Fire Safety Equipment

Fire Alarm systems – an overview

Current fire safety legislation;
[Article 13 (1) of the Regulatory Reform (Fire Safety) Order 2005 (the Order)],

states that it is a requirement that the Responsible Person for any premises considers what measures they may need to put in place for the appropriate detection of fire and the subsequent giving of a warning to persons in all parts of the building

so as to alert them to the presence of a dangerous situation.

It is important to remember that premises will differ from each other both in size and usage,

therefore a number of different solutions will exist and each premises needs to be dealt with as a unique entity.

Not every building requires a fire alarm in the conventional sense of the term “fire alarm” as being an electrical system that uses fire detectors, sounders and call points.

However, every building needs a means of giving warning in case of fire.

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In certain instances the fire alarm could effectively consist of air horns or whistles, provided that all persons in the premises knew what the signal meant.

Indeed in very simple buildings a shout of “Fire!” may be the only solution that is required for and no other warning system would be needed.

Fire Alarm situation examples:

In order to further explain this concept please consider the following examples:

warningincaseoffire2

Question

Consider a small business which has only 3 employees all of whom work in a single warehouse unit which is 10m x 10m in size, the unit consists of a single workspace which has 2 exit doors, opposite to each other and both are fully visible from all parts of the room. Does this unit need a fire alarm?

Answer

Current fire safety legislation
[Article 13 (1) of the Regulatory Reform (Fire Safety) Order 2005 (the Order)]
says that there must be sufficient measures in place to detect and give warning of fire; in this case it will be the staff who would detect a fire as all parts of the room are visible.

If all staff are told to shout “fire” they will all be made aware of the need to evacuate as no persons would be in remote parts of the building – this will satisfy the requirement to provide a means of giving people warning in case of fire.

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Question

Consider now a 60 bed residential care home which provides nursing care to frail and elderly residents, many of whom are bedridden. The building is laid out over 3 floors and occupies a footprint of 50m x 50m.

There are 30 staff employed in the premises and they are deployed across all floors of the building involved in tasks ranging from the delivery of specialist nursing care to general cleaning duties. Does this building need a fire alarm?

Answer

Categorically Yes. As in the example above, Article 13(1) of the Order says that there must be sufficient measures in place to detect fire, in this case however it is not acceptable to rely upon staff detecting a fire due to the potential for a fire to start unnoticed and develop to a point where bedridden residents would be threatened by a rapidly spreading fire and smoke layer.

trusted fire safety assessment and training partner

Therefore in these circumstances a fire alarm that includes automatic smoke detection would be an absolute necessity when considering if the requirements of Article 13(1) had been met.

Indeed for a care home a very sophisticated automatic fire alarm system
comprising of a;

  • control panel,
  • sounder devices,
  • smoke detectors,
  • heat detectors and
  • possibly fire door hold-open devices would be required.

The standard expected would be that described by
BS5839 Part 1:2013 Category L1.

This standard would see all rooms and spaces throughout the premises being provided with automatic smoke/heat detection and the provision of manual fire alarm call points at each story exit.

Where a fire risk assessment concludes that a fire alarm system is required, it is important that the correct standard of system is selected and installed by a competent person.

The choice of systems will be influenced by:

  • the usage of the premises,
  • the processes carried out within the building,
  • the physical layout of the building,
  • the numbers and type of persons who occupy the premises and
  • any other specific features in the premises which could affect the ability of persons to escape in case of fire.

Fire Alarm Systems in Commercial Type Premises

When assessing the suitability and scale of provision of fire detection and fire warning equipment within the majority of premises used for;

  • commercial,
  • healthcare,
  • educational,
  • public access,
  • industrial and
  • other similar uses,

due reference should be made to BS 5839, Part 1: 2013,
which is the most up to date standard relating to commercial standard fire alarm systems.

For clarity, BS 5839, Part 1:2013 divides fire alarm systems into 3 principal categories which are further divided into distinct descriptions of

  • (L) Life
  • (P) Property
  • (M) Manual

type systems.

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These descriptions are listed below:

Category P Fire Alarm Systems

BS 5839 Category P Fire Alarm Systems are designed specifically for protection of property only.

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Category P systems are split into 2 classifications; P1 and P2.

• BS 5839 Category P1 System Explanation

The main objective of a Category P1 fire alarm system is to provide the earliest possible warning of a fire to minimise the time between ignition and the arrival of the Fire Service.

• BS 5839 Category P2 System Explanation

The difference between a P1 and a P2 system is that a P1 system is designed to protect the whole building, whereas a P2 system is installed in defined parts of the building only.

These defined parts of the building may be areas with an extraordinarily high fire risk or hazard.

Category L Fire Alarm Systems

The main objective of a BS 5839 Category L Fire Alarm System is life protection.

These systems are split into 5 classifications;

L1, L2, L3, L4 and L5.

L1systems

• BS 5839 Category L1 System Explanation

A BS 5839 Category L1 system includes automatic fire detection in all rooms, on all escape routes and in all voids over 600mm in height.

Sounders should be positioned so as to achieve a minimum of 65dB(A) throughout the building and 75dB(A) at the bedhead where there is a sleeping risk.

In areas of high ambient noise sound levels, the fire alarm sound levels should be 5dB(A) above the normal background noise level, although it should not exceed 120dB(A).

• BS 5839 Category L2 System Explanation

A BS 5839 Category L2 system should include automatic fire detection on all escape routes and rooms leading onto escape routes.

An L2 system can also include additional areas deemed as a high risk and which are not included in the escape routes and adjoining rooms, for example – boiler houses.

The sounder requirements in the building should be according to the description in the BS 5839 Category L1 as above.

• BS 5839 Category L3 System Explanation

A BS 5839 Category L3 system is very similar to a Category L2 system in that automatic fire detection should be positioned on escape routes and adjoining rooms,

although it does not have to include additional areas which are deemed to have a high fire risk.

The sounder requirements in the building should be according to the description in the BS 5839 Category L1 as above.

• BS 5839 Category L4 System Explanation

A BS 5839 Category L4 system includes automatic fire detection on escape routes only, and not in the adjoining rooms as per the L2 and L3 classifications.

The sounder requirements in the building should be according to the description in the BS 5839 Category L1 description as above.

• BS 5839 Category L5 System Explanation

A BS 5839 Category L5 system is designed for buildings that have a particular fire risk identified within a Fire Risk Assessment and which warrants some special attention.

These systems do not have to include manual call points and may consist of detection-only solutions to highlighted problems.

However, where manual call points are also required, for example if there is an area of high fire risk which is considered worthy of having some automatic detection but a manual system is also needed, then this will be indicated as L5/M.

The sounder requirements in the building should be according to the description in the BS 5839 Category L1 description as above.

Category M Fire Alarm Systems

A Category M fire alarm system

consists of manually operated call points positioned at strategic locations within a premises.

categoryM

Distribution of Manual Call Points should be that
no one needs to travel more than 45m
(Rule 20.2e the 45m rule is reduced to 25m where a significant proportion of the occupants have limited mobility or 16m in areas of high flammable liquids or gas).

M only type systems are usually only found in buildings such as schools and older office blocks which have had a fire alarm system installed prior to the requirement for automatic fire alarms was made and often were installed to the requirements of CP1019 which was superseded by BS 5839 in 1980.

This type of system is only recommended where a site is fully manned at all times, preferably with clear sight of all areas being available

Fire Alarm Systems in Residential Premises

When carrying out an assessment of the suitability and scale of provision of fire detection and fire warning equipment within the majority of premises used for residential accommodation,

and which comprises of flats (purpose built and converted), maisonettes, houses in multiple occupation and other similar non-commercial sleeping accommodation,

due reference should be made to BS 5839, Part 6:2004

(unless the risk profile of the premises requires the provision of higher grade systems
whereby due reference should then be made to BS 5839, Part 1: 2013.

For example, multi-storey blocks of flats or sheltered housing schemes).

Part 6 systems are subdivided into 3 categories,

LD1 –
a system installed throughout the dwelling,
incorporating detectors in all circulation spaces that form part of the escape routes from the dwelling,
and in all rooms and areas in which a fire may start,
other than toilets, bathrooms and shower rooms.

• LD2
a system incorporating detectors in all circulation spaces that form part of the escape routes from the dwelling,
and in all rooms or areas that present a high risk of fire.

• LD3 –
a system incorporating detectors in all circulation spaces that form part of the escape routes from the dwelling.

Part 6 systems are then subdivided into various Grades

it is important to note that Part 6 systems must be specified by referral to both Category AND Grade.

• Grade F –
a system of one or more battery powered smoke alarms
(and heat detectors if required).

• Grade E –
a system of interlinked mains powered smoke alarms
(and heat detectors if required)
with NO stand-by supply.

The interlink can be hardwired or radio-interlinked.

• Grade D –
a system incorporating one or more interlinked mains powered smoke alarms
(and heat detectors if required),
each with an integral stand-by supply.

The interlink may be hardwired or radio-interlinked.

• Grade C –
a system consisting of smoke detectors and sounders
(which may be smoke alarms)
connected to a common power supply,
comprising normal mains and stand-by supply,
with central control equipment.

• Grade B –
a fire detection and alarm system comprising fire detectors
(other than smoke alarms),
fire alarm sounders and control and
indicating equipment to either BS EN 54-2
(and power supply to BS EN 54-4),
or to Annexe C of BS 5839: Part 6.

• Grade A –
a fire detection system incorporating control and
indicating equipment to BS EN 54-2,
and power supply to BS EN 54-4,
installed to BS 5839: Part 1
with some minor exceptions.

Fire Alarm Systems : General Issues

In some modern purpose-built blocks of residential flats,
smoke detection systems may need to be installed for the purpose of actuating Automatic Opening Vents (AOV)
which fullfil the role of keeping means of escape staircases free from smoke.

In these instances the system would not be a fire alarm system per se,
but would merely be the trigger mechanism for actuating the vents.

Where older type fire alarm systems,
which are powered directly from mains supply (240v systems) are installed within premises,

in line with the recommendations contained within the
Health & Safety (Safety Signs and Signals) Regulations 1996,
these types of fire alarm systems would not now be deemed as fit for purpose.

These older systems should be replaced with more modern fire detection and warning systems which incorporate integral battery back-up facilities.

This is due to the
Health & Safety (Safety Signs and Signals) Regulations 1996
requiring alternative power supplies to be provided for any
electrical signal which is relied upon for safety in any premises.

 

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