Smoke Alarm User Manual

8
Note: This document is based on the recommendations of BS5839 Part 1: 2002. It is intended only as a guide to the application of fire detection systems.
Reference must be made to relevant national and local standards.
2. DETECTOR APPLICATION GUIDE
2.1. FIRE SYSTEM CATEGORIES.
Before a fire protection system can be designed, it is necessary to define the main objectives of the system. This is normally
determined by a fire risk assessment, and should be provided as part of the fire system specification. BS5839 Part 1: 2002
defines three basic categories of fire detection system.
2.1.1. Category M Systems
Category M systems rely on human intervention, and use only
manually operated fire detection such as break glass call
points. A category M system should only be employed if no
one will be sleeping in the building, and if a fire is likely to be
detected by people before any escape routes are affected.
Any alarm signals given in a category M system must be
sufficient to ensure that every person within the alarm area is
warned of a fire condition.
2.1.2. Category L Systems
Category L systems are automatic fire detection systems
intended to protect life. The category is further subdivided as
follows:
Category L5: In a category L5 system certain areas within
a building, defined by the fire system specification, are
protected by automatic fire detection in order to reduce the
risk to life. This category of system may also include manual
fire protection.
Category L4: Designed to offer protection to the escape
routes from a building. The system should comprise Category
M plus smoke detectors in corridors and stairways
Category L3: Intended to offer early enough notification of a
fire to allow evacuation before escape routes become smoke
logged. Protection should be as for category L4 with the
addition of smoke or heat detectors in rooms opening onto
escape routes.
d
o
w
n
Canteen
Kitchen
Pantry
Paper
Store
Office
Office
d
o
w
n
Pantry
Kitchen
Canteen
Office
Office
Paper
Store
do
wn
Canteen
Kitchen
Pantry
Paper
Stor
e
Offic
e
Offic
e
d
o
w
n
Canteen
Kitchen
Pantry
Paper
Store
Office
Office
Example L5 System: L4 protection plus areas of high risk
Application Guide