BS ISO 7240-12:2013 pdf free

BS ISO 7240-12:2013 pdf free.Fire detection and alarm systems一Line type smoke detectors using a transmitted optical beam
If a test method requires a specimen to be operational, then connect the specimen to suitable supply and monitoring equipment having the characteristics required by the manufacturer’s data. Unless otherwise specified in the test method, set the supply parameters applied to the specimen within the manufacturer’s specified range(s) and maintain them substantially constant throughout the tests. The value chosen for each parameter shall normally be the nominal value, or the mean of the specified range. If a test procedure requires a specimen to be monitored to detect any alarm or fault signals, then connect the specimen to any necessary ancillary devices (e.g. through wiring to an end-of-line device for non-addressable detectors) to allow a fault signal to be recognized.
Adjust the sensitivity to the minimum recommended for the separation applied, as indicated in manufacturer’s data.
Any adjustment for path length or alignment shall be carried out in accordance with the manufacturer’s instructions.
If the size of the test room does not allow the detector to be tested at its maximum specified separation, a method agreed with the manufacturer (e.g. use of attenuators) should be used to simulate the specified separation.
Mount the two specimens (Nos. 6 and 7) on the fire test room ceiling in the designated area (see Annex C) in accordance with the manufacturer’s instructions.
Connect each specimen to its supply and monitoring equipment, as specified in 5.1.3, and allow it to stabilize in its quiescent condition before the start of each test fire.
Detectors which dynamically modifty their sensitivity in response to varying ambient conditions could 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 detectors at the start of each test is representative of their normal quiescent state.
Apply impacts to each point on each component in turn which is deemed to be susceptible to mechanical damage that would impair the correct operation of the detector, up to a maximum of 20 points on each component (e.g. lenses, windows and devices used for adjusting alignment may be deemed susceptible to damage). No two points at which the impacts are applied shall be less than 20 mm apart.
Take care to ensure that the results from one series of three blows do not influence subsequent series. In case of doubt with regard to the influence of preceding blows, disregard the defect and apply a further three blows to the same position on a new specimen.BS ISO 7240-12 pdf free.