Document ID: chunk:federal_register_of_legislation:F2024L00089:reg:800:p5
Version: federal_register_of_legislation:F2024L00089
Segment Type: reg
Provision Reference: reg 800 (pt 5/16)
Character Range: 41137–44408

a sound level meter or equivalent measurement system meeting the requirements of Class 1 instruments (inclusive of the recommended windscreen, if used). These requirements are described in IEC 61672-1-2013.

              The entire measurement system shall be checked by means of a sound calibrator that fulfils the requirements of Class 1 sound calibrators in accordance with IEC 60942-2003.

              Measurements shall be carried out using the time weighting "F" of the acoustic measurement instrument and the "A" frequency weighting also described in IEC 61672-1-2013. When using a system that includes a periodic monitoring of the A-weighted sound pressure level, a reading should be made at a time interval not greater than 30 ms.

              When measurements are carried out for one-third octaves, the instrumentation shall meet all requirements of IEC 61260-1-2014, class 1.

               When measurements are carried out for frequency shift, the digital sound recording system shall have at least a 16 bit quantization. The sampling rate and the dynamic range shall be appropriate to the signal of interest.

              The instruments shall be maintained and calibrated in accordance with the instructions of the instrument manufacturer.

              1.1.2. Calibration

              At the beginning and at the end of every measurement session, the entire acoustic measurement system shall be checked by means of a sound calibrator as described in paragraph 1.1.1.. Without any further adjustment, the difference between the readings shall be less than or equal to 0,5 dB(A). If this value is exceeded, the results of the measurements obtained after the previous satisfactory check shall be discarded.

              1.1.3. Compliance with requirements

              Compliance of the sound calibrator with the requirements of IEC 60942-2003 shall be verified once a year. Compliance of the instrumentation system with the requirements of IEC 61672-3-2013 shall be verified at least every 2 years. All compliance testing shall be conducted by a laboratory which is authorized to perform calibrations traceable to the appropriate standards.

              1.2. Instrumentation for speed measurements

              The road speed of the vehicle shall be measured with instruments meeting specification limits of at least ±0,5 km/h when using continuous measuring devices.

              If testing uses independent measurements of speed, this instrumentation shall meet specification limits of at least ±0,2 km/h.

              1.3. Meteorological instrumentation

              The meteorological instrumentation used to monitor the environmental conditions during the test shall meet the specifications of:

(a) ±1 °C or less for a temperature measuring device;
(b) ±1,0 m/s for a wind speed-measuring device;
(c) ±5 hPa for a barometric pressure measuring device;
(d) ±5 % for a relative humidity measuring device.
              2. Acoustic environment, meteorological conditions, and background noise

              2.1. Test site

              2.1.1. General

              The specifications for the test site provide the necessary acoustic environment to carry out the vehicle tests documented in this Regulation. Outdoor and indoor