BS EN 415-9:2009 pdf free download – Safety of packaging machines Part 9: Noise measurement methods for packaging machines, packaging lines and associated equipment, grade of accuracy 2 and 3.
4) Whenever the previous methods cannot be employed, EN ISO 11204 is employed if the environmental conditions allow for its application with Grade 2 (engineering grade) accuracy.
5) Grade 3 (survey grade) methods are employed when the conditions previously set for the application of grade 2 (engineering) methods cannot be fulfilled. However, survey grade methods could also be employed when operating conditions of the machines do not allow for long measurement times, e.g. due to lacking of product to be processed or to other operational limitations during the test.
6) The standard EN ISO 11204 takes into account the case of sound sources with strong directivity. When the sound source is not highly directive, the standard EN ISO 11202 is applicable. However, these standards operate correctly only under strict conditions of diffuse sound field. If the sound field is not perfectly diffuse, the evaluation of environmental correction factor ‘<2 and of local environmental correction factor K3 is possible following the guidance given in Annex B. 7) When the background noise is very high, or the environmental correction factor is a great number, or the sound field is not complying with the assumption of a diffuse field, the only way of estimating the emission pressure level at the work station is to measure the sound power level of the machine employing the sound intensity method (EN ISO 9614-2) with survey grade and to derive the sound pressure level at the work station by means of EN ISO 11203. NOTE 1 The diffuse field occurs when, in the test environment, the sound waves are repeatedly reflected in all directions with equal magnitude and probability (e.g. industrial environment with flat and smooth ceiling and walls). NOTE 2 The directive source occurs when the emission sound pressure level of the source is mainly headed in only one direction. In this case, the following options are available: 1) If the manufacturer is only responsible of the noise emitted by the single machine, the only viable method is to determine the sound power level by applying the sound intensity measurement method as described in EN ISO 9614-2 and deriving the emission sound pressure level at the work station by employing EN ISO 11203. 2) If the machine is supplied together with the other components of the production line, then the noise emission of these other components should not be considered part of the background noise. The measurement of the background noise will be performed with the whole production line not in activity. 3) If only part of the other components of the production line is supplied with the machine under test, it is necessary to estimate the background noise caused at the work station by the part of the components of the production line which are not being supplied together with the machine under test. This estimate can only be done by knowing the sound power level emitted by each of these components, and employing EN ISO 11203 for estimating the sound pressure level at the work station caused by these components.