Differentiation of detectors according to their mounting position
The distinction between ceiling detectors and lintel detectors mentioned hereunder is only due to their installation position. They are not different detectors.
The position in which the detectors are installed (on the ceiling or directly on the lintel) depends, among other aspects, on the distance between the top edge of the door and the ceiling, as well as the type of fire protection closure.
- Ceiling detectors should be installed directly below the ceiling undersurface above the clear door opening – at least one on each side.
- The horizontal distance of the detectors from the wall should be, at least, 0.5 m and 2.5 m at most.
- If the distance between the ceiling and the clear opening is more than 5 m, detectors should be installed on cantilever arms with a length of 0.5 m, and at least 3.5 m above the opening.
Special regulations for ceiling detectors on suspended ceilings
If suspended ceilings or false ceilings are installed, the following points must be clarified:
- Is the suspended ceiling permeable to smoke?
- Is the suspended ceiling impermeable to smoke?
- Where does the highest smoke concentration arise first ?
- If the bottom part of the ceiling on one or both sides of the opening is more than 1.0 m above the top edge of the clear opening, at least one additional lintel detector must be fitted directly to the wall above the clear door opening and max. 0.1 m above the bottom edge of the lintel. For an easy installation, DICTATOR supplies a mounting bracket (part no. 040570).
- If the clear opening is not wider than 3.0 m and is closed by a hinged door, it is enough to install only one lintel detector instead of two ceiling detectors if the bottom part of the ceiling is no more than 1.0 m above the upper edge of the opening to be protected on both sides.
Special regulation for hinged doors
Illustration to point 2
In double hinged doors, both lintel and ceiling detectors must be installed above the active leaf.
Detection range / coverage radius of fire detectors
It is assumed that each fire detector is capable of detecting fire or smoke in an area of 2 m in each direction.
If the width of the door opening is greater than 4 m, additional detectors or detector pairs are required:
- Opening width > 4 metres: double number of detectors
- Opening width > 8 metres: triple number of detectors
- Opening width > 12 metres: four times the number of detectors
Decision diagram for determining the required number of fire detectors
With the help of the decision diagram below, it can be easily determined how many fire detectors are needed and whether they should be lintel or ceiling detector or both!
Additional detectors are required according to EN 14637 for opening widths greater than 4.0 metres!
- Opening width more than 4 metres -> double number of ceiling and lintel detectors are required
- Opening width more than 8 metres -> triple number of ceiling and lintel detectors are required
- Opening width more than 12 metres -> four times the number of ceiling and lintel detectors are required
Smoke or heat detector?
Smoke detectors should be used whenever possible.
If smoke or dust occurs during rutine working or manufacturing processes and there is a danger that smoke detectors may trigger false alarms, heat detectors should be used.
Heat detectors should not be used on smoke closures, as smoke is not detected by them and thus the smoke protection function cannot be fulfilled.