BS5839: Part 1: 2002

The principle UK standard for fire alarm system design, installation and maintenance.  This is the reference level referred to in the Regulatory Reform (Fire Safety) Order 2005 that affects all non-domestic premises.

Systems are required to meet this standard as a minimum.

Sound Pressure Requirements

Areas over 60 square metres:    65dBA

Corridors:                                 65dBA

Stairwells, small rooms:            60dBA (limited extent)

In rooms for sleeping:                75dBA (at the bed head)

High noise lasting over 30 seconds: 5dBA over noise

Visual indicators may be suitable

Maximum Sound Level: 120dBA not to be exceeded

Life Protection Categories

These systems are designed to provide a warning to occupants to protect against the threat of injury or death from fire.  For this reason, regardless of the Category selected, alarm devices (bells or sounders) are provided throughout.

M     Manual Call Points (MCP) where required by
        BS5839

L4    As M but with detectors to all escape routes

L3    As L4 plus detectors to all rooms opening
       onto escape routes

L2    As L3 but with detection to specified rooms or areas

L1    L1 is to protect all occupants so extensive
       detectors used

L5    A system designed to the Risk Assessment for which the Risk Assessor takes full legal responsibility.These should only be undertaken with specialist knowledge and insurance

Property Protection Categories

These systems are designed to protect property.  Sounder locations and sound levels will not necessarily need to meet the standard for Life systems except where the /M suffix is used to indicate that Manual Call Points are required.

P1                Automatic detectors throughout

P1/M            As P1 plus Manual Call Points

P2                Automatic detectors to specified areas

P2/M            As P2 plus Manual Call Points