Document ID: chunk:federal_register_of_legislation:F2018L01513:body:0:p8
Version: federal_register_of_legislation:F2018L01513
Segment Type: other
Provision Reference: 
Character Range: 23876–26991

1 according to IEC 60942:2003. Without any further adjustment the difference between the readings of two consecutive checks shall be less than or equal to 0.5 dB.
               If this value is exceeded, the results of the measurements obtained after the previous satisfactory check shall be discarded.
              6.2.1.3.  Compliance with requirements
               Compliance of the sound calibrator with the requirements of IEC 60942:2003 and compliance of the instrumentation system with the requirements of IEC 61672-3:20133 shall be confirmed by the existence of a valid certificate of compliance.
              6.2.2.  Instrumentation for other measurements
               The voltage shall be measured with instrumentation having an accuracy of ±0.05 V or better.
 The resistance shall be measured with instrumentation having an accuracy of ±0.01 Ω or better.
 The distance shall be measured with instrumentation having an accuracy of ±5 mm or better.
               The time shall be measured with instrumentation having an accuracy of ±0.02 s or better.
               The meteorological instrumentation used to monitor the environmental conditions during the test shall include the following devices, which meet at least the following accuracy:
                  (a) Temperature measuring device, ±1° C;
                  (b)  Wind speed-measuring device, ±1.0 m/s;
                  (c)  Barometric pressure measuring device, ±5 hPa;
                  (d)   A relative humidity measuring device, ±5 per cent.
6.3. Measurement of the sound characteristics.

              6.3.1. The audible warning device, audible warning system, multiple audible warning system should, preferably, be tested in an anechoic chamber. Alternatively, it may be tested in a semi-anechoic chamber or in an open space.[4] In these cases, precautions shall be taken to avoid reflections from the ground within the measuring area (for instance by erecting a set of absorbing screens). The wind speed shall be not more than 5 m/s. The ambient noise level shall be at least 10 dB lower than the sound pressure level to be measured.

If the test facility shall be qualified as an anechoic environment it shall meet requirements of Annex 3.
              6.3.2. The audible warning device, audible warning system, multiple audible warning system to be tested and the microphone shall be placed at the same height. This height shall be 1.20 ± 0.05 m.

In alternative, the audible warning device, audible warning system, multiple audible warning system to be tested and the microphone may be placed in another traverse line which complies with Annex 3 specification for anechoic environment.
               The microphone shall be so placed that its diaphragm is at a distance
              of 2.00 ± 0.05 m from the plane of the sound outlet of the audible warning device, audible warning system, multiple audible warning system. The microphone must be positioned facing the front surface emitting sound of the audible warning device, audible warning system, multiple audible warning system in the direction in which the maximum