Document ID: chunk:federal_register_of_legislation:F2006L01279:body:0:p11
Version: federal_register_of_legislation:F2006L01279
Segment Type: other
Provision Reference: 
Character Range: 30246–31801

one. The noise level of the vehicle shall be the higher or highest noise level so calculated.
    3.4.4   If the microphone position is less than 1m from the engine compartment of the vehicle the calculated noise level shall be reduced by 2dB(A) unless the provisions of paragraph 3.4.5 have been invoked.
    3.4.5   Where the mechanical noise of the vehicle (for example engine or transmission noise) can be shown to increase the measured noise level by 2dB(A) or more, special acoustic shielding may be fitted to mask this source so that the test is carried out on the exhaust noise alone.
3.4.5.1 Such shielding shall not interfere with the normal acoustic properties of the
'Noise Reduction System'.
3.4.5.2 Where such shielding is used both noise levels (with and without the shielding)
    shall be reported. The noise level with the shielding in place shall be used to assess the vehicle's compliance.
3.4.5.3 Where such shielding is used the provisions of paragraph 3.4.4 shall not apply.

4.  TEST SITE LAYOUT AND TYPICAL MICROPHONE LOCATIONS
    4.1              Vehicle in motion
    4.2
    Stationary Vehicles
[1] A test is made on a stationary vehicle in order to provide a reference value for administrations which use this method to check vehicles in use.
[2] This condition shall be considered satisfied in the case of a positive-ignition engine when the angle of opening of the throttle is 90 per cent and in the case of a 'Diesel Engine' when the movement of the feed rack of the injection pump is limited to 90 per cent of its stroke.