Council directive 92/23/EEC (repealed)Show full title

[F1 4. Interpretation of results U.K.

The measurement shall be invalid if an abnormal discrepancy between the maximum value and the other values is recorded.

4.1. Determination of test result U.K.

Reference speed V _ref used to determine the final result will be:

(i)

80 km/h for Class C1 and Class C2 tyres;

(ii)

70 km/h for Class C3 tyres.

4.2. Regression analysis of noise measurements U.K.

The (not temperature corrected) tyre-road noise level L _R in dB(A) is determined by a regression analysis according to:

• 

• where:

• is the mean value of the noise levels L _i , measured in dB(A):

• 

• n is the measurement number (n ≥ 16),

• is the mean value of logarithms of speeds v _i :

• 

• With

• 

• a is the slope of the regression line in dB(A):

• 

4.3. Temperature correction U.K.

For Class C2 tyres, the final result shall be normalised to a test surface reference temperature h _ref by applying a temperature correction, according to the following:

where θ is the measured test surface temperature,

For Class C1 tyres, the coefficient K is – 0,03 dB(A)/ ^o C when θ > θ _ref and K is – 0,06 dB(A)/ ^o C when θ < θ _ref .

For Class C2 tyres, the coefficient K is – 0,02 dB(A)/ ^o C

If the measured test surface temperature does not change by more than 5  ^o C within all measurements necessary for the determination of the sound level of one set of tyres, the temperature correction may be made only on the final reported tyre-road sound level as indicated above, utilizing the arithmetic mean value of the measured temperatures. Otherwise each measured sound level L _i shall be corrected, utilizing the temperature at the time of the sound recording.

There will be no temperature correction for Class C3 tyres.

4.4. In order to take account of any measuring instrument inaccuracies, the results according to section 4.3. shall be reduced by 1 dB(A). U.K.

4.5. The final result, the temperature corrected tyre-road noise level L _R (θ _ref ) in dB(A), shall be rounded down to the nearest lower whole value.] U.K.

Textual Amendments

F1 Inserted by Directive 2001/43/EC of the European Parliament and of the Council of 27 June 2001 amending Council Directive 92/23/EEC relating to tyres for motor vehicles and their trailers and to their fitting.