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Axonometric View

Figure 8.1.1a. - 1

Axonometric View

Figure 8.1.1a. - 2

1. When a fire occurs in a building, the degree of visibility in corridors, staircases and passageways  plays a vital part in facilitating evacuation of occupants.

2. Street lighting should not be relied upon to provide the emergency lighting as they could malfunction or there could be district power failure during an emergency or they could be shaded by trees/building structures. All buildings shall be self-sufficient in the provision of artificial lighting without any reliance on other or external sources.

( No illustration )

SS.563 requires that horizontal illuminance  in the centre line of any escape route shall not be less than 0.5 lux, measured at the floor, for minimum duration of 1 hour.

The positioning of lighting shall be so arranged that the failure of any single lighting unit, such as the burning out of a bulb, will not leave any area in darkness.

Exit areas, such as exit staircases, internal and external exit passageways, are critical areas, there shall be no interruption of illumination exceeding 1 second during the changeover from one energy source to another. This would help ensure the occupants to see their way for example, down the exit staircases without fear of tripping. For ease of reference, the value of 1 foot candle is equivalent to 10 lux, measured at the floor.

Figure 8.1.3a.(1)

Room having a direct distance > 13m and designed with defined escape path shall be provided with emergency lighting.

Figure 8.1.3a.(2)

Room having a direct distance > 13m and not provided with defined escape path or where escape path is not defined, emergency lighting shall be provided to cover the whole floor space. The level of illuminance shall comply with SS 563.

The emergency lighting enable the occupants/maintenance personnel in the mentioned locations to evacuate safely in times of power failure. In addition, the emergency lighting will help firefighters to gain access into any of these rooms or spaces for firefighting or operations purposes.

( No illustration )

Emergency lighting is required to be provided to lift car, generator rooms & fire pump rooms to enable maintenance personnel to evacuate safely in times of emergency. The emergency lighting would help firefighters if there is a need to gain access into any of these rooms or spaces.

Basement car parks are also required to be provided with emergency lighting regardless of the floor area. It would help to lead public to the nearest exit escape routes. Car lighting cannot be taken and relied upon as emergency lighting.

Figure 8.1.7a.(1) : Exit signs to exit on every floor

Decorations, furnishings or equipment, which impair visibility of an exit sign shall not be allowed; nor shall there be any brightly illuminated sign (for other than exit purposes), display or object in or near the line of vision to the required exit sign.

Figure 8.1.7b.(1) - 1

Figure 8.1.7b.(1) - 2

The above show a few variations of the placing of exit / directional signs. Access to exits shall be marked by readily visible signs  in all cases where the exit or way to reach it is not immediately visible to the occupants.  Sign placement shall be such that no point along the exit route is more than 30m from the nearest visible sign.

Figure 8.1.7b.(1) - 3

In factory/warehouse premises, with high storage rack areas ,the vision to exits and directional exit signs may be blocked, hence the signs are shifted or additional signs should be provided to help occupants to evacuate in times of emergency.

Figure 8.1.7b.(1) - 4

In shopping centre/institutional occupancy areas, exit directional signs are to be placed at strategic locations so that members of public/shoppers could rely on the signs to evacuate in times of emergency.

Low level or floor-mounted signs are not intended to replace standard exit signs but are designed to aid building occupants to get to the exits should smoke obscure the exits and exit directional signs mounted at above door height.

Figure 8.1.7c. : Low level signs

This requirement is mandatory for hotel usage, although it is not applicable to public resort occupancies, it would be a good practice to have it.

1. Such signs strategically located in the common corridor would help the occupants to find their way to the floor exits should smoke obscure the exits & exit directional signs normally mounted at above door height.

2. Low-level or floor mounted signs are not intended to replace standard exit signs but are designed to aid building occupants to get to the exit in a smoke-filled environment.

3.The bottom of the low-level sign shall be not less than 150mm or more than 200mm above the floor level.  It shall be placed at not more than 10m interval. For exit doors, the sign shall be on the door or adjacent to the door with the closest edge of the sign within 100mm of the door frame.

The purpose of providing signage within exit staircases is to prevent  occupants from travelling beyond the discharge level into the basement. The signage helps to inform occupants in the exit staircase enclosure on the level of exit discharge to the safe external space.

Figure 8.1.7d.(1) - 1

This can be done by placing a physical barrier to prevent occupants from continuing below the level of exit discharge into the basement. This helps to warn occupants in the staircase enclosure that they are on the level of exit discharge.

Cl.2.3.5d. allows upper storey staircase to be continuous with that serving the basement, which is naturally ventilated.

To prevent occupants exiting continuously from upper storeys into the basement floor during an emergency, a physical barrier in the form of a door or a gate (as shown above) could be provided across the staircase landing at ground level to separate the discharge route of upper storeys from the basement staircase.

In addition, appropriate signage should be provided inside the staircase enclosure to direct occupants out of the building at ground level.

Applicable to staircase serving more than 4 storeys inclusive of basement.

Figure 8.1.7d.(1) - 2

Viewing distance is derived as follows:

I = z₀h, where I (m) is the viewing distance; z₀ is the distance factor with observation position normal to the centre of the pictogram /‘EXIT’ legend, and h (m) is the height of pictogram / ‘EXIT’ legend

With the withdrawn of BS 5499 Part 2, all self-illuminating exit and  directional signs powered by radioactive materials shall comply and tested to the testing standard UL 924. For radioactive materials to be permitted, such material shall meet the minimum 50 lux illuminance. Where the minimum 50 lux illuminance is not achievable, such signs shall be externally lit by a nearby emergency luminaires.

Figure 8.1.8b. - 1 : Photo luminescent nose strip at the leading edge of stair riser

The strip shall be at least 50mm in width and to be placed at the leading edge of each stair rise.

Figure 8.1.8b. - 2

Figure 8.1.8b. - 3

In designated corridor with exit directional sign.

Applicable to building with fixed corridor leading to exit staircase, except hotel guest room floor where low level electrical exit directional sign is mandatory.

Photo luminescent exit directional sign with the word “EXIT” or Exit legend as per SS 508 and directional arrow with green ground printed on the surface or silk screened on reverse surface, along one side of the walls of the designated corridor. For long corridor, the photoluminescent exit directional sign shall be affixed at not more than 10m interval. Additional sign would be required at junctions.

The wall affixed sign shall be at least 300mm long and 150mm wide and be placed not less than 150mm or more than 400mm from the lobby landing level. Depending on the length and configuration of the designated corridor, numerous number of signs to be provided on one side of the walls with directional arrow pointing towards the exit direction within designated corridor.

Figure 8.1.8b. - 4