IS0 4871:1996 pdf download – Acoustics – Declaration and verification of noise emission values of machinery and equipment.
3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 machinery and equipment: An assembly of linked parts or components with the appropriate ac- tuators, control and power circuits, etc., joined to- gether for a specific application. Also included in this definition is an assembly of machines which, in order to achieve the same end, are arranged and controlled so that they function as a whole. 3.2 family of machinery or equipment: Machinery or equipment of similar design or type, intended to perform the same functions. 3.3 batch (lot) of equipment: A number of units of machinery or equipment of the same family produced in quantity, manufactured to the same technical specifications and characterized by the same declared noise emission values. NOTE 1 series or a portion thereof. The batch may be either an entire production 3.4 operating mode: A condition in which the ma- chinery or equipment is performing its intended func- tion for the purpose of determining its noise emission values. 3.5 emission: Airborne sound radiated by a well- defined noise source (e.g. the machine under test) under specified operating and mounting conditions.
5 In general, the subscripts “eq” and “T” are omitted since time-averaged emission sound pressure levels are necessarily determined over a certain measurement time i nte rva I. 6 Equation (1 ) is identical to that for the familiar IS0 envi- ronmental noise descriptor “equivalent continuous sound pressure level” defined in I S0 1996-1. However, the emis- sion quantity defined above is used to characterize the noise emitted by a machine under test and assumes that stan- dardized measurement and operating conditions as well as a controlled acoustical environment are used for the measurements. 3.9 sound power, W: The rate per unit time at which airborne sound energy is radiated by a source. It is expressed in watts. 3.10 sound power level, b: Ten times the logar- ithm to the base 10 of the ratio of the sound power radiated by the source under test to the reference sound power. It is expressed in decibels. The frequency weighting or the width of the fre- quency band used shall be indicated. The reference sound power is 1 pW (lo-” W). NOTE 7 For example, the A-weighted sound power level is &VA. 3.11 noise emission value: A general term by which any one or more of the A-weighted sound power level, kA, or the A-weighted time-averaged emission sound pressure level, LpA, or the C-weighted peak emission sound pressure level, LpC,peak, is in- ferred.