Document ID: chunk:federal_register_of_legislation:F2021C00509:front:0:p46
Version: federal_register_of_legislation:F2021C00509
Segment Type: other
Provision Reference: 
Character Range: 133630–136511

on the side which gives the maximum possible distance between the microphone and the outline of the motorcycle (handlebars excluded).
         If the exhaust system has more than one outlet at centres less than 0.3 m apart, the microphone shall be faced towards the outlet which is nearest the motorcycle
         (handlebars excluded) or towards the outlet which is highest above the surface of the track. If the centres of the outlets are more than 0.3 m apart, separate measurements shall be taken for each of them, the highest figure recorded being taken as the test value.

2.4.3. Operating conditions

         The engine speed shall be held steady at one of the following values:
         S/2 if S is more than 5,000 rpm,
         3S/4, if S is not more than 5,000 rpm
         where S is the speed specified under item 9 of annex 1.
         When a constant engine speed is reached, the throttle shall be returned swiftly to the idle position. The sound level shall be measured during an operating cycle consisting of a brief period of constant engine speed and throughout the deceleration period, the maximum sound-level meter reading being taken as the test value.

2.5. Results

         2.5.1. The Communication referred to in Annex 1 shall indicate all relevant data and
          particularly those used in measuring the noise of the stationary motorcycle.

         2.5.2. Values, rounded off to the nearest decibel, shall be read off the measuring instrument.
         If the figure following the decimal point is between 0 and 4, the total is rounded down and if between 5 and 9, it is rounded up.
         Only those measurements which vary by no more than 2 dB(A) in three consecutive tests will be used.

2.5.3. The highest of the three measurements will constitute the test result.

Annex 3 – Appendix

Figure 1
Test for vehicle in motion

Figure 2
Test for stationary vehicle

Annex 4

SPECIFICATIONS FOR THE TEST SITE

1. Introduction

           This annex describes the specifications relating to the physical characteristics and the laying of the test track. These specifications, based on a special standard,[22]/ describe the required physical characteristics as well as the test methods for these characteristics.

2. Required characteristics of the surface

           A surface is considered to conform to this standard provided that the texture and voids content or sound absorption coefficient have been measured and found to fulfil [all] the requirements of paragraphs 2.1. to 2.4. below and provided that the design requirements (para. 3.2.) have been met.

2.1. Residual voids content

           The residual voids content, Vc, of the test track paving mixture shall not exceed 8 per cent. For the measurement procedure, see paragraph 4.1.

2.2. Sound absorption coefficient

           If the surface fails to conform to the residual voids