xmlns:atom="http://www.w3.org/2005/Atom" xmlns:atom="http://www.w3.org/2005/Atom"
Textual Amendments
The measurement shall be invalid if an abnormal discrepancy between the maximum value and the other values is recorded.
Reference speed V ref used to determine the final result will be:
80 km/h for Class C1 and Class C2 tyres;
70 km/h for Class C3 tyres.
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),
With
a is the slope of the regression line in dB(A):
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.