BS EN 17285:2020 pdf free.Railway applications一Acoustics一Measuring of door audible warnings.
BS EN 17285 Each component of the instrumentation system shall meet the requirements for a class 1 instrument specified in EN 61672-1.The sound calibrator shall meet the requirements of class 1 according to EN IEC 60942.Microphones with free-field characteristics shall be used. A suitable microphone windscreen may be used.Where one-third octave frequency band analysis is required, the filters shall meet the requirements of class 1, according to EN 61260.The compliance of the calibrator with the requirements of EN IEC 60942 shall be verified at least once a year. The compliance of the instrumentation system with the requirements of EN 61672-1 and EN 61672-2 shall be verified at least every 2 years. The date of the last verification of the compliance with the relevant European Standards shall be recorded.Before and after each series of measurements a sound calibrator meeting the requirements of class 1 according to EN IEC 60942 shall be applied to the microphone(s) for verifying the calibration of the entire measuring system at one or more frequencies over the frequency range of interest. If the difference between the two calibrations is more than 0,5 dB all the measurement results in between shall be rejected.The door opening of the vehicle shall be at least 5 m away from reflecting walls or roof of any building. There are no requirements on the external ground conditions or ground height. Care shall be taken to ensure that noise from other sources, e.g. other vehicles or industrial plants and due to external wind, does not influence the measurements significantly. For fixed-level sounders, the background noise level LpAeq,T measured over T= 20 s of each measurement position shall be at least 10 dB below the level of the warning signal (LpAF, LpAFmax and, possibly,
LpAeq,T, see 6.4). For adaptive-level sounders, the effective background noise is controlled under the measurement procedure itself – see Annex B.BS EN 17285 pdf downlaod.