AS ISO 7240.24:2018 pdf free.Fire detection and alarm systems Part 24: Fire alarm loudspeakers.
5.1.2 Operating conditions for tests
5.1.2.1 Unless otherwise stated in a test procedure, the test specimen shall be
a) set to its highest power setting,
b) preconditioned in accordance with Annex A, and
c) mounted in the acoustical environment as described in Annex A and as specified by the manufacturer [see Clause 8 j)].
5.1.2.2 If different settings, except power settings, are available on the loudspeaker, such as tone control or adjustable parts (excluding external mounting bracket), the manufacturer shall specify the configuration(s) to be tested.
5.1.2.3 The details of the settings shall be given in the test report (see Clause 6).
5.1.3 Mounting arrangements
5.1.3.1 For environmental conditioning tests, unless otherwise specified, the specimen shall be mounted by its normal means of attachment in accordance with the manufacturer’s instructions.
If these instructions describe more than one method of mounting, the method considered as the most unfavourable shall be chosen for each test.
5.1.3.2 For some loudspeakers, due to their size, it might not be practical to conduct all of the environmental tests.
In such cases, testing may be carried out on a smaller representative specimen, where this is deemed to produce a valid result for a given test.
5.1.4 Tolerances
5.1.4.1 The tolerances for the environmental test parameters shall be given in the basic reference standards for the test (e.g. the relevant part of IEC 60068).
5.1.4.2 If a specific tolerance or deviation limit is not specified in a requirement or test procedure, then a deviation limit of ±5 % shall be applied.
5.1.5 Frequency response measurement and sensitivity calculation
5.1.5.1 Measuring arrangement
Measurements shall be made in accordance with Annex A.
5.2 Reproducibility
5.2.1 Object of the test
To show that the acoustical performance of the loudspeaker does not vary unduly from specimen to specimen and to establish performance data for comparison with the performance data measured during and/or after the environmental tests specified in this part of Iso 7240.
5.2.2 Test procedure
5.2.2.1 Measure and plot the frequency response of all the specimens as described in 5.1.5 or, if applicable, 5.1.6.
5.2.2.2 Calculate the sensitivity, S, as described in 5.1.5 or, if applicable, 5.1.6 for each specimen.
5.2.3 Requirements
5.2.3.1 The frequency response curve fits within the limits shown in 4.2;
5.2.3.2 The sound pressure levels in the 1/3 octave bands with centre frequencies from 500 Hz to
4 kHz are within ±4 dB of the manufacturer’s specified curve.AS ISO 7240.24 pdf download.