EN 54-22 Compliant Linear Heat Detectors: Following a transitional period of four years, all linear heat detectors installed from 1 May 2019 onwards must be EN 54-22 compliant. The European product standard now in force primarily describes test requirements and performance features, such as response behaviour. Linear heat detectors have until now been tested and certified according to the EN 54-5 European product standard for point-type heat detectors.
The European Committee for Standardisation set up a working group, one of whose tasks was to specify a product standard specifically for linear heat detectors. A distinction is made between two types of linear heat detectors: resettable and non-resettable. The latter cannot be reset after a fire and must therefore be replaced. Non-resettable linear heat detectors are described in a separate standard (EN 54-28), while resettable linear heat detectors come under EN 54-22.
Guaranteed Procurement Security
The SecuriSens ADW 535 from Securiton is one of the few resettable linear heat detectors on the market to comply fully with the new EN 54-22 standard. This renewed VdS device approval guarantees not only security of investment and procurement for installers of the fire detector, but also conformity with standards and directives.
Linear heat detectors comprise an evaluation unit linked to a sensor element consisting of a sensing tube made of copper or stainless steel or a hose-like sensing tube made of Teflon. The functional principle has proved its reliability for many decades: a fully electronic pressure sensor continuously detects the pressure in the sensing tube, which is constantly monitored by the evaluation electronics and compared with the alarm criteria. A rise in temperature leads to increased pressure in the sensing tube, which is detected by the electronic sensor of the SecuriSens ADW 535.
The fire detector instantly triggers an alarm if the rise exceeds the predefined limit. A distinction is drawn between two alarm criteria: under the ‘maximum temperature response behaviour’ criterion, the detector triggers an alarm if a maximum alarm threshold or specific temperature is reached. Under the ‘differential behaviour’ criterion, the detector triggers an alarm if a temperature increase occurs within a certain time. Experience shows that most fires are identified using the differential behaviour criterion.
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