Advanced Quick Zone XL, Installation, Commissioning & Operating Manual

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2 DESIGN CONSIDERATIONS
2.1 SYSTEM DESIGN & PLANNING
What is a detection zone?
In order to direct those responding to a fire alarm signal, particularly the fire service, to the area of a fire, all
buildings, other than very small buildings, need to be divided into detection zones. Detection zones need to be
small enough for a fire to be located quickly.
• If the total floor area of the building is greater than 300m
2
, each zone should be restricted to a single storey
• If the total floor area of the building is less than 300m
2
a zone may cover more than a single storey
• For voids above or below the floor area of a room, these may be included within the same zone of the room,
provided that the void and the room constitute a single fire compartment
• The floor area of a single zone should not exceed 2000m
2
.
Detectors
• A person searching a zone for a fire in a non- addressable fire system should not have to travel more than
60m to identify the source of a fire
• The sensing element of a smoke detection device should not be less than 25mm and not more than 600mm
below ceiling
• The sensing element of a heat detector should not be less than 25mm and not more than 150mm below ceiling
• When mounted on a flat ceiling, smoke detection devices have an individual coverage of 7.5m radius.
However these radii must overlap to ensure there a
re no ‘blind spots’. Therefore individual coverage can be
represented by a square measuring 10.6m x 10.6m giving an actual coverage of 112m
2
per device
• When mounted on a flat ceiling, heat detection devices have an individual coverage of 5.3m radius. However
these radii must overlap to ensure there are no ‘blind spots’. Therefore individual coverage can be represented
by a square measuring 7.5m x 7.5m giving an actual coverage of 56.3m
2
per device.
Call Points
• A person should not have to travel more than 45m along an escape route to reach a Manual Call Point (25m if
disabled person to operate, or rapid fire development is likely). Manual Call Points should be sited at all stair
wells and exits from the building.
• The frangible element of the manual call point should be positioned 1.4m (+/- 200mm) from the floor level.
(Unless a wheelchair user is likely to be the first person to raise the alarm).
Sounders
• Sounder device cabling should be arranged so that in the event of a fault, at least one sounder will remain
operational during a fire condition.
• The minimum sound level should be 65dB(A) or 5dB(A) above a background noise which is louder than
60dB(A) (if lasting more than 30 seconds) and at a frequency of between 500Hz and 1000Hz.
The maximum sound level should not be greater than 120dB(A) at any normally accessible point. This may be
reduced to 60dB(A) in stairways, enclosures up to 60m
2
and specific points of limited extent.
• For areas where people are sleeping, sounder devices should produce a minimum 75dB(A) at the bed-head
with all doors shut. In buildings providing sleeping accommodation for a significant number of people, all
bedrooms should have both audible and visual alarms.
Beacons
• Visual alarms such as beacons should always be mounted at a minimum height of 2.1m from floor level.
This guide is intended as an aid to
designers and installers of fire
detection systems. It is NOT to be
used as a substitute to BS5839
which should be read in full.
A few handy tips
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