Document ID: chunk:federal_register_of_legislation:F2021C00509:front:0:p17
Version: federal_register_of_legislation:F2021C00509
Segment Type: other
Provision Reference: 
Character Range: 53424–56374

sound measurement interval and shall be recorded during each test run.
            Values representative of temperature, wind speed and direction, relative humidity, and barometric pressure shall be recorded during the sound measurement interval.

           2.1.3. The A-weighted sound level of sound sources other than those of the vehicle to be tested and of wind effects must be at least 10dB(A) below the sound level produced by the vehicle.

           2.2. Vehicle

           2.2.1. Measurements shall be made on unladen vehicles and, except in the case of nonseparable vehicles, without trailer or semi-trailer.

           2.2.2. The tyres used for the test are selected by the vehicle manufacturer and shall comply with commercial practice and be available on the market; they shall correspond to one of the tyre sizes designated for the vehicle by the vehicle manufacturer and meet the minimum tread depth of 1.6mm in the main grooves of the tread surface.
            The tyres must be inflated to the pressure(s) appropriate to the test mass of the vehicle.

           2.2.3. Before the measurements are started, the vehicle shall be brought to its normal operating conditions as regards:

           2.2.3.1. temperatures

           2.2.3.2. tuning

           2.2.3.3. fuel

           2.2.3.4. sparking plugs, carburettor(s), etc., (as appropriate).

           2.2.4. If the vehicle is fitted with more than two-wheel drive, it shall be tested in the drive which is intended for normal road use.

           2.2.5. If the vehicle is fitted with fan(s) having an automatic actuating mechanism, this system must not be interfered with during the measurements.

           2.2.6. If the vehicle is equipped with an exhaust system containing fibrous materials, the exhaust system is to be conditioned before the test according to annex 5.

           3. METHODS OF TESTING

           3.1. Measurement of noise of vehicles in motion

           3.1.1. General conditions of test (see appendix, fig. 1)

           3.1.1.1. At least two measurements shall be made on each side of the vehicle. Preliminary measurements may be made for adjustment purposes, but shall be disregarded.

           3.1.1.2. The microphone must be located at a distance of 7.5 +/- 0.2 m from the reference line CC' (Figure 1) of the track and 1.2 +/- 0.1 m above the ground. Its axis of maximum sensitivity must be horizontal and perpendicular to the path of the vehicle (line CC').

           3.1.1.3. Two lines, AA' and BB', parallel to line PP' and situated respectively 10 m forward and 10 m rearward of that line shall be marked out on the test runway.
            The vehicle shall be driven in a straight line over the acceleration section in such a way that the longitudinal median plane of the vehicle is as close as possible to the line CC' and approach line AA' at a steady speed as specified below. When the front of the vehicle reaches the line