Document ID: chunk:federal_register_of_legislation:F2024L00089:reg:800:p6
Version: federal_register_of_legislation:F2024L00089
Segment Type: reg
Provision Reference: reg 800 (pt 6/16)
Character Range: 44059–47054

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 test environments that meet the specifications of this Regulation provide equivalent acoustic environments and produce results that are equally valid.

              2.1.2. Outdoor testing

The test site shall be substantially level. For the measurement of vehicles in motion, the test track construction and surface shall meet the requirements of ISO 10844:2014. For the measurement of vehicles at a standstill, the test area shall be either:
(a)  ISO 10844:2014; or
(b)  Other dense asphalt; or
(c)  Dense concrete.
Within a radius of 50 m around the centre of the track, the space shall be free of large reflecting objects such as fences, rocks, bridges or buildings. The test track and the surface of the site shall be dry and free from absorbing materials such as powdery snow, or loose debris.
              In the vicinity of the microphones, there shall be no obstacle that could influence the acoustic field and no person shall remain between the microphone and the noise source. The meter observer shall be positioned so as not to influence the meter reading. Microphones shall be located as specified in Figures 1 of the Appendix to this annex.

              2.1.3. Indoor hemi anechoic or anechoic testing

              This paragraph specifies conditions applicable when testing a vehicle, either operating as it would on the road with all systems operational, or operating in a mode where only the AVAS is operational.

              The test facility shall meet requirements of ISO 26101:2012 with the following qualification criteria and measurement requirements appropriate to this test method.

              Space to be deemed hemi-anechoic shall be defined as shown in Figure 3 of the Appendix to this annex.

              For qualifying the hemi acoustic space, the following evaluation shall be conducted:

(a) Sound source location shall be place on the floor in middle of the space deemed to be anechoic;
(b) Sound source shall provide a broadband input for measurement;
(c) Evaluation shall be conducted in one-third-octave bands;
(d) Microphone locations for evaluation shall be on a line from the source location to each position of microphones used for measurement in this Regulation as shown in Figure 3 of the Appendix to this annex. This is commonly referred to as the microphone transverse;
(e) A minimum of 10 points shall be used for evaluation on the microphone transverse line;
(f) The one third octave bands used to establish hemi-anechoic qualification shall be defined to cover the spectral range of interest.
              The test facility shall have a cut-off frequency, as defined in ISO 26101:2012,