British standard BS5839 covers the usage of Fire Alarms:

• Part 1 covers Alarms in Commercial and Public Buildings.

• Part 6 covers Alarms in Houses and smaller Buildings of Multiple Occupancy.

Each Part is then further sub-divided to suit the use of the building and the Fire Risk and whether protection is required for Life or Property.

BS 5839: Part 1

BS 5839-1 is the code of practice for designing, installing, commissioning, and maintaining fire detection and alarm systems in non-domestic buildings, it contains recommendations for the locations of fire alarm system components based on the objective the system should fulfil - known as Categories. These Categories are L and M for systems designed to protect life and Category P for those intended to protect property. It is perfectly acceptable, and very common, for a fire alarm system installed in a building to incorporate a mixture of Categories.

Part 1 Life Protection Categories:

• Category M Manual
    A manual system, incorporating no automatic fire detectors.

• Category L Life Protection
    This classification provides for the protection of life, that is the safety of the occupants. It caters for the detection of a fire, initiates an alarm of fire, and provides sufficient time for the occupants to escape from the building. This is then further divided as follows:

• Category L5

The protected area and/or the location of detectors is designed to satisfy a specific fire safety objective. This may be defined in a fire engineering solution or from a fire risk assessment.

• Category L4

Covers those parts of the escape routes comprising circulation areas and circulation spaces, such as corridors and airways.

• Category L3

Covers escape routes and rooms opening on to escape routes (detectors may be situated adjacent to the door onto the escape route).

• Category L2

Covers the areas protected by Category 3 system plus other areas where it is considered that there is a high fire hazard and/or fire risk.

• Category L1

Total coverage throughout the building.

Part 1 Property Protection Categories:

• Category P Property Protection
    This classification provides for the protection of property and its contents. It caters for the automatic detection of a fire, initiates an alarm of fire, and results in summoning of the fire brigade (which may be by a means of automatic transmission of fire signals to an Alarm Receiving Centre).

• Category P2

Covers areas of high fire hazard or high risk to property or business continuity from fire.

• Category P1

Total coverage throughout the building.

BS 5839: Part 6

BS 5839-6 covers fire alarm systems starting from a simple self-contained battery smoke alarm right through to major systems with central panel(s) in accordance to BS 5839-pt1.

It is for the following domestic building types:

• Bungalows
• Multi-storey houses
• Individual flats
• Individual maisonettes
• Mobile homes
• Individual sheltered accommodation as well as their common parts
• Houses in multiple occupation (HMOs)
• Certain NHS housing in the community
• Mansions
• Shared houses
• Houses divided into several self-contained single-family dwelling units

The Grade System

Relates to system engineering, not level of protection.

BS 5839: Pt.6 grades fire detection systems from Grade F up to Grade A. Generally speaking, the greater the fire risk and the more demanding the application, the more comprehensive the system needs to be.

• Grade F - System of one or more interlinked battery powered smoke alarms (and heat alarms if required). F1 tamper-proof battery / F2 user replaceable battery.
• Grade D - System incorporating one or more interlinked mains powered smoke alarms (and heat alarms if required), each with an integral stand-by supply. The interlink can be hardwired or radio-interlinked. D1 tamper-proof battery / D2 user replaceable battery.
• Grade C - System consisting of fire detectors and alarm sounders (which may be smoke alarms) connected to a common power supply, comprising normal mains and stand-by supply, with central control equipment
• Grade 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: Pt.1 with some very minor exceptions

Levels of Protection - Categories of System

This relates to the level of protection afforded by the system.

Within the A - F grades defined earlier, the standard identifies three different categories of protection:

• 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 fire might 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 premises, and in all rooms or areas that present a high risk of fire to occupants
• LD3 - A system incorporating detectors in all circulation spaces that form part of the escape routes from the premises

It is noted that an LD3 type system is intended to protect escape routes for those not directly involved in the fire and may not save the life of anyone in the immediate vicinity of the fire.

Only by quoting Grade and Category can a meaningful and effective alarm system be specified, e.g. Grade D, Category LD2.

The Security Network

We can supply, install, maintain and take over the maintenance of all of the above types of Fire Alarm Systems. We are a NSI Gold BAFE Installer and can provide certification that installations conform to the relevant Category / Grade.

Call us on 0800 040 7597 for further information.

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