Statistical Factors Affecting Machinery Noise Emission Declarations


  • Stephen E. Keith Health Canada, Radiation Protection Bureau, 775 Brookfield Rd. 6301B, Ottawa, ON, K1A ICI
  • Stephen H.P. Bly Health Canada, Radiation Protection Bureau, 775 Brookfield Rd. 6301B, Ottawa, ON, K1A ICI


Acoustic noise, ISO 4871, measurement of noise emission


Occupational noise-induced hearing loss is a significant public health problem in Canada. To help reduce workplace noise, purchasers of machinery need to be able to make meaningful comparisons of machinery noise emissions with: (i)emissions from other machines, (ii)purchase specifications and (iii)occupational noise limits. This can be achieved if technical specifications and instruction manuals for machinery contain noise emission declarations; realistic, but conservative, estimates of the sound pressure levels and sound power levels emitted by machine(s) under standard conditions. Guidelines for machinery noise emission declarations in Canada are being prepared by the Canadian Standards Association (CSA). They are based, in part, on ISO 4871, one of a series of international standards that can be used as an efficient way to either meet European regulatory requirements for noise emission declarations or to verify declarations. he purpose of this study was to examine the implications of using ISO 4871 for the declaration and verification of the noise emission values of machinery manufactured in batches. For measurement of noise emission values to be feasible, the values must be based on measurements of a relatively small sample of machines from the batch. From health and safety considerations, it is important that there be a reasonably high probability that the noise emission value of machinery purchased for a workplace will not exceed the declared value. For the benefit of the manufacturer, there should also be a relatively high probability that a noise emission declaration for a batch will be verified, either by a purchaser or a regulatory authority. Therefore, this study examined the dependence of these probabilities on three factors: (i) the number of machines used to determine a noise emission declaration, (ii) reproducibility of the measurements and (iii) the difference between the total standard deviation and the reference standard deviation of the measurements.

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How to Cite

Keith SE, Bly SH. Statistical Factors Affecting Machinery Noise Emission Declarations. Canadian Acoustics [Internet]. 2000 Dec. 1 [cited 2024 Jun. 13];28(4):34-5. Available from:



Proceedings of the Acoustics Week in Canada