The NICEIC Technical Helpline receives many calls on the subject of emergency lighting and fire alarms. Here, we will try to answer a few of the more common questions that are asked.
The NICEIC Technical Helpline receives many calls on the subject of emergency
lighting and fire alarms. Here, we will try to answer a few of the more common
questions that are asked.
Emergency Lighting
1. What reference information is available?
The principle document covering emergency lighting is British Standard 5266
Code of Practice for the emergency lighting of premises other than private domestic
premises, cinemas and certain other special premises used for entertainment.
The code gives recommendations for the indication and illumination of escape
routes in the event of failure of the normal supply, and proposes minimum continuous
periods of operation of emergency lighting based on size, type and usage of
the premises.
British Standard BS EN 1838 Lighting Applications - Emergency Lighting also
applies. This standard specifies the luminous requirements for emergency lighting
systems installed in premises or locations where such systems are required.
It is principally applicable to locations where the public or workers have access.
The following ICEL publications are also applicable:
ICEL 1001 Product and authenticated photometric data registration scheme
ICEL 1004 The use, or modification of mains luminaires for emergency lighting
applications
ICEL 1006 Emergency lighting design guide
ICEL 1008 Emergency lighting risk assessment guide
ICEL 1009
Central battery standard and registration scheme
2. How do I establish whether emergency lighting should be provided, and what
are the requirements that have to be met?
Consultation between the owner and/or occupier of the premises, the architect,
the installation contractor, the electricity authority and any others concerned
should be arranged at an early stage. It is also important the requirements
of any national and/or local legislation which may apply to the premises in
question are fully recognized and discussed at this time.
3. What are maintained and non-maintained emergency lighting systems?
A maintained emergency lighting is a system in which all emergency lamps are
in operation at all times. A non-maintained emergency lighting is a system in
which all emergency lighting lamps are in operation only when the supply to
the normal lighting fails.
4. What are the categories of emergency lighting?
Any emergency lighting system may be design to supply the required load for
any desired time. However, for most applications, it is considered that a duration
of between 1 and 3 hours should meet all normal requirements. In the Code of
Practice BS 5266, emergency lighting systems are categorized by the prefix 'M'
for maintained and 'NM' for non-maintained systems, followed by a '/' and the
number of hours duration claimed for the installation e.g M/1 is a maintained
1h duration system.
5. Which category of system should be adopted?
The type and category of system to be used is dependent upon the size and function
of the premises. For many types of premises, there are statutory requirements
relating to emergency lighting, and it is important that the appropriate authority
is consulted. However, for most applications it is considered that a duration
of between 1 hour and 3 hours should meet all normal requirements.
A maintained mode of operation should always be used in premises where the
normal lighting can be dimmed or reduced below the levels required for escape
route identification and illumination, while the premises are occupied. In all
other premises, a non-maintained mode of operation may be suitable. BS 5266
gives detailed examples of situations with the correct category to be adopted.
6. What is required in the way of certification and/or log book?
On completing the installation of an emergency lighting system, or part of
it, or of a major alteration to an existing installation, an emergency lighting
completion certificate should be supplied to the occupier/owner of the premises.
A copy of this certificate may be required by the enforcing authority.
On completion of a three-yearly inspection and test schedule, an emergency
lighting periodic inspection and test certificate should be issued to the occupier/owner
of the premises. This certificate should be supplied at intervals of no more
than 3 years or on the completion of a major alteration or addition to an existing
installation, or at such other times as required by the enforcing authority.
A copy of this certificate may be required by the enforcing authority.
A log book should be kept on the premises in the care of a responsible person
appointed by the occupier/owner and should be readily available for examination
by any authorized person. The log book should be used to record the following
information:
a) Date of any completion certificate including any certificate relating to
alterations.
b) Date of each periodic inspection and test certificate.
c) Date and brief details of each service, inspection or test carried out.
d) Date and brief details of any defects and of remedial action taken.
e)
Date and brief details of any alterations to the emergency lighting installation.
Fire Alarms
1. Which British Standards give requirements for fire alarm detection and
fire alarm systems and what areas do they cover?
The principle British Standards giving requirements for the installation of
fire alarm systems are BS 5839 Parts 1 and 6.
BS 5839 Part 1 is dated 2002 and gives recommendations for the planning, design,
installation, commissioning and maintenance of fire detection and fire alarm
systems in and around buildings other than dwellings. It does not, however,
recommend whether or not a fire alarm system should be installed in any given
premises.
BS 5839 Part 1 is entitled: Fire detection and fire alarm systems for buildings.
It is the Code of Practice for system design, installation, commissioning and
maintenance. In BS 5839, the term fire detection and alarm systems includes
systems that range from those comprising only one or two manual call points
and sounders to complex networked systems that incorporate a large number of
automatic fire detectors, manual call points and sounders, connected to numerous
inter-communicating control and indicating panels. The term also includes systems
that provide signals to initiate the operation of other fire protection systems
and equipment (such as fire extinguishing systems, smoke control systems or
automatic door release equipment) or safety measures (such as shut down of air
handling systems or grounding of lifts). It does not apply to the other systems
and equipment themselves or the circuits that interface with them.
These parts of BS 5839 do not cover systems which extinguish or control fires,
such as sprinkler or automatic extinguishing systems. They do cover the use
of a signal from an automatic extinguishing system as one initiating element
of a fire alarm system (e.g. by use of a pressure of flow switch).
Parts 1 and 6 do not cover voice alarm systems, 999 public emergency call systems,
manually or mechanically operated sounders, or systems combining fire alarm
functions with other non-fire related functions.
BS 5839 Part 6 is dated 1995 and is entitled: Fire detection and alarm systems
for buildings. It is the Code of Practice for the design and installation of
fire detection and alarm systems in dwellings. Part 6 gives recommendations
for the planning, design and installation of fire detection and alarm systems
in dwellings. The recommendations apply to both new dwellings and existing dwellings.
The systems covered in this part range from those comprising a single self-contained
smoke alarm to the fire detection components of combined domestic fire and intruder
alarm systems or fire alarm systems.
Part 6 applies to forms of dwelling including bungalows, multi-storey houses,
individual flats and maisonettes, mobile homes, sheltered houses, NHS housing
in the community and houses divided into several self-contained single-family
dwelling units. This part is intended for use by architects, enforcing authorities,
contractors and others responsible for implementing fire precautions.
The remainder of the BS 5839 series of standards consists of:
Part 2 Fire detection and alarm systems for buildings. Specification for manual
call points
Part 3 Fire detection .... Specification for automatic release mechanisms for
certain fire protection equipment.
Part 4 Fire detection .... Specification for control and indicating equipment
Part 5 Fire detection .... Specification for optical beam smoke detectors
Part 8 Fire detection .... Code of practice for the design, installation and
servicing of voice alarm systems.
How do I establish if a particular building needs a fire alarm system?
The need for a fire alarm system in any specific building will normally be
determined by the authority responsible for enforcing fire safety legislation
in that building and/or by a fire risk assessment carried out by the owner,
landlord, occupier or employer, as appropriate. In general, it is appropriate
to install some form of fire alarm system in virtually all buildings, other
than very small premises that are relatively open-planned so that any fire will
be quickly detected.
Manual fire alarm systems are often sufficient to satisfy legislation in workplaces
in which no one sleeps. Automatic fire detection is usually required by legislation
to supplement the manual system in premises in which people sleep. Automatic
fire detection may also be necessary to satisfy legislation under the following
circumstances:
a) where the automatic fire detection forms part of a fire engineering solution;
b) where fire protection systems, such as door closing facilities or smoke control
systems, are to be operated automatically in the event of fire;
c) where the low level of occupancy of a building is such as to create the potential
for fire to prejudice the means of escape by occupants before they are aware
of the fire.
Automatic fire detection is also commonly used to protect property by ensuring
the early attendance of the fire service. Automatic fire detection systems might
be required or recommended by the property insurers. The early detection of
fire by automatic means and rapid summoning of the fire service, is also important
in premises in which people cannot readily be evacuated in the event of a fire
(e.g. hospitals)
3. What are the categories of fire alarm system?
Fire alarm systems may be installed in buildings to satisfy one or both of
two objectives - protecting life and protecting property. Other possible objectives
exist, such as protection against business interruption and protection of the
environment. Because of the variety of applications, systems are divided into
a number of different Categories:
Category M These are manual systems and incorporate no automatic fire detectors.
Category L
Category L systems are automatic fire detection systems intended for the protection
of life. They are subdivided into:
a) Category L1: systems installed throughout all areas of the building.
b) Category L2: systems installed only in defined parts of the building
c) Category L3: systems designed to give a warning of fire at an early enough
stage to enable all occupants, other than possibly those in the room of fire
origin, to escape safely.
d) Category L4: systems designed to give a warning of fire at an early enough
stage to enable all occupants, other than possibly those in the room of fire
origin, to escape safely.
e) Category L5: systems in which the protected area and/or the location of detectors
is designed to satisfy a specific fire safety objective (other than that of
a Category L1, L2, L3 or L4 system)
Category P
Category P systems are automatic fire detection systems intended for the protection
of property. They are further subdivided into:
a) Category P1: systems installed throughout all areas of the building.
b) Category P2: systems installed only in defined parts of the building
4. For a dwelling, where should smoke detectors be installed?
The presence of smoke in escape routes is the greatest impediment to safe escape
in the event of fire. It is essential that any fire that starts in a circulation
area, or smoke that spreads into a circulation area, be detected as early as
possible. Smoke detectors should therefore be installed in the circulation areas
of all dwellings.
5. How should the fire alarm system in a building be electrically supplied?
The mains supply final circuit to all parts of the fire alarm system should
be dedicated solely to the fire alarm system, and should serve no other systems
or equipment. The circuit should be derived from a point in the building's electrical
distribution system close to the main isolating device for the building.
Every isolator and protective device that can isolate the supply to the fire
alarm system, other than the main isolator for the building, should be labelled:
Fire Alarm In the case of a protective device that serves only the fire alarm
circuit, but incorporates no switch;
Fire Alarm. Do not switch off. Where fire protection systems, such as door
closing facilities or smoke control systems, are to be operated automatically
in the event of fire;
Fire Alarm. This switch also controls the supply to the fire alarm system.
In the case of any switch that disconnects the mains supply to both the fire
alarm system and to other circuits.
Every isolator, switch and protective device that is capable of disconnecting
the mains supply to the fire alarm system should be situated in a position inaccessible
to unauthorized persons or be protected against unauthorized operation by persons
without a special tool. The circuit supplying the fire alarm system should not
be protected by an RCD unless this is necessary to comply with the requirements
of BS 7671. Where an RCD is necessary for electrical safety, a fault on any
other circuit or equipment in the building should not be capable of resulting
in isolation of the supply to the fire alarm system.
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