DNV 109

This Ecma Standard applies to information technology andtelecommunications equipment.

This Ecma Standard specifies:

• the method of determining the declared noise emission valuesof a batch of machines,

• acoustical and product information to be given in technicaldocuments supplied to users by the manufacturer,

• the method for verifying the declared noise emission valuesgiven by the manufacturers.

The uniform methods in this Ecma Standard use the noise emissiondata obtained in accordance with ECMA-74, and the proceduresspecified in ISO 4871 [4] and the ISO 7574 series.

The basic declared noise emission values are the declaredA-weighted sound power level LWAd (a statistical maximum valuecorresponding to Lc in ISO 7574-1) and the declared A-weightedemission sound pressure level L_pAm (a meanvalue) at the operator or bystander positions.

The declared A-weighted sound power levelL_WAd permits comparison of noise emissionsbetween different products and permits predictions of installationor work-place noise immission levels, as described in ECMA TR/27[8].

Although the most useful quantity for calculating immissionlevels due to one or more sound sources is usually the declaredA-weighted sound power level of the individual source(s), thedeclared A-weighted emission sound pressure levelL_pAm may be used to estimate the immissionlevel in the immediate vicinity of an isolated piece ofequipment.

To avoid confusion between sound power levels and emission soundpressure levels, the A-weighted sound power level is declared inbels and the A-weighted emission sound pressure level is declaredin decibels.

Edition:

5

Published:

12/01/2010

Number of Pages:

24