.
There is no need to provide vision panel to the entrance door of residential units.
rationale
Clause 2.3.9e
The main purpose of vision panel is to enable firefighters to appreciate the fire situation within the occupied spaces before entering. It will also help to prevent wheelchair users from being accidentally struck/knocked by the door swing. The revised vision panel mounting height of 1200mm to 900mm was also found to be suitable for use by wheelchair users.
Revolving doors
Revolving doors shall not be used as exit/ exit access doors for required exits.
Explanations & Illustrations
Clause 2.3.9f. : Exit doors & exit access doors
Revolving doors are not acceptable as exit door as the revolving mechanism would mal-function and the speed of egress is slow.
Due to the risk of jamming, conventional type of revolving doors are not normally allowed as doors for means of escape purposes. Where such door is used, exit door must be clearly indicated with exit sign.
Rationale
Clause 2.3.9f
Owing to the high possibility of jamming, revolving doors cannot be accepted as exit doors for escape purposes. When a revolving door is present, an exit door with an exit sign shall be provided adjacent to it.
Exit/ exit access door of residential unit
Exit/ exit access door of each residential unit shall be located at not more than 500mm from the strata-title line to prevent the creation of a large entrance alcove/ corridor. However, in situations where the entrance alcove/ corridor leads into an open- sided common corridor which meets the requirements for smoke-free approach under Cl.9.2.1a.(4)(e) & (f), the separation distance between the entrance alcove/corridor and the nearest exit staircase shall not be less than 3m.
Explanations & Illustrations
Clause 2.3.9g. : Exit doors & exit access doors
Separation distance between grilles/gate and exit staircase shall not be less than 3m.
Rationale
Clause 2.3.9g
The purpose of controlling the depth and location of the entrance alcove/corridor is to limit/prevent storage of combustible items within this space and to maintain the integrity of the egress path and the exit staircase(s).
Door located in a path of travel
Any door located in a path of travel shall be of the side-hinged or pivoted swing type. The door shall be designed and installed so that when swung open, it does not prevent full use of the opening. The minimum clear width of the door opening shall not be less than the required door clear width.
Exception
Requirement on door swing shall not apply to buildings under PG I and residential units under PG II.
Locking device
With prior consent from the SCDF, locking of exit/ exit access doors are permissible at certain rooms or spaces of healthcare occupancies and detention and correctional occupancies.
Sliding doors & roller shutters
Sliding door and roller shutter as listed in Cl.2.3.9h.(2)(a) to (e) below are permitted to be installed across the exit access leading to exits, including the exterior door openings, except in areas stipulated under Cl.2.3.9c.(1) and (3). These doors shall not form part of the fire compartment integrity.
Explanations & Illustrations
Clause 2.3.9h.(2)(b) : Exit doors & exit access doors
If the occupant load to a room or space exceeds 50 persons, sliding door or roller shutter located across means of escape shall be kept in the open position during the period when the premise is occupied. The main concern is that extra effort and time would be needed to manually open the roller shutter or sliding door. Alternatively, wicket door can be built into the roller shutter or sliding door.
For warehouse buildings, most of the time the warehouse area would not be occupied unless there is a need to move goods or materials in or out of the building. Also, the actual number of people occupying a warehouse is usually very low.
For the above reasons, when the warehouse area is occupied, selected roller shutters or sliding doors that are not provided with wicket doors and located across means of escape would be kept in the open position to provide the required means of escape in an emergency.
However, should any warehouse building be open to the public for the purpose of Warehouse Sale, all the roller shutters or sliding doors, that are not fitted with wicket doors and located across the means of escape in the warehouse area, are required to be kept in the open position when the premise is occupied.
In areas provided with A/C or MV and the roller shutters or sliding doors are required to be kept in the closed position most of the times, wicket doors shall be incorporated into the roller shutters or sliding doors. Alternatively, a by-pass exit door shall be provided next to the roller shutter or sliding door that is to be kept in the closed position most of the times.
All roller shutters or sliding doors that are not provided with wicket doors and located across means of escape are required to be kept in the open position when premise is occupied.
Clause 2.3.9h.(2)(c) : Exit doors & exit access doors
Figure 2.3.9h.(2)(c) - Wicket door
Wicket doors are permitted to be incorporated within a roller shutter or sliding door. The wicket doors shall be able to perform the same functions as side hinged door and shall be able to be swung open in the direction of exit travel when used. Wicket doors shall comply with all requirements of exit access door, clearly marked and readily visible.
Clause 2.3.9h.(2)(e) : Exit doors & exit access doors
Members of the public and building owners opined that powered sliding doors, roller shutters and swing doors that belong to unit owners or tenants should not be linked to the building fire alarm system. The main concern is that in the event of false alarm, such doors would be activated to open, thus posing security risk to the unit owners and tenants.
In response to the feedback, it was decided that powered sliding doors, roller shutters and swing doors that belong to the unit owners or tenants are not required to be linked to the building fire alarm system, provided that they are designed fail safe type, installed with manual over-ride, and do not form part of the building’s protection system, for example, smoke control systems.
Rationale
Rationale - Clause 2.3.9h.(2)(e)(ii)
The provision of manual override mechanism is an additional measure to ensure occupants can still get out of their unit should the powered-operated door/shutter failed to open its door/shutter on activation of the building fire alarm and/or localised detector.
Exit/ exit access door serving spaces of mass occupation
Any exit door or exit access door serving spaces of assembly/ mass occupation, namely, auditorium, concert hall, theatre, assembly hall, exhibition hall, conference hall, cinema, stadium, function hall, casino, or any other spaces with an occupant load factor of not greater than 1m2/person and occupant load greater than 50, which has to be kept shut and fastened while the building or part of the building is occupied shall be fitted with ‘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.
Locking of doors to exit staircase, smoke-free lobby and fire lift lobby
One-way locking device e.g. panic bolt or thumb turn locking device is not permitted under the following situations:
for the exit door between exit staircase and fire lift lobby;
for the exit door between exit staircase and smoke-free lobby/ fire lift lobby/ occupancy area on re-entry floor; and
for the exit access door between smoke-free lobby/ fire lift lobby and occupancy area on re-entry floor.
Rationale
Clause 2.3.9i
The purpose of panic exit device is to provide an intuitive means of escape for spaces housing large crowds to prevent stampede in a panic situation.
Clause 2.3.9j
The specific doors shall not have locking device so as to enable firefighting crews to have direct and immediate access to occupied spaces. This requirement will cut down unnecessary time wasted on breaking open the locked doors.
Access control using electromagnetic/electromechanical locking device
Where access control using electromagnetic/ electromechanical locking device is installed on any exit access door and/or exit door, excluding revolving doors and doors to residential units, such doors shall comply with the requirements stipulated in Table 2.3.9k.(1) - 1 & Table 2.3.9k.(1) - 2. The access control locking devices installed on exit access door and/ or exit door in the escape path shall be connected directly to the building automatic fire alarm system to de-activate the locking devices. Linking of the locking devices or its control panels through other systems such as access control, building management system, etc., that will cause delay to the de-energising of locking devices is not permitted.
Access control belonging to tenanted spaces
Where the escape route is permitted to go through another occupied space in accordance with Cl.2.2.12b., the exit access door within the tenant unit for escape purpose shall release when the alarm on that floor activates.
Where doors opening into a passenger lift lobby are provided with access control and are locked after normal operation hours, the lobby shall be designed to have direct access to at least one exit staircase to prevent any occupant from being trapped in the lobby when the lifts are recalled to the 1st storey, or other designated floor during fire emergency or building power failure.
Staircase re-entry
Every exit staircase enclosure serving more than 7 storeys of a non- residential building, excluding buildings of detention and correctional occupancies, shall allow re-entry from the staircase enclosure to the interior of the building. There shall be at least one level where it is possible to re-enter into the interior of the building from the exit staircase enclosure.
The re-entry points shall be located not more than 6 storeys apart. There shall not be more than three storeys above the highest re-entry door in the building.
Where re-entry is provided from the staircase enclosure, it shall open into a common corridor that is connected directly to at least one other exit staircase.
Exit doors permitting re-entry into the building, shall be identified with a signage “Re-entry door” of at least 50mm lettering height on the staircase side of the exit door.
Where locking is required for doors of smoke-free lobby, fire lift lobby or exit staircase on the re-entry floor, they shall be fitted with an electromagnetic/ electromechanical locking device complying with Cl.2.3.9k.(1). For re-entry floor, manual override device shall be provided on both sides of the door.
All non-re-entry floors shall be identified with a sign to show the designated re-entry floors on the staircase side of the exit door.
Warning signage for exit doors with one-way lock
Where one-way locking devices or electromagnetic/ electromechanical locking devices are installed at the doors of exit staircases, a signage shall be provided to warn occupants that they would not be able to re-enter the floor should they exit from it. A readily visible sign with the lettering “EXIT ONLY, NO RE-ENTRY TO BUILDING” shall be positioned at the entrance into the exit staircase. This signage shall be applicable for all buildings except PG I & II.
Access control using digital locksets
Where a digital lockset is installed on an exit door or exit access door, these digital locksets shall come with mechanical fail-safe features on the non-secure side (i.e., shall not rely on electrical energy) to ensure occupant escape.
Explanations & Illustrations
Clause 2.3.9l. : Exit doors & exit access doors
Figure 2.3.9l. - 1 : Example of a 9-storey building requiring 1 re-entry point to the exit staircase
Occupant A needs not travel more than 3 floors up to gain re-entry at 8th storey .The main purpose of re-entry door is to allow occupants to re-enter the building space to look for an alternative exit via a common corridor. This need would arise if the evacuation descend in the staircase is being held-up because of locked exit door at 1st storey or other reasons.
Figure 2.3.9l. - 2 : Example of a 10-storey building requiring 1 re-entry point to the exit staircase
Occupant B needs to travel 2 floors down to gain re-entry at 8th storey.
Figure 2.3.9l - 3 : Example of a 11-storey building requiring 1 re-entry point to the exit staircase
Occupant B needs to travel not more than 3 floors down to gain re-entry at 8th storey.
Figure 2.3.9l. - 4 : Example of a 12-storey building requiring more than 1 re-entry point to the exit staircase
Occupant B needs to travel more than 3 floors down to gain re-entry at 8th storey. An additional re-entry point to each exit staircase shall be provided.
Figure 2.3.9l. - 5
For staircase enclosures serving more than seven storeys, more than two unlocked re-entry points are required. This arrangement provides flexibility, especially in office buildings that, for security reasons, might need to prevent re-entry on certain floors. At the same time, the provision ensures that one can re-enter the building without having to travel up or down too many flights of stairs. Any door providing a way out of the staircase enclosure must be identified as such on the stairwell side.
Typical office floor plan – Staircase doors that provide re-entry to the floor space shall be linked to at least one other exit staircase via common corridor.
Rationale
Clause 2.3.9l
The concept of re-entry floor is originated from the recommendation by the National Institute of Standards and Technology (NIST) after the 911 incident. The purpose is to facilitate occupants ability to gain access to another exit staircase should the egress via an exit staircase be blocked off or it being rendered unusable in an emergency situation.
2.3.10
External corridor
External corridor shall comply with the following requirements:
the vertical height of the unobstructed and uninterrupted ventilation opening measured from the parapet wall/ balustrade/ grille/ railing up to the top edge of the opening or eaves of overhang shall not be less than 1.2m;
where the external corridor is roofed over, the depth of the covered area/ portion shall not exceed 3m;
where any room or space with sleeping risk is located along the corridor, a 1-hr fire resistance rating wall of height not less than 1.1m, measured from the finished floor level of the external corridor to the sill level of the opening, shall be provided along the corridor leading to the exits. Any ventilation openings above the fire-rated wall shall be of non-combustible construction;
the door opening into the external corridor need not be fire-rated;
the provision of parapet wall, or balustrade for an external corridor shall be at least 1m in height and at most 1.5m in height along the outer side of the corridor; and
the length of unobstructed and uninterrupted openings above the parapet wall of the external wall shall not be less than 6m and shall abut an external space.
Explanations & Illustrations
Clause 2.3.10a. : External corridor
Safety barrier of dimension not greater than 50 X 50mm or diameter 50mm is permitted to be installed above the parapet wall/balustrade. Where this dimension is exceeded, the required clearance of 1.2m above the parapet wall/balustrade shall be measured from the top of the safety barrier to the underside of the eaves of overhang. There is no control on the installation height "H" of the safety barrier.
Clause 2.3.10d. : External corridor
As external corridors, mentioned in Cl.2.2.13 and Cl.9.2.1a.(7), would be able to provide good venting for smoke and heat, doors of apartment or maisonette units opening into such external corridors, as shown in Figure 2.3.10d., need not have fire resistance rating.
2.3.11
Air well
The minimum size of an air well shall comply with Table 1.4.2 for ventilation of:
exit staircases; and
exit passageways (as an extension to an exit staircase).
An air well shall have a minimum clear area of 93m2 and minimum width of 6m and without obstruction vertically throughout the airspace for ventilation of:
smoke-free lobby;
external corridor;
external exit passageway;
cross-ventilated corridor/lobby;
common internal corridor stipulated under Cl.9.2.1a.(10)(b); and
internal corridor of hotel, hostel, service apartment, healthcare occupancy, workers’ dormitories and the like.
2.3.12
Remoteness of exits
Where more than one exit is required from a building or portion thereof, 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 rendered unusable by any one fire or other emergency condition.
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 building or area to be served, measured in a straight line between the furthest edges of the exit doors or exit access doors (see Diagram 2.3.12b. - 1 to 5), subject to the following:
if the distance between the 2 exits or exit access doors is less than half the length of the maximum overall diagonal dimension of the building or area to be served, it shall be considered as a one-way escape arrangement;
the separation distance measured in a straight line between the furthest edges of the doors of the two exits (exit staircases, exit passageways or exit ramps) shall not be less than 7m.; and
for PG II buildings, the separation distance of the exits on the residential floor shall not be less than half the length of the maximum overall diagonal dimension of the protected lobby/corridor or external corridor.
Explanations & Illustrations
Clause 2.3.12b. : Remoteness of exits
Right : Figure 2.3.12b. - 2
Right : Figure 2.3.12b. - 4
Left : Figure 2.3.12b. - 3
One-way escape arrangement
The distance between the exit of staircases S1 & S2 is less than half the length of the max. overall diagonal dimension of the building or floor space.
Right : Figure 2.3.12b. - 4
Two-way escape arrangement
Exit separation between the exit staircases S1 & S2 can be based on the travel distance in the exit access corridor enclosed with 1-hr fire-rated walls and ½-hr fire-rated door.
Reduction in exit separation
In buildings 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.2.3.12a.& b. shall be not less than one third the length of the maximum overall diagonal dimension of the building or area to be served. The separation distance measured in a straight line between the furthest edges of the doors of the two exits (exit staircases, exit passageways or exit ramps) shall not be less than 7m.
Explanations & Illustrations
Clause 2.3.12c. : Remoteness of exits
The minimum separation distance (E1) and door (E2) shall not be less than ⅓ the maximum overall diagonal dimension of the building (D).
Exit separation measured along exit access corridor
Where two exit staircases, exit passageways or exit ramps are inter-connected by a corridor, exit separation can be measured along the line of travel within the exit access corridor. The exit access corridor connecting the exit staircases, exit passageways or exit ramps shall be protected by minimum 1-hr fire-rated enclosures. Doors opening into this corridor shall have minimum ½-hr fire resistance rating (see Diagram 2.3.12d.). The separation distance measured along the line of travel within the exit access corridor between the furthest edges of the doors of the two exits (exit staircases, exit passageways or exit ramps) shall not be less than 7m.
Explanations & Illustrations
Clause 2.3.12d. : Remoteness of exits
Remoteness of exits is measured along 1-hr fire-rated corridor with ½-hr fire doors. In place of measuring physical distance between exit stair enclosures, distance for purposes of determining remoteness is permitted to be measured along a protected corridor, provided the separation distance between the furthest edges of the doors of the two exits is not less than 7m.
When there is only one pair of scissor exit staircase, the door opening into scissor exit staircases shall be spaced at least ⅓ the diagonal dimension of the area to be served in a sprinkler-protected building and ½ the diagonal dimension in a non-sprinkler-protected building in accordance with Cl.2.3.12.
Door opening into scissor exit staircase shall be at least 7m measured as travel distance between the two closer edges of the staircase doors. The line of measurement for scissor exit staircase is measured to the nearest edge instead of furthest edge of the exit doors.
One-way travel
A one-way travel or “common path” exists if a floor space is arranged or provided with partitioning works such that occupants within that space are able to travel in only one direction to reach any of the exits or to reach the splitting point where they have the choice of two or more routes of travel to remote exits.
The travel distance from the most remote point to the splitting point shall not exceed the permissible one-way travel distance allowed in Table 2.2A. At the splitting point, the angle of divergence between any two alternative routes shall not be less than 90º in order that the routes originating from the splitting point can be considered as two-way travel.
The aggregate travel distances of the one-way travel from the most remote point to the splitting point and the continuous two-way travel from the splitting point to the nearest exit shall not exceed the permissible two-way travel distance allowed in Table 2.2A.
Explanations & Illustrations
Clause 2.3.12e. : Remoteness of exits
Remoteness of exits is measured along 1-hr fire-rated corridor with ½-hr fire doors. In place of measuring physical distance between exit stair enclosure, distance for purposes of determining remoteness is permitted to be measured along a protected corridor.
2.4
Special Requirements for Persons with Disabilities (PWDs)
2.4.1
General
The following buildings/ usages/ areas are exempted from these requirements:
PG I and II buildings;
hospitals and nursing care facilities;
buildings/ usages/ areas that are exempted from barrier-free accessibility compliance, as required by the authority having jurisdiction on accessibility in the built environment; and
non-residential buildings/ usages/ areas, such as car parks, clubhouses and gardens/ terraces located within residential developments and which are intended for ancillary use, are not required to comply with these requirements; and
PG III to VIII buildings that are not served by any lift.
The escape routes shall be free from any obstacle that may cause undue delay to PWDs during evacuation, e.g. raised thresholds or steps. Where there are minor changes in level within any storey, a ramp conforming to the requirements stipulated in the “Code on Accessibility in the Built Environment” shall be provided.
2.4.2
PWD Holding Point
Purpose
A PWD Holding Point shall be provided on all storeys, including all basement levels, except first storey or storey at grade level, for PWDs to safely wait for assistance in evacuation.
Siting of PWD Holding Point
There shall be at least two designated PWD Holding Points remotely positioned on every storey of a building except for a building designed with a single exit staircase allowed under this Code. The corridor serving as escape route shall have a minimum clear width of 1.2m.
The PWD Holding Point shall be kept free of obstruction and sited within the following locations/ areas in the order of priority (see Diagrams 2.4.2b.(2) – 1 to 4):
Evacuation lift lobby.
Fire lift lobby.
Smoke-free lobby or external corridor.
Exit staircase.
The PWD Holding Point located in the above areas shall be positioned away from the edge of the exit staircase and path of person escaping from the occupied space. It shall not reduce/ encroach onto the required dimensions/ spaces of the above areas.
Signage
Where a PWD Holding Point is located, a mandatory sign worded “PWD Holding Point” shall be prominently displayed.
2.4.3
Communication provisions
A suitable means of communication, as required under Cl.6.6.5c.(4), shall be provided between the PWD holding point and FCC or any 24-hourly manned station, for PWDs to call for assistance during a fire emergency. It can be in the form of a distress button or dedicated voice communication. The dedicated voice communication handset shall always be accessible and not to be locked. The means of communication shall:
be located between 800mm and 1.2m above finished floor level;
be appropriately labelled;
be provided with prominently displayed clear instruction sign on its operation; and
generate a clear visual indication to indicate that the distress signal has been relayed.
2.4.4
Dimension requirements of PWD Holding Point
A PWD Holding Point shall be adequately sized so as to accommodate a wheelchair user and to allow the user to manoeuvre easily. In this respect, the PWD Holding Point shall meet the following requirements:
the space provided for a wheelchair in a PWD Holding Point shall be at least 900mm X 1.4m to allow for manoeuvring of the wheelchair;
where a PWD Holding Point is sited inside an exit staircase, smoke-free lobby or fire lift lobby, the wheelchair space shall not result in reduced size of these spaces and its access shall not obstruct the flow of evacuation; and
the PWD Holding Point shall be marked on the ground with a wheelchair symbol in white against contrasting background, with a dotted white rectangular outline.
2.4.5
Protection of PWD Holding Point
A PWD Holding Point shall be enclosed with fire-resisting construction (other than any part that is an external wall of a building) and shall be served directly by a safe route to a storey exit, evacuation lift or final exit.
2.4.6
Exit staircase
Handrails
The handrails within an exit staircase shall be continuous.
Wheelchair stairlifts
A wheelchair stairlift, where installed, shall be sited inside an exit staircase. Such a stairlift, when in operating position, shall not encroach into the escape path of building occupants.
2.4.7
Ramp
Related Diagrams & Tables
One-way escape arrangement
The distance between the exit of staircases S1 & S2 is less than half the length of the max. overall diagonal dimension of the building or floor space.
Two-way escape arrangement
Exit separation between the exit staircases S1 & S2 can be based on the travel distance in the exit access corridor enclosed with 1-hr fire-rated walls and ½-hr fire-rated doors.
Remoteness of exits is measured along 1-hr fire-rated corridor with ½-hr fire doors. In place of measuring physical distance between exit stair enclosure, distance for purposes of determining remoteness is permitted to be measured along a protected corridor.
TABLE 2.2A : DETERMINATION OF EXIT REQUIREMENT | ||||||||||||
Type of Occupancy | Max Travel Distance(m) | Capacity No of persons per unit of width(x) | Min Width (m) | Max Dead End (m) | ||||||||
One-way travel | Two-way travel | |||||||||||
Non-sprinklered | Sprinklered | Non-sprinklered | Sprinklered | Door opening(c), (d) & (e) | Staircases(f) | Ramps Corridors Exits Passageways(d) | Staircases/ Exit Passageway | Corridors(l) | Corridors | |||
Exit to outdoors at ground level | Other exit & corridor doors | Non-sprinklered | Sprinklered | |||||||||
High hazard | 10 | 20 | 20 | 35 | 50 | 40 | 30 | 50 | 1 | 1.2 | 15 | 20 |
Industrial buildings (factories, workshops, godown/ warehouse) | 15 | 25 | 30 | 60 | 100 | 80 | 60 | 100 | 1 | 1.2 | 15 | 20 |
Shops, healthcare facility (outpatient) | 15 | 25 | 45 | 60 | 100 | 80 | 60 | 100 | 1 | 1.2 | 15 | 20 |
Offices | 15 | 30 | 45 | 75 | 100 | 80 | 60 | 100 | 1 | 1.2 | 15 | 20 |
Places of public resort & carparks | 15 | 25 | 45 | 60 | 100 | 80 | 60 | 100 | 1(h) | 1.2(h) | 15 | 20 |
Schools & educational buildings | 15 | 25 | 45 | 60 | 100 | 80 | 60 | 100 | 1 | 1.5(a) | 15 | 20 |
Healthcare facility (inpatient) | 15 | 25 | 30 | 45 | 30 | 30 | 15 | 30 | 1 | 2(b) | 15 | 20 |
Hotels, Boarding Houses, Serviced Apartments, Hostels, Backpackers Hotel, Dormitories | 15 | 20 | 30 | 60 | 60 | 50 | 45 | 50 | 1 | 1.2 | 15 | 20 |
Blocks of flates/maisonettes (k) | 15(g) 20(j) | 30(g) 40(j) | 30 45(j) | 75 | 50 | 40 | 30 | 50 | 1(i) | 1.2 | 15 | 20 |
Detached, semi-detached & terrace house, including townhouses | NR | NR | NR | NR | NR | NR | NR | NR | 0.9 | 0.9 | NR | NR |
Note: NR = No requirements. (x) = Unit of width 500mm (a) = Applies to corridors serving classrooms. Other corridors shall have a minimum width of 1.2m (b) = Applies to corridors serving patients. Other corridors shall have a minimum width of 1.2m (c) = See Cl.2.3.9 (d) = See Cl.2.3.8 | (e) = Where a door opening is divided by mullions into two or more openings, each such opening shall be measured separately in computing the number of units of exit width (f) = See Cl.2.2.15 regarding reduction of exit provision (g) = For travel distance in single staircase flats (see Cl.9.2.1a.(8)) (h) = Refer to Cl.9.7.3a. (i) = Staircase within maisonette serving as an internal access to be at least 900mm width (j) = Applies to external corridor (see Cl.2.3.10) (k) = Measurement of travel distance is from the residential unit door to exit (see Cl.9.2.1a.(5)) (l) = For buildings/ usages/ areas that are exempted from barrier-free accessibility compliance, as required by the authority having jurisdiction on accessibility in the built environment, any corridor solely serving those buildings/ usages/ areas can be reduced to 1m. This is not applicable to Note (a) corridor serving classrooms, Note (b) corridor serving patient wards, and/ or PG I buildings | |||||||||||