Explanations & Illustrations

Clause 1.4.2 : Air well

( No illustration )

The minimum air well size specification in Table 1.4.2 is intended for exit staircase ventilation via an external space that is within an air well situation. To qualify as external space, the air well size shall comply with Table 1.4.2 and air well shall be devoid of any overhead obstruction such as trellis over the air well as it may have an adverse effect on smoke ventilation.

Readers should not confuse the ventilation requirements for smoke-stop lobby with that for exit staircase where the air well size differs. To qualify as external space under Cl.2.2.13a.(3), the air well size shall have minimum width 6m and a superficial plan area of not less than 93m². However, in the case of exit staircase ventilation via an air well, the minimum clear width of the air well is 10m.

Explanations & Illustrations

Clause 1.4.5 : Ancillary Usage

Figure 1.4.5

The office is “supporting” the activities at the factory production area. If the office is rented to other tenant & having activities that is not supporting the activities at the production area, it is not considered as ancillary office.

Explanations & Illustrations

Clause 1.4.8 : Area of Compartment/Room/Space

Figure. 1.4 8 - 1

Measurement of area of room

Section

Figure. 1.4.8 - 2

Measurement of area for building without external wall

Explanations & Illustrations

Clause 1.4.9 : Area of refuge

Section a - a

Figure 1.4.9 - 1

For building A to qualify for reduction in the provision of exits, adjoining building B must act as an area of refuge.

Note : The area of refuge is a temporary holding area. Hence the staircases provided need not be designed to accommodate all the people that will occupy the area of refuge in case of emergency.

Figure 1.4.9 - 2

An area in an adjoining part of the same building may act as an area of refuge.

Figure 1.4.9 - 3 : Acceptable proposal

It is acceptable for compartment B to act as an area of refuge for compartment A or vice versa as the access is through an open sided corridor.

Figure 1.4.9 - 4 : Not acceptable proposal

Compartment B is acting as an area of refuge to compartment A which is not meeting the intent of the Fire Code, hence not acceptable.

Note : It is critical that the area of refuge shall be accessible to evacuees in times of emergency. Where there is doubt that evacuees would not be able to gain access to the area of refuge owing to locking of doors and different tenancies, the concept of area of refuge would not work.

Explanations & Illustrations

Clause 1.4.10 : Area of Roof

Left Figure : Elevation
Right Figure : Axonometric view
Area of roof = 2(L x W)

Figure 1.4.10

Roof area computation

Explanations & Illustrations

Clause 1.4.11 : Area of Storey

Figure 1.4.11

Storey area computation

Explanations & Illustrations

Clause 1.4.12 : Assembly occupancy

( No Illustration )

Not all buildings or portions of buildings used for assembly occupancy of more than 50 persons are considered as public building. Cl.1.4.84 defines “public building” as those buildings or part thereof used or constructed or adapted to be used as a shop, office, hospital or place of public resort, not being a church, chapel, mosque, temple or other place where public worship is or religious ceremonies are performed.

Assembly occupancy could be found in other purpose groups other than places of public resort, for example auditorium in office building, lecture theatre in school/institution, etc..

Explanations & Illustrations

Clause 1.4.13 : Atrium

Sectional view

Figure 1.4.13 - 1

Although atrium is defined as openings connecting 2 or more storeys, the requirements stipulated in Cl.3.2.6. is only applicable when the atrium is more than 3 storeys.

Section

Figure 1.4.13 - 2

The entire floor area of the interconnected space is open and unobstructed such that a fire in any part of the space will be readily obvious to the occupants of the space prior to the time it becomes a hazard to them.

Explanations & Illustrations

Clause 1.4.15 : Basement storey

Section

Figure 1.4.15 - 1

Section

Figure 1.4.15 - 2

Building built on slope and partially covered by surrounding ground

Section

Figure 1.4.15 - 3

Building with no ground level

Axonometric view

Figure 1.4.15 - 4

As Y1+Y2+Y3+Y4 > X1+X3, this level is considered as a basement

Explanations & Illustrations

Clause 1.4.17 : Boundary

Axonometric view

Figure 1.4.17 - 1

Buildings that are directly fronting or abutting a public street, canal or river can have the facade unprotected opening measuring up to the centre of the public street, canal or river.

Figure 1.4.17 - 2

With regard to compliance of unprotected openings of the building that abuts a public street, it can be measured to the centre of public street instead of lot boundary.

Explanations & Illustrations

Clause 1.4.18 : Cavity barrier

Section

Figure 1.4.18 - 1

Concealed ceiling space without cavity barrier

Section

Figure 1.4.18 - 2

Concealed ceiling space with cavity barrier

Section

Figure 1.4.18 - 3

Concealed floor space without cavity barrier

Section

Figure 1.4.18 - 4

Concealed floor space with cavity barrier

Explanations & Illustrations

Clause 1.4.19 : Ceiling

Section

Detail A

Figure 1.4.19 - 1

Axonometric Section

Figure 1.4.19 - 2

Soffit and roof light (skylight) is included as part of the ceiling surface, but not the frame of the roof.

Explanations & Illustrations

Clause 1.4.20 : Circulation Space

Figure 1.4.20

In general, circulation space refers to common corridors, lobbies, etc.. It is a common area for access of occupants from a room to an exit. Such common areas are normally separated from other area with partition/walls.

(Note that car park cannot be deemed as circulation space)

Explanations & Illustrations

Clause 1.4.21 : Code of Practice

( No illustration )

It includes all subsequent amendments that may be issued by the SCDF. Examples of Codes of Practice or Standards that are acceptable to the SCDF are :

(a) Singapore Standards Codes of Practice

(b) British Standards Codes of Practice

(c) Australian Standards

(d) National Fire Prevention Association (NFPA) 130

For buildings which have been approved based on earlier Code of Practice for Fire Precautions in Buildings, the SCDF may consider applying the latest version to all new Additions and Alterations or Extension of works.

Explanations & Illustrations

Clause 1.4.23 : Compartment

Figure 1.4.23 - 1

Section

Figure 1.4.23 - 2

Sectional view

Figure 1.4.23 - 3

Explanations & Illustrations

Clause 1.4.24 : Compartment Wall & Compartment Floor

Section

Figure 1.4.24

Explanations & Illustrations

Clause 1.4.26 : Concealed Space (Cavity)

See explanation & illustration for Clause 1.4.18

Explanations & Illustrations

Clause 1.4.27 : Corridor

Figure 1.4.27 - 1

Internal corridor

Figure 1.4.27 - 2

Internal corridor + External corridor

Figure 1.4.27 - 3

External corridor

Explanations & Illustrations

Clause 1.4.31 : Dead-end

Figure 1.4.31 : Dead-end

Explanations & Illustrations

Clause 1.4.32 : Direct distance

Figure 1.4.32 - 1 : Direct distance

“Direct Distance” means the shortest distance from any point within the floor area, measured with the external enclosures of the building, to the relevant exit ignoring walls, partitions and fittings other than the enclosing walls/partitions to protected staircases.

Figure 1.4.32 - 2 : Travel distance

“Travel Distance” means the actual distance to be travelled by a person from any point within a floor area to the relevant exit having regard to the layout of walls, partitions, fixtures and fitting.

Explanations & Illustrations

Clause 1.4.34 : Electro-magnetic/mech door-holding device

See explanation/illustration for clause 1.4.35

Explanations & Illustrations

Clause 1.4.36 : Element of structure

Section

Figure 1.4.36

For building A the pitched roof is not considered as part of the structural frame of the building. However, the RC slab and beam supporting the pitched roof are considered elements of structures as they help to carry the dead load imposed by the pitched roof. For building B the RC roof is not considered as an element of structure. However, the beams supporting the RC roof are considered to be elements of structure of the building.

The columns supporting the pitch roofs are not element of structure as they are not part of the column supporting the whole building. Hence the columns only need to be constructed of non-combustible material.

Explanations & Illustrations

Clause 1.4.42 : Exit access

Figure 1.4.42 - 1

Door A = exit doors

Door B, C & D = exit access doors

Exit access door shall comply with all the requirements of an exit door and need not have fire resistance rating, unless it is specified.

Figure 1.4.42 - 2

Figure 1.4.42 - 3

The layout is not acceptable.

The clear width of the exit door opening is less than 850mm and the door is opened at an angle of less than 90 degree.

Figure 1.4.42 - 4

Exit doors which open into the common corridor should not cause obstruction to movement of occupants

Figure 1.4.42 - 5

Exit doors which cause obstruction when open into the common corridor shall recessed

Explanations & Illustrations

Clause 1.4.43 : Exit access door

Explanations & Illustrations

Clause 1.4.44 : Exit door

Explanations & Illustrations

Clause 1.4.45 : Exit passageway

Figure 1.4.45 - 1

Horizontal extension of vertical exit

Figure 1.4.45 - 2

Exit passageway at 1^st storey

Explanations & Illustrations

Clause 1.4.46 : Exit staircase

Axonometric Section

Figure 1.4.46 - 1

Alternative method of protecting stairway enclosures

Axonometric Section

Figure 1.4.46 - 2

Where the stairway enclosure projects beyond the external wall of the building and is connected thereto, then either:

(a) the external wall or wall of any part of the building less than 3m from the stairway enclosure, or

(b) the external wall or walls of any part of the stairway enclosure within any 3m from the building should be imperforate and of not less than one hour fire resistance.

Axonometric Section

Figure 1.4.46 - 3

Accommodation or access staircases are provided solely for the convenience of moving easily and quickly from one floor to another are not considered as exit staircases.

Figure 1.4.46 - 4

Internal exit staircases are required to be provided with masonry enclosures and mechanical ventilation. Masonry enclosures to internal exit staircases, mechanical ventilation is to be provided. Where the building exceeds 24m in habitable height, the staircases are to be pressurised.

All exit staircases are considered as protected shafts are required to be separated from other areas by masonry walls to have the necessary fire resistance rating required by Cl.3.3 for elements of structure for the part of the building in which they are located. Thus, the enclosures to staircases serving the basement would have higher fire resistance rating than that of staircases serving upper storeys. Door opening into the exit staircase shall have min. ½-hr fire resistance rating.

Explanations & Illustrations

Clause 1.4.48 : External exit passageway

Figure 1.4.48 : External exit passageway

External exit passageway is an extension of the vertical exit. It is considered a protected area to allow occupants the safe egress. There is no control on the numbers of doors opening into an external exit passageway.

Explanations & Illustrations

Clause 1.4.51 : External wall

Section

Figure 1.4.51 : External wall

Where that part of roof is treated as an external wall in accordance with the above definition, it shall comply with Cl.3.5 on the permitted limit of unprotected areas and the surface flame spread requirements. See also Cl.1.4.108 for the meaning of “unprotected areas”.

Explanations & Illustrations

Clause 1.4.53 : Fire lift lobby

Figure 1.4.53 : Fire lift lobby

The lobby floor shall be graded from the lift landing door towards the lobby door with a fall not exceeding 1: 200 to prevent water from flowing into the lift shaft. The lobby provides a buffer zone to prevent smoke from streaming into the protected staircase. The lobby acts as a staging area for fire fighters in carrying out firefighting operation. There is a need to limit the size to max. 10m² to prevent the space being used for other purposes. For mechanical ventilation requirement, see Cl.7.1.10

Explanations & Illustrations

Clause 1.4.54 : Fire resistance

Figure 1.4.54 : Fire resistance

Fire resistance is a property, currently measured in BS 476: part 20 to 23 furnace test, of a particular element of building construction (it is not a property of a building material) and is the measure of its ability to satisfy for a stated period in minutes some or all of the following criteria:

(a) Stability - resistance to collapse or excessive deflection

(b) Integrity - resistance to passage of flames and hot gases

(c) Insulation - resistance to excessive temperature rise on exposed face

Explanations & Illustrations

Clause 1.4.56 : Fire stop

Axonometric Section

Figure 1.4.56 - 1 : Wall penetration details

Section

Figure 1.4.56 - 2 : Floor penetration details

To avoid weakening of the fire-rated wall/floor, openings for service penetration should be :

(a) kept as few in number as possible;

(b) as small as practicable; and

(c) all gaps shall be filled with fire-stopping materials.

Section

Figure 1.4.56 - 3 : Curtain wall detail

It is important that the gap between the edge of the structural floor slab and the curtain wall should be fire stopped to prevent migration of smoke and flame from floor to floor

Axonometric Section

Figure 1.4.56 - 4 : Cable trucking

Explanations & Illustrations

Clause 1.4.58 : Flexible joints & flexible connections

Axonometric view

Figure 1.4.58- 1 : Flexible joint

Flexible joints shall not exceed 250mm in length and be made of materials classified as “not-easily-ignitable” when tested under BS 476 Pt. 5

Axonometric Section

Figure 1.4.58 - 2 : Flexible connection

Flexible connection material shall have a surface flame spread rating of not lower than Class ‘1’. However, in areas of building where Class ‘0’ flame spread rating is required for the ceiling construction under the Fire Code, a Class ‘0’ rating for the covering and lining materials shall be required. Flexible connection shall not exceed 4m in length. It shall not pass through fire resisting walls, floors or partitions and when involved in fire generates a minimum amount of smoke and toxic gases.

Explanations & Illustrations

Clause 1.4.65 : Height of building

Section

Figure 1.4.65 - 1

Average ground level to half the vertical height of the pitch roof

Section

Figure 1.4.65 - 2

Average ground level to flat roof and the top of walls of parapet

Section

Figure 1.4.65 - 3

Average ground level to half the vertical height of the pitch roof of a part of a building

Explanations & Illustrations

Clause 1.4.71 : Non-combustible material

( No illustration )

Material can also be considered as non-combustible or limited combustibility achieving Class “A1” or “A2” in accordance with EN 13501 classification.

Explanations & Illustrations

Clause 1.4.73 : Notional boundary

Section

Figure 1.4.73 - 1 : Notional boundary between 2 tower blocks, either sitting on podium deck or ground level

Section

Figure 1.4.73 - 2 : Notional boundary between a warehouse and factory sited within a development plot of land bounded by common boundaries

The extent of unprotected openings e.g. windows in the external wall of a building is controlled by the space separation between the building and the boundary. The greater the building setback, the higher the extent of unprotected openings that would be allowed in the external wall. This is to address the concern of spread of fire from one building to another. The use of the boundary instead of another building makes it possible to work out the extent of unprotected openings even where another building does not exist.

In some situations, the distance to other building on the same site needs to be considered to prevent spread of fire. This is done by assuming a boundary called notional boundary. A notional boundary should be so situated that all buildings comply with the safe distance requirements as annotated in X and Y in the above diagrams. The boundary, which a wall faces (at an angle of 80º C or less) whether it is the boundary of the site or a notional boundary is called the relevant boundary.

In the diagram, if the total setback distance for warehouse and factory is more than or equal to X + Y, then the setback distance is considered complied with provided that both buildings are within the same lot.

Explanations & Illustrations

Clause 1.4.75 : Occupant load

( No illustration )

(a) Table 1.4B gives a range of occupant load factors. To calculate the occupant load of a floor space for example an office, apply the formula:

Occupant load
= Floor area office (1000m²) / Occupant load factor for office (10m²)
= 1000m² / 10m²/person
= 100 persons

(b)

(i) The occupant load for theatre or cinema where there is fixed seating, the posted occupant load based on number of seats can be taken.

(ii) The back stage areas shall be separately calculated based on floor area.

(iii) Where there are spaces provided for flexible seating, the occupant load for these spaces shall be separately calculated based on floor area.

Explanations & Illustrations

Clause 1.4.79 : Permitted limit of unprotected area

Section

Figure 1.4.79 : Permitted limit of unprotected area

The main concern of unprotected openings in external walls is to ensure that spread of fire through heat radiation from one building to another would be minimised. However, Cl.3.5.3 does permit relaxation for buildings, which are sprinkler-protected or solely used as car parks.

Explanations & Illustrations

Clause 1.4.81 : Private lift

Figure 1.4.81 : Private lift

Emergency power supply from a generating plant shall be provided to home the privates lifts to the designated/alternate designated floor during a power failure or fire emergency in the building. See Cl.3.8.8h. for more information.

Explanations & Illustrations

Clause 1.4.82 : Protected shaft

Axonometric Section

Figure 1.4.82 : Protected shaft

Explanations & Illustrations

Clause 1.4.83 : Protected structure

Section

Figure 1.4.83 : Protecting structure

There is a need to differentiate protecting structure to shaft from other elements of structures such as compartment walls, separating walls and external walls. This is for the purpose of working out differently the necessary period of fire resistance rating to the protecting structures. For example, Cl.3.8.6 permits door to protected shaft to have ½ the period of fire resistance rating of the enclosing protecting structures to an exit staircase.

Explanations & Illustrations

Clause 1.4.85 : Purpose Group

(a) For the purpose of complying with fire safety requirements under this Code, every building or compartment shall be treated according to its use or intended use as prescribed under Table 1.4A.

(b) Flatted factory building

Section

Figure 1.4.85

Each floor is a compartment with 6th storey being further divided into 2 compartments, having 40% office and 60% factory use. The main purpose of use of 6th storey is factory, thus 6th storey is to be treated as factory use. Similarly, a building may have shops, offices and restaurants, but it is classified as shopping centre as the main purpose of use of the building is shopping.

(c) Townhouses

Under the Fire Safety (Exemption) order, proposal for detached, semi- detached, terraced and linked houses which do not exceed 3 storeys or levels, including basement or attic are not required to be submitted to the SCDF for approval. The Qualified Person in charge of the project shall self-regulate to ensure that all relevant fire safety requirements are complied with on site. However, townhouses, which are treated as under PG I for the purpose of complying with fire safety requirements that are applicable to detached, semi-detached terraced and linked houses, are not covered by the Fire Safety (Exemption) Order, hence, submission of plans to the SCDF is required.

(d) Serviced apartments/maisonettes

Serviced apartments/maisonettes would be treated as hotels or boarding houses under PG VII at the outset. However, the SCDF may consider to reclassify it under PG II if the floor layout of the units and escape corridors is similar to that of a typical apartments/maisonettes building.

Explanations & Illustrations

Clause 1.4.87 : Relevant boundary

Section

Figure 1.4.87 : Relevant boundary

The boundary which a side or external wall of a building faces whether it is the boundary of the site or a notional boundary is called the relevant boundary.

Explanations & Illustrations

Clause 1.4.88 : Remoteness of exits

Incorrect

Figure 1.4.88 - 1

Incorrect : Access to the protected staircases will be blocked by a fire occurring in the vicinity of the staircase.

Correct

Figure 1.4.88 - 2

Correct : Access to an alternate staircase is available if a fire occurred in the vicinity of the exit door to one of the staircases.

Explanations & Illustrations

Clause 1.4.89 : Roof light

Top Figure : Section

Middle Figure : Axonometric Section

Bottom Figure : Axonometric view

Figure 1.4.89 : Roof light

Rooflights are part of roof coverings, which permit light to enter a building to provide natural lighting. Rooflights could be designed to be openable by automatic devices to provide the necessary openings for smoke venting. The inner surface of dome light and skylight is considered as ceiling for the purpose of meeting the class of surface flame spread under Cl.3.13.5b..

Explanations & Illustrations

Clause 1.4.90 : Room

Figure 1.4.90 - 1 : Enclosed space

An enclosed space not considered as a room. This includes exit staircase (protected shaft), enclosed circulation space such as A/C, MV shafts, pipe/cable shafts and accessible electrical ducts not exceeding 750mm in depth.

Figure 1.4.90 - 2 : Electrical riser

An electrical riser having a depth of >750mm is considered a room.

Explanations & Illustrations

Clause 1.4.92 : Separated part (of a building)

Section

Figure 1.4.92 : Separated part of a building

Explanations & Illustrations

Clause 1.4.93 : Separating wall

Axonometric view

Figure 1.4.93 : Separating wall

Explanations & Illustrations

Clause 1.4.96 : Smoke-check door

Figure 1.4.96 : Smoke-check door

The provision of smoke-check door is applicable to hotel occupancy. It is provided to subdivide the internal corridor to the hotel guest rooms floor into the following lengths:

(a) Building protected by sprinkler system --- 45m

(b) Building not protected by sprinkler system --- 30m

Internal corridors which are not naturally ventilated shall be subdivided by smoke barrier and smoke-check door to prevent the whole corridor being filled with smoke very quickly should there be any migration of smoke from any guestroom. Smoke-check door is not required to have fire resistance rating.

Explanations & Illustrations

Clause 1.4.97 : Smoke-stop lobby

Axonometric view

Figure 1.4.97 : Smoke-stop lobby

If smoke which finds its way into the smoke-stop lobby, the natural ventilation provided by the window will help to prevent the smoke from infiltrating into the protected staircase. In the case of mechanical ventilated smoke-stop lobby, smoke will be prevented from entering the lobby by the exertion of air pumped into it by the air shaft.

Explanations & Illustrations

Clause 1.4.101 : Tenancy unit

Figure 1.4.101 : Tenancy unit

Explanations & Illustrations

Clause 1.4.105 : Travel distance

Figure 1.4.105 - 1

Measurement starts at 400mm from enclosure of wall.

Figure 1.4.105 - 2

Travel distance from the most remote point to open exterior space. Travel distance shall be measured to the door of the exit staircase i.e. from point A to B.

Figure 1.4.105 - 3

Travel distance from the most remote point to an external exit passageway (i.e. from point A to B).

Explanations & Illustrations

Clause 1.4.108 : Unprotected area

Elevation

Figure 1.4.108 : Unprotected area

Explanations & Illustrations

Clause 1.4.109 : Vertical exit

Section

Figure 1.4.109 : Vertical exit

The protecting structure, excluding external wall of exit staircase or exit ramp shall be constructed of masonry.

Explanations & Illustrations

Clause 1.4.110 : Wall surface

Top Figure : Includes

Bottom Figure : Excludes

Figure 1.4.110 : Wall surface

Explanations & Illustrations

Clause 1.4.111 : Workers' dormitories

Figure 1.4.111

Owing to different uses and risks, cooking is not allowed in the dormitory, which is meant for resting and sleeping. All cooking activities shall be carried out in the kitchen. This will eliminate the risk of fire occurring in any dormitory arising from cooking activities.