Chapter 5 ELECTRICAL POWER SUPPLIES
Chapter 5
ELECTRICAL POWER SUPPLIES
5.1
INSTALLATION
5.1.1
The installation, control and distribution of wiring of electrical
equipment in buildings shall be in accordance with SS CP 5 Code of
Practice for Wiring of Electrical Equipment of Buildings and SS CP 16
Code of Practice for Earthing.
5.2
PRIMARY AND SECONDARY SUPPLIES
5.2.1
Where any of the following installations is required by this Code or
other Codes/Regulations, its primary and secondary source of
power supplies shall comply with the corresponding Code of
Practice stated therein:
Where any of the following installations is required by this Code or
other Codes/Regulations, its primary and secondary source of
power supplies shall comply with the corresponding Code of
Practice stated therein:
Apart from the supply from normal mains, a secondary source of
power supply shall be provided to serve all essential services in the
building when there is a power failure from normal mains. Secondary
source of power supply would come from standby generator set,
which would automatically start, when there is power failure in the
building.
(No illustration)
Atrium smoke control system is required if any building under Purpose
Groups III is designed to incorporate an atrium under cl.7.5 of Chapter 7.
Large basement occupancy other than car park usage shall be provided
with engineered smoke control system, if the gross floor area exceeds 1900
sq m under cl.7.4 of Chapter 7. All smoke control systems shall be
connected to secondary power supply.
Lifts that are commonly found in buildings under Purpose Groups IV, V and
VII are electrical passenger lifts, fire lifts and goods/service lifts.
The current SS CP 2 specifically requires the provision of secondary power
supply to the passenger and fire lifts.
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Where emergency generator is provided, the lifts would be designed to
home to the designated floor under generator power upon loss of normal
power supply.
(b)
Where electrical fire alarm system is required, its primary power
supply as well as type and capacity of battery shall comply
with SS CP 10 Code of Practice for the Installation and
Servicing of Electrical Fire Alarm Systems.
(No illustration)
Electrical fire alarm system (manual or automatic) is required in most
buildings under Purpose Groups III. The electrical fire alarm system shall be
provided with emergency battery supply to the requirement of SS CP 10.
(c)
Where exit or emergency lighting system is required, its
electrical wiring, type and capacity of battery or other form of
secondary power supply shall comply with SS CP 19 Code of
Practice for the Installation and Maintenance of Emergency
Evacuation Lighting and Power Supply Systems in Buildings.
(No illustration)
Emergency lighting in exit staircases and escape routes would need to be
provided with either self-contained battery or connected to secondary
power supply.
(d)
Where an emergency voice communication system is
required, its electrical wiring shall be fire rated or otherwise fire
protected in accordance with SS CP 25 Code of Practice for
Emergency Voice Communication System in Buildings.
Appropriate type and capacity of secondary source of supply
shall also be provided accordingly.
(No illustration)
The current Fire Code 2002 requires emergency voice communication
system to be provided in buildings under Purpose Groups III.
The type and extent of the emergency voice communication shall be in accordance with
cl.8.2 of the Fire Code 2002. Technical requirements such as fire rated cables, routing and
emergency power supply shall comply with SS CP 25.
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(e)
Where a wet rising main system is required, the relevant
electrical supply shall be installed in accordance with SS CP 29
Code of Practice for Fire Hydrant Systems and Hose Reels. A
secondary source of power supply with capacity stipulated in
SS CP 29 shall be provided for the wet rising main pumps.
(No illustration)
Where a building under purpose group III exceeds 60m in habitable height,
wet rising main system shall be provided. The wet riser pump including any
transfer pumps shall be connected to secondary power supply. If electrical
generator is available, the electrical pumps shall be connected to this
source of supply. In the absence of emergency generator set, the
duplicate wet riser pump or transfer pump shall be diesel engine-driven and
shall start automatically when there is demand on the riser main system to
supply water. This is to ensure that the wet riser main system would remain
operational during failure of normal power supply.
(f)
Installation of electrical supply for sprinkler system shall comply
with SS CP 52 Code of Practice for Automatic Fire Sprinkler
System. Capacity of secondary source of supply, where
required, shall satisfy the operation requirements under the
respective hazard category.
(No illustration)
Buildings under Purpose Groups III exceeding 24m in habitable height or
larger than the permitted compartmentation size shall be provided with
automatic sprinkler system complying with SS CP 52.
The sprinkler pump including any transfer pumps shall be connected to
secondary power supply. If electrical generator set is available, the
electrical pumps shall be connected to this source of supply. In the
absence of emergency generator set, the duplicate sprinkler pump or
transfer pump shall be diesel engine-driven and shall start automatically
when there is demand on the sprinkler system to supply water. This is to
ensure that the sprinkler system would remain operational during failure of
normal power supply.
(g)
Secondary source of supply
Mechanical ventilation where required for the following rooms
or spaces shall be provided with secondary source of supply in
accordance with SS CP 13 Code of Practice for Mechanical
Ventilation and Air-conditioning in Buildings:
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(i)
exit staircases and exit passageways;
(ii)
smoke-stop and fire fighting lobbies;
(iii)
areas of refuge within the same building;
(iv)
basement car parks;
(v)
fire command centres;
(vi)
flammable liquid/gas storage rooms.
(No illustration)
Standby source of power supply may be in the form of emergency
generator or uninterruptable power supply. This is to ensure that the
mechanical ventilation system provided to these rooms or spaces would
not be affected during power failure.
(h)
Where mechanical ventilation is installed to provide air for the
operation of the following equipment, secondary source of
supply shall be provided:
(i)
emergency generator;
(ii)
engine driven fire pump.
(No illustration)
If the emergency generator or engine driven fire pump rooms are provided
with mechanical ventilation, the mechanical ventilation system should
continue to function under secondary source of power supply.
5.2.2
The following systems shall be provided with secondary source of
supply:
(a)
Atrium smoke control system, including associated AHU's
forming part of the system.
(b)
All smoke control systems where required by this Code.
(No illustration)
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5.2.3
Emergency generator
Where emergency generators are provided as a secondary source
of supply, they shall comply with SS CP 31 Code of Practice for
Installation,
Operation,
Maintenance,
Performance
and
Constructional Requirements of Mains Failure Standby Generating
Systems.
(No illustration)
Emergency generator shall start automatically upon simulation of power failure
and shall be sufficiently sized to supply power to fire safety systems such as
essential fans, fire pumps & lift system.
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