BS/EN 54-7-2018 pdf download.Fire detection and fire alarm systems Part 7: Smoke detectors – Point smoke detectors that operate using scattered light, transmitted light or ionization.
5.4.2 Dazzling
5.4.2.1 Object
To show the sensitivity 01 the point smoke detector is not unauiy iniluenced by the close proximity oi artificial light sources. This test is only applied to point smoke detectors using scattered light or transmitted light as point smoke detectors using ionization are considered unlikely to be influenced.
5.4.2.2 Test procedure
The dazzling apparatus, described in Annex D is installed in the smoke tunnel described in Annex A, shall be used for the closed type point smoke detectors. The dazzling apparatus, described in Annex D shall be modified by covering one side by light absorbing material as in Annex 0 for the open type point smoke detector. The specimen is installed in the dazzling apparatus in the least sensitive orientation and connected to its supply and monitoring equipment. The following test procedure is then applied:
a) The response value is measured as described in 5.1.5.
b) The four lamps are switched simultaneously ON for 10 s and then OFF for 10 s, 10 times.
c) The four lamps are then switched ON again and after at least 1 mm the response value is measured, as described In 5.1.5, with the lamps ON.
d) The four lamps are then switched OFF.
The above procedure is then repeated for closed type point smoke detectors but with the point smoke detector rotated 900, in one direction (either direction can be chosen), from the least sensitive orientation.
For each orientation, the maximum response value shall be designated mm and the minimum response value shall be designated rnmn.
5.4.2.3 Requirements
During the periods when the lamps are being switched ON and OFF, and when the lamps are ON before the response value is measured, the specimen shall emit neither an alarm nor a fault signal.
For each orientation, the ratio of the response thresholds mm: shall not be greater than 1,6.
5.5 Tolerance to supply voltage — Variation in supply parameters
5.5.1 Object
To show that, within the specifled range(s) of the supply parameters (e.g. voltage), the sensitivity of the point smoke detector is not unduly dependent on these parameters.
5.5.2 Test procedure
The response value of the specimen shall be measured as described in 5.1.5, at the upper and lower limits of the supply parameter (e.g. voltage) range(s) specified by the manufacturer.
The maximum response value shall be designated Yrna or and the minimum value shall be designated ymin or mmn.
For conventional point smoke detectors the supply parameter is the dc voltage applied to the point smoke detector. For other types of point smoke detector (e.g. analogue addressable) signal levels and timing may need to he considered. If necessary the manufacturer may be requested to provide suitable supply equipment to allow the supply parameters to be changed as required.
5.5.3 Requirements
The ratio o[the response valuesy,:ymin or mm: mmin shall not be greater than 1,6.
The lower response valueymtn shall not be less than 0,2 or shall not be less than 0,05 dB rn-’.
5.6 Performance parameters under fire conditions
5.6.1 Fire sensitivity
5.6.1.1 Object
To show that the point smoke detector has adequate sensitivity to a broad spectrum of smoke types as required for general application in fire detection systems for buildings.
5.6.1.2 PrInciple
The specimens are mounted in a standard fire test room and are exposed to a series of test fires designed to produce smoke, representative of a wide spectrum of types of smoke and smoke flow conditions.
5.6.1.3 Test procedure
5.6.1.3.1 Fire test room
5.6.1.3.2 Test Fires
The specimens shall be subjected to the four test fires TF2 to TF5 (see NOTE and Annexes G to I). The type, quantity and arrangement of the fuel and the method of ignition are described in Annexes G to J, for each test fire, along with the end of test condition and the required profile curve limits.
In order to be a valid test fire, the development of the fire shall be such that the profile curves of m against y and m against time fall within the specified limits, up to the time when all of the specimens have generated an alarm signal or the end of test condition is reached, whichever is the earlier. If these conditions are not met then the test is invalid and shall be repeated. It is permissible, and may be necessary, to adjust the quantity, condition (e.g. moisture content) and arrangement of the fuel to obtain valid test fires.
5.6.1.3.3 Mounting of the specimens
The four specimens (Nos. 17, 18, 19 and 20) shall be mounted on the fire test room ceiling in the designated area (see Annex F). The specimens shall be mounted in accordance with the manufacturer’s instructions, such that they are in the least sensitive orientation, relative to an assumed air flow from the centre of the room to the specimen.
Each specimen shall be connected to its supply and monitoring equipment, as described in 5.1.2, and shall be allowed to stabilize in its quiescent condition before the start of each test fire.
Point smoke detectors which dynamically modify their sensitivity in response to varying ambient conditions, may require special reset procedures and/or stabilization times. The manufacturer’s guidance should be sought in such cases to ensure that the state of the point smoke detectors at the start of each test is representative of their normal quiescent state.
5.6.1.3.4 Initial conditions
Before each test fire the room shall be ventilated with clean air until it is free from smoke, and so that the conditions listed below can be obtained.
The ventilation system shall then be switched off and all doors, windows and other openings shall be closed. The air in the room shall then be allowed to stabilize, and the following conditions shall be obtained before the test is started:BS/EN 54-7-2018 pdf download.