BS EN 54-20:2006 pdf download
BS EN 54-20:2006 pdf download.Fire detection and fire alarm systems一Part 20: Aspirating smoke detectors.
b) design of the interfaces for manually and automatically generated data shall not permit invalid data to cause error in the program operation,
C) software shall be designed to avoid the occurrence of deadlock of the program flow. 5.1 2.4 Th. storag. of programs and data
The program necessary to comply with this European Standard and any pie-set data, such as manufacture?s settings, shall be held in non-volatile memory. Writing to areas of memory containing this program and data shall only be possible by the use of some special tool or code and shall not be possible during normal operation of the detector.
Site-specific data shall be held In memory which will retain data for at least two weeks without external power to the detector, unless provision Is made for the automatic renewal of such data, following loss of power, within 1 h of power being restored.
6 Tests
6.1 General
6.1.1 Atmospheric conditions for tests
Unless otherwise stated In a test procedure, the testing shall be camed out after the test specimen has been allowed to stabilize in the standard atmospheric conditions for testing as described in EN 600681 as follows:
a) temperature (15 to 35) C;
b) relative humidity . (25 to 75) %:
C) air pressure (86 to 106) kPa.
It variations In these parameters have a significant effect on a measurement, then such variations shall be kept to a minimum during a series of measurements carried out as part of one lest on one specimen.
6.1.2 Op.ratlng condItions for t.sts
if a test method requires a specimen to be operational, then the specimen shall be connected to supply and monitoflng equipment with characteflstics as required by the manufacturers data. Unless otherwise specified in the test method, the supply parameters applied to the specimen shall be set within the manufacturer’s specified range(s) and shall remain substantially constant throughout the tests, The value chosen for each parameter shall normally be the nominal value, or the mean of the specified range
Where an aspirating smoke detector has multiple sensitivity settings, the sensitivity of the DUT during all tests In Table 3 (with the exception of the fre sensitivity test in 615) shall be set at the highest sensitivity setting used duflng the fire sensitivity test(s).
NOTE It is not intended that the environmental tests are conducted at all possible sensitivity seltrigs, ordy at the hiiest used durmg the fi’e sensitivity test. This is particularly relevant where multiple dasees and/or multiple configurations are submitted.
To allow the flow monitoring function to be checked as required before, during and/or after environmental tests, the sampling device may be sinulated by a simpler sampling device (e.g. stub pipe with appropriate orifice(s)) to providing a typical airflow through the detector
Dunng the dry heat, damp heat and cold tests, a sufficient length of pipe shall be installed in the chamber to allow the temperature of the test aerosol entering the DUT to stabilize at the test temperature.
The details of the supply and monitoring equipment and the alarm cflteia used shaM be given in the test report.
6.1.3 Mounting arrangements
When necessaiy, the specimen shaM be mounted by its normal means of attachment in accordance with the rnanutacture?s instructions. If these instructions describe more than one method of mounting then the method considered to be most unfavourable shall be chosen for each test.
6.1.4 Tolerances
Unless otherwise stated, the tolerances for the environmental test parameters shall be as given in the basic reference standards for the test (I.e. the relevant Parts of EN 60068-2 as listed in Clause 2).
If a specillo tolerance or Irnilt is not specdied in a requirement or test procedure, then deviation lEnNts of± 5% shall be applied.
6.1.5 M.asur.m.nt of response threshold valu.
6.1.5.1 General
Because there are a number of different types of aspirating detectors available operating on quite different principles, which have very different ranges of sensitivity, various methods can be used to measure the response threshold value. The object of any method chosen shall be to determine a measure of the aerosol concentration, which when passing through the detector, rust causes an alarm to be raised. This can generally be achieved by introducing smoke or an aerosol mb the sampled air stream so that the detector is subjected to a slowly increasing concentration, and recording the concentration at the moment when an alarm is generated. Because the response threshold value is only used as a relative measurement, various parameters to measure the aerosol concentration may be used, providing that the chosen parameter is essentially proportional to the particie number concentration, for the particular test aerosol. For further information it is recommended to refer to Annex A.
