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Planning
4
Fire detection
4.2.2 Parameter sets: Sensor mode 0 'Neural fire detector'
4.2.2.1 Description
48 | 94
Building Technologies
Fire Safety
Deceptive phenomena
Deceptive phenomena can deceive a fire detector and bring about a false alarm.
The deceptive phenomena differ depending on the fire detector. Deceptive
phenomena include
Steam
Cigarette smoke
Dust
Dry ice in discotheques
Exhaust fumes
Aerosols produced when welding
Sources of heat such as radiant heaters or hot engines
In a small hotel room with a rather low ceiling where vapor from the bathroom may
penetrate the room, or in operating facilities where a lot of dust is generated, many
deceptive phenomena must be taken into consideration. In a clean room where
electronic modules are fabricated the risk of deceptive phenomena is rather low.
Risk of fire
In production facilities where highly combustible materials such as flammable
liquids, cotton, paper etc. are processed and where electrical machines are
operated, the fire risk is very high. Minor overheating or sparks may cause a fire. In
a storehouse where steel is stored and where no electrical installation is provided
with the exception of lighting, the fire risk is very low.
Critical fire size
When a waste paper basket in a metal-processing facility catches fire, the
consequential damage is usually rather low. Here we are talking about a critical,
medium fire size that can still be tolerated. The situation is completely different in
pharmaceutical production facilities where even the lowest smoke concentration
may impair the process and where combustible materials are processed. Even the
smallest fire must be detected immediately. In this case, we are talking about a
small admissible critical fire size.
(Parameter set numbers in brackets)
High Suppression (8)
To cover applications with permanent, optical deceptive phenomena (dry ice in
discotheques, welding), this parameter set only reacts when a temperature rise of
approx. 8 K is detected in addition to the optical signal. Due to the combination of
optical and thermal signals, it is better suited than a pure heat detector. This
parameter set is also suited for applications that can otherwise only be covered
with special detectors.
Suppression (5)
Thanks to its very robust behavior, the 'Suppression (5)' parameter set is
particularly suitable for rooms where deceptive phenomena such as vapor, very
dense cigarette smoke or exhaust fumes can be expected. It reacts in a very
robust way to the deceptive phenomenon vapor.
A6V10209291_h_en_--
2016-03-03
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