1、INTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXAYHAPOAHAR OPrAHMSAuMR no CTAHAAPTM3Ai - acoustical and product information to be given in tech- nical documents supplied to users by the manufacturer; - the method for verifying the
2、 declared noise emission values given by the manufacturers. The uniform methods in this International Standard use the noise data obtained in accordance with IS0 7779 and the pro- cedures specified in IS0 4871 and IS0 7574. The basic declared noise emission values are the declared A-weighted sound p
3、ower level, LWd (a statistical maximum value corresponding to L, in IS0 75741, and the declared A-weighted sound pressure level, Lpm (a mean value), at the operator or bystander positions. 1 COPYRIGHT International Organization for StandardizationLicensed by Information Handling ServicesIS0 9296 : 1
4、988 (EI The declared A-weighted sound power level, L IVAd, permits comparison of noise emissions between different products and permits predictions of installation or workplace noise exposure levels 1). Although the most useful quantity for calculating exposure levels due to one or more sound source
5、s is usually the declared A-weighted sound power level of the individuai source(s), the declared A-weighted sound pressure level, Lpnm, may be used to estimate the exposure level in the immediate vicinity of an isolated piece of equipment. To avoid confusion between sound power levels and sound pres
6、sure levels, the A-weighted sound power level is declared in bels and the A-weighted sound pressure level is declared in decibels. 2 References IS0 4871, Acoustics - Noise labelling of machinery and equipment. IS0 7574-1, Acoustics - Statistical methods for determining and verfiing stated noise emis
7、sion values of machinery and equipment - Part I: General considerations and definitions. IS0 7574-2, Acoustics - Statistical methods for determining and verifying stated noise emission values of machinery and equipment - Part 2: Methods for stated values for individual machines. IS0 7574-4, Acoustic
8、s - Statistical methods for determining and verifying stated noise emission values of machinery and equipment - Part 4: Methods for stated values for batches of machines. IS0 7779, Acoustics - Measurement of airborne noise emitted b y computer and business equipment. 3 Definitions For the purposes o
9、f this International Standard, the following definitions apply. They are grouped in three categories : general definitions, acoustical definitions and statistical definitions. 3.1 General definitions 3.1.1 computer and business equipment: Equipment, and components thereof, used primarily in computer
10、 installations, off ices or similar environments. 3.1.2 batch lot of equipment: A number of units of com- puter or business equipment intended to perform the same function produced in quantity, manufactured to the same technical specifications and characterized by the same declared noise emission va
11、lues. NOTE - The batch may be either an entire production series or a portion thereof. 3.1.3 idling mode: A condition specified in IS0 7779 in which the equipment, after any necessary warm-up period, is energized but is not operating. 3.1.4 operating mode: A condition in which the equipment is perfo
12、rming its intended function as specified in IS0 7779. If more than one operating condition is applicable, the condition which is typical for the majority of the applications shall be used. 3.2 Acoustical definitions 3.2.1 A-weighted sound power level, LLVA, in decibels: The sound power level of the
13、equipment, determined in accord- ance with IS0 7779, with A-weighting. The reference sound power is 1 pW. 3.2.2 A-weighted sound pressure level, Lp, in decibels: The sound pressure level of the equipment with A-weighting, determined in accordance with IS0 7779 at the operator pos- ition(s1, or at th
14、e bystander positions if no operator position is specified. The reference sound pressure is 20 pPa. 3.2.3 measured value : The value of the A-weighfed sound power level, L, or the A-weighted sound pressure level, Lp, determined from measurements on an individual machine in accordance with IS0 7779.
15、Measured values shall not be rounded. 3.2.4 declared noise emission values: The value of the declared A-weighted sound power level, LkVAd, or that of the declared A-weighted sound pressure level, LpAm, or both. 3.2.5 declared A-weighted sound power levei I, LWAd, in bels: The value of the A-weighted
16、 sound power level, LIVA, divided by 10 declared for an individual machine .or for all machines in a batch. The deciared value indicates the limit below which the A-weighted sound power level, L, divided by IO, of the individual machine and/or a specified large pro- portion of the A-weighted sound p
17、ower levels, L FV, divided by IO, of the batch of machines are stated to lie when the machines are new. The verification procedures in clause 6 are designed such that there is 95 % probability of acceptance if no more than 6,5 % of the equipment in a batch has A-weighted sound power levels greater t
18、han the declared noise emission value i,. The value of LvA is rounded to the nearest tenth of a bel. NOTE - LFr/Ad corresponds to L, in IS0 7574. 3.2.6 declared A-weighted sound pressure level, Lp, in decibels: The value of the A-weighted sound pressure level, Lp, declared for an individual machine
19、or the arithmetic mean of the values of the A-weighted sound pressure level, LP, declared for a batch of machines, when new. The measure- ment positions) for LPA is (are) the operator position(s) defined in IS0 7779 or the bystander positions if no operator position is specified. 1) If the declared
20、A-weighted sound power level, LWAd., in bels (B), is to be used for the determination of installation noise levels, or for comparison with the declared A-weighted sound power levels in decibels (dB for machines other than computer and business equipment, the value of LyVAd in bels is multiplied by t
21、en to obtain its value in decibels, using the identity 1 B = 10 dB. 2 COPYRIGHT International Organization for StandardizationLicensed by Information Handling Services- 9296-88 4851903 0067838 3r IS0 9296 : 1988 (E) 3.3 Statistical definitions NOTE - In this International Standard, the symbol O is u
22、sed for a true standard deviation and the symbol s for an estimated standard deviation. 3.3.1 standard deviation of repeatability, or : The stan- dard deviation of measured values obtained under repeatability conditions, .e. the repeated application of the same noise emission measurement method (IS0
23、 7779) on the same equip- ment within a short interval of time under the same conditions (same laboratory, same operator, same apparatus). 3.3.2 standard deviation of reproducibility, oR : The stan- dard deviation of measured values obtained under repro- ducibility conditions, .e. the repeated appli
24、cation of the same noise emission measurement method (IS0 77791 on the same equipment at different times and under different conditions (different laboratory, different operator, different apparatus). The standard deviation of reproducibility, therefore, includes the standard deviation of repeatabil
25、ity. 3.3.3 standard deviation of production, op : The standard deviation of measured values obtained on different equipment from batches of the same family, using the same noise emis- sion measurement method (IS0 7779) under repeatability con- ditions (same laboratory, same operator, same apparatus)
26、. 3.3.4 total standard deviation, ot : The square root of the sum of the squares of the standard deviation of reproducibility and the standard deviation of production given by the following formula : 3.3.5 reference standard deviation, OM : The total stan- dard deviation specified for computer and b
27、usiness equipment which is considered typical for batches of this equipment. The reference standard deviation for LWA shall be QM = 2,O dB. NOTE - The use of a fixed value for OM enables the application of a statistical method to deal with small sample sizes. If the total standard deviation, ut, is
28、different from the reference standard deviation, OM, the manufacturer should estimate his risk of rejection on the basis of both standard deviations ot and OM (see 4.4.1). 4 Determination of the declared noise emission values 4.1 General Declared noise emission values, LwAd and Lpm, shall be determi
29、ned for the idling mode and the operating mode. If the machine has more than one operating or idling mode, the modes which are typical of the majority of the applications shall be used. 4.2 Determination of the A-weighted sound power level, LWA The A-weighted sound power level, LWA, shall be determi
30、ned in accordance with IS0 7779. NOTE - Measured values should not be rounded. The precision of measured values should be consistent with the calculations to be per- formed in accordance with this International Standard. 4.3 Measurement of the A-weighted sound pressure level, Lp, at the operator (by
31、stander) position(4 The A-weighted sound pressure level, LpA, at the operator position(s) shall be measured in accordance with IS0 7779. If no operator position is specified, LP shall be determined by energy-averaging the measured values at the four bystander positions at the front, rear, right and
32、left sides of the equipment in accordance with IS0 m9. 4.4 Determination of the declared noise emission values NOTE - The determination of the declared noise emission values is the sole responsibility of the producer. 4.4.1 power level, LWAd, for batches of machines To obtain the declared A-weighted
33、 sound power level, LbVAd, for batches of machines, the producer shall take into account the following : Determination of the declared A-weighted sound a) The uncertainty of the measurement with respect to the accuracy of the measurement method (IS0 77793, consider- ing reproducibility. The standard
34、 deviation of repro- ducibility, CR, for LA is estimated to be 1,5 dB. b) The production variation, Le. measurements on many machines from one batch carried out in accordance with IS0 7779 in one laboratory under conditions as identical as possible (repeatability conditions). For each machine, the m
35、ean value from two measurements is determined. These values are used to estimate the standard deviation of pro- duction for the batch. c) The total standard deviation, crt, for values of L,A as a combination of the standard deviation of reproducibility, oR, and the standard deviation of production,
36、op. d) The procedures for verifying the declared noise emis- sion values as given in clause 6, which are consistent with IS0 7574-4 : the single sampling inspection procedure with a sample size, n, equal to 3 and a reference standard devia- tion CM = 2,O dB. If a reasonably large sample is available
37、, the following pro- cedure shall be used. Determine the value, LwA, of the A-weighted sound power level for each individual machine in the sample in accordance with IS0 7779. Calculate the arithmetic mean, L, of the LWA values using the following formula : i =1 where n is the number of machines in
38、the sample. 3 COPYRIGHT International Organization for StandardizationLicensed by Information Handling Services-_ 9296-88 I4853903 0067839 5 I IS0 9296 : 1988 (E) Calculate the standard deviation of production, sp, from the measured Llv; values in the sample : Calculate the total standard deviation,
39、 s, from the standard deviation of production, spi and the standard deviation of reproducibility, sR (estimated to be 1,5 dB) using the following formula : s, = dm NOTES 1 The values of LIA, and s, are estimates of the true mean value, p, and the true total standard deviation, o, of the batch. 2 If
40、a reasonably large sample is not available, the value of st may be estimated from previous experience. Determine the declared A-weighted sound power level, LlVAd, rounded to the nearest tenth of a bel, from the values of LWAm and st using the following formula : NOTE - This equation is based on IS0
41、7574-4 and results in a 5 % risk of rejection. 4.4.2 Determination of the declared A-weighted sound power level, LlvAd, for an individual machine Determine the declared A-weighted sound power level for an individual machine from the measured A-weighted sound power level, Lbv, using the following rel
42、ation : The value of K in the relation above accounts for the random measurement errors occurring under reproducibility conditions. A value of K equal to 2,5 dB is appropriate for a 5 % risk of re- jection for SR = 1,5 dB. The value of Lkv,t,d for an individual machine is rounded to the nearest tent
43、h of a bel. 4.4.3 Determination of the declared A-weighted sound pressure level, Lprn, for batches of machines Determine the declared A-weighted sound pressure level, Lp, for the batch of machines by calculating the arithmetic mean of the A-weighted sound pressure levels, LP, for the machines in the
44、 sample, measured at the operator position or bystander positions in accordance with 4.3. The value of Lp, is rounded to the nearest whole number of decibels. 4.4.4 Determination of the declared A-weighted sound pressure level, Lprn, for an individual machine The declared A-weighted sound pressure l
45、evel, L,A, for an in- dividual machine is equal to the value of the A-weighted sound pressure level, Lp, measured at the operator position or bystander positions in accordance with 4.3. The value of LpAm is rounded to the nearest whole number of decibels. 5 Presenting declared noise emission values
46、The presentation of noise emission values for a product, deter- mined in accordance with this International Standard, shall contain the following information : a) the words “DECLARED NOISE EMISSIONS in accord- ance with is0 9296“ followed by the values of LWAd and Lp,t, as determined by the procedur
47、es in clause 4 for both operating and idling modes, where applicable, for batches of machines or individual machines, and indication of the identity 1 B = 10 dB; b) identification of whether the value of Lp,t,rn as defined in IS0 “9 refers to the operator position or bystander positions ; c) if the
48、machine has more than one operating mode, suf- ficient information to identify unambiguously the mode used for the declaration; d) identification of the product with sufficient detail to determine the applicability of the declared noise emission values. If such information is not given, the declared
49、 noise emission values apply to all variations of the listed product. Declared noise emission values shall be given in technical docu- ments or other literature supplied to the user (see annex A). 6 Verification of the declared noise emission values 6.1 General The procedures for verifying the declared noise emission values are applicable only to declared A-weighted sound power levels, LWAd, and are not applicable to declared A-weighted sound pressure levels, Lprn. The procedure for verifying the values of LWAd of the batch is consiste
