EVS-EN ISO 4871:1999

This International Standard  - gives information on the declaration of noise emission values, - describes acoustical and product information to be presented in technical   documents for the purposes of noise emission declaration, and - specifies a method for verifying the noise emission declaration.  It is applicable to machinery and equipment.  The values to be used for the purposes of noise emission declaration are either declared single-number noise emission values,  Ld, or declared dual-number noise emission values, L and K. L is a noise emission value determined directly from measurements and K is the uncertainty associated with those measurements. Ld is the sum of L and K represents an upper limit which values from repeated measurements are unlikely to exceed at a given confidence level ; Ld corresponds to the stated or labelled value, Lc, defined in ISO 7574-1.  The two forms of noise declaration are alternative means of representing any or all of the A-weighted sound power level, LWA, the A-weighted emission sound pressure level at specified positions, LpA,  and the C-weighted peak emission sound pressure level at specified positions,LpC,peak. The choice as to which of the two forms is used in a particular case depends upon the requirements to be fulfilled. This selection is made, and guidance on the values of K is given, in the appropriate noise test code.