Fire alarm design recommendations

When designing fire alarm system, beams and other Similar Ceiling obstructions need to be considered and taken in consideration.
Fire detection should be mounted at least 500mm away from walls
or ceiling obstructions greater than 250mm deep and at least
twice the depth of obstructions less than 250mm deep. They
should also be mounted at least 1m away from any forced air
inlet. Where the obstruction is greater than 10% of the height of an
area it should be considered as a wall. Similarly a floor mounted
obstruction (such as racking) should be considered a wall if it
comes to within 300mm of the height of the detector.

Fire alarm detection - Lift Shafts
Where fire alarm detection is required in vertical shafts, such as stairwells,a detector should be mounted at the top of the shaft and within 1.5m at each level.

Manual fire detection - Selection of fire alarm manual callpoints
The selection of manual call points is somewhat simpler. Surface
or flush types are selected depending on the environment and
whether the fire alarm system is being installed into an existing building (where surface call points are generally easier to install). IP65
types should be specified where there is risk of moisture ingress,
for example in external locations. Standard fire alarm call points use a
frangible glass element which is designed to break under light
pressure triggering the call point into an alarm condition.
The glass element is covered with a thick plastic film to protect the
operator against broken glass, however plastic resettable elements
and protective flaps can be used where there is the risk of
unwanted operation or in food preparation areas. Where hinged
covers are used these should be recorded as a design variation.
Call points can be supplied with LED indicators mounted onto the
front face to simplify the location of an operated call point.