BS EN 54-7-2001 pdf download.Fire detection and fire alarm systems Part 7: Smoke detectors — Point detectors using scattered light, transmitted light or ionization.
The specimens orientation relative to the direction of air flow Is arbitrary, but it shall be the same for all six measurements.
The maximum response threshold value shall be designated or nj, the minimum value shall be designated 3,, or m.
5.2.3 Requirements
The ratio of the response threshold values v,: v, or mmai : mmi,, shall not be greater than 1.6.
The tower response threshold value v,, shall be not less than 0.2, or m shall not be less than 0,05 dB m1.
5.3 Directional dependence
5.3.1 Object
To confirm that the sensitivity of the detector is not unduly dependent on the direction of airflow around the
detector.
5.3.2 Test procedure
The response threshold value of the specimen to be tested shall be measured eight times as described in 5.1.5. the specimen being rotated 450 about Its vertical axis between each measurement, so that the measurements are taken for eight different orientations relative to the direction of air flow.
The maximum response threshold value shall be designated or n:,,… the minimum value shall be designated i or m,.
The orientations for which the maximum and minimum response threshold values were measured shall be noted.
In the following tests the orientation for which the maximum response threshold was measured is referred to as the least sensitive orientation, and the onentation for which the minimum response threshold was measured is referred to as the most sensitive orientation.
5.3.3 Requirements
The ratio of the response threshold values : Ymin or 11max rnmin shall not be greater than 1.6.
The lower response threshold value v, shall not be less than 0,2, or ni,, shall not be less than 0,05 dB m.
5.4.1 Object
To show that the sensitivity of the detector does not vary unduly from specimen to specimen and to establish response threshold value data for comparison with the response threshold values measured after the environmental tests.
5.4.2 Test procedure
The response threshold value of each of the test specimens shall be measured as described in 5.1.5.
The mean of these response threshold values shall be calculated and shall be designated • or i.
The maximum response threshold value shall be designated v or in the minimum value shall be designated .ViThn or m,,.
5.4.3 Requirements
The ratio of the response threshold values v: 1 or rn,: ii shall not be greater than 133. and the ratio of the response threshold values • or ñï : rn shall not be greater than 15.
The lower response threshold value i, shall not be less than 0.2, rn shall not be less than 0,05 dB m1
5.5 VarIation In supply parameters
5.5.1 Object
To show that, within the specified range(s) of the supply parameters (e.g. voltage), the sensitivity of the
detector Is not unduly dependent on these parameters,
5.5.2 Test procedure
The response threshold 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 threshold value shall be designated ,v or n, and the minimum value shall be designated v or mmin.
NOTE: For conventional detectors the supply parameter is the dc voltage applied to the detector. For other types of detector (e.g. analogue addressable) signal levels and timing may need to be considered. If necessary. the manufacturer may be requested to provide suitable supply equipment to allow the supply parameters to be changed as required.
5.6 Air movement
5.6.1 Object
To show that the sensitivity of the detector is not unduly affected by the rate of the air flow, and that it is not
unduly prone to false alarms in draughts or in short gusts.
5.62 Test Procedure
The response threshold value of the specimen to be tested shall be measured as described in 5.1.5 in the most and least sensitive orientations, and shall be appropriately designated ‘(O2* and )O,2n or rn(O•2 and m1o,.
These measurements shall then be repeated but with an air velocity, in the proximity of the detector, of
(1 ± 0,2) m s1. The response thresho’d values in these tests shall be designated Y(1o and ,1,O)min or
and 111(1oin.
Additionally, for detectors using ionization, the specimen to be tested shall be subjected. in its most sensitive orientation, to an aerosol-free air flow at a velocity of (5 ± 0,5) m s’ for a period of not less than 5 mm and not more that 7 mm, and then at least 10 mm later to a gust at a velocity of (10 ± 1) m s’ for a period of not less than 2 s and not more than 4 s. The specimen shall be monitored during the exposure to aerosol-free air to detect any alarm or fault signals.
NOTE: These exposures can be generated by plunging the specimen to be tested into an airflow with the appropriate velocity for the required time
5.6.3 RequIrements
For detectors using ionization the foflowing shall apply:BS EN 54-7-2001 pdf download.