Volume 6, Number 4, December, 1998 - Noise News International

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standards. One of the functions of these standards is to help determine the "state of the art" methods which ED directives and national regulations implicitly require should be used in the development of noise control measures. The majority of the necessary framework standards (A and B standards) concerned with noise monitoring and noise control are already in place. Guidelines are also available for the development of machine-specific noise measurement standards and for the preparation of noise control sections of machine-specific, general safety standards. However, time has not been adequate to allow the provisions of these framework noise standards to be properly transposed into the large number of machine-specific safety standards (C standards) which are under development. Standardization Activities in the Field of Noise Control In Germany, national standardization related to noise control is the task of the NA Akustik Larmminderung und Schwingungstechnik (NALS) standards committee which proposes and develops standards and technical regulations and places its members on relevant committees of the European Committee for Standardization (Comite europeen de normalisation - CEN) and the International Organization for Standardization (Organisation Internationale de Normalisation - ISO). At the international level, noise control standards are prepared in the technical committees ISOrrC 43, Acoustics, and CENrrC 211, Acoustics. The task areas of these technical committees are similar to those ofNALS. In order to ensure uniform conditions for competition on the international market, acoustical standards are nearly always prepared at the ISO level first and then adopted by CEN. Acoustics and noise control should be seen as a sub-task of designers of machinery, buildings, work sites, workplaces, and electro-acoustic systems. During the preparation of standards, close cooperation is necessary between experts in acoustics and experts in other specialty areas (e.g., mechanical engineering, electrical engineering) at national, European, and intemationallevels. Existing Standards The Standardization Concept The standardization concept for noise control is based on German legal requirements and ED directives; the specifications contained in standards supplementthe safety objectives specified in legislation. Above all, noise control starts with some form of redesign of, or change to, a workplace or part of it (e.g., with the procurement or modification of plant), an item of machinery, an operating procedure, or a work room. Legal requirements call for state-of-the-art noise control measures, i.e., minimum sound production at the source and, where technically feasible, maximum sound level reduction during transmission, in order to keep noise immission at the workplace as low as possible. However, planning for compliance with these requirements presupposes that the parameters have been agreed to for quantifying noise emissions (from machinery and equipment, transport vehicles, etc.), for assessing sound insulation products (e.g., enclosures, screens, etc.), and for determining sound level reduction in buildings and workrooms. Table 1 shows the elements to be considered and the relevant noise control parameters. To plan for compliance, standards have been developed which specify measurement and assessment methods and provide for the design of noise reduction measures for machines, sound insulation products, construction products, etc. An effective division has developed in standardization between framework standards and specific user standards: • Framework standards specify and describe methods for the measurement of emissions from sources, for sound level reduction through use of insulation in work-rooms, and for general principles of assessment, prediction and design; • Standards specific to certain types ofmachinery and other sector-specific industry standards Work system elements Sound sources • Machines Table 1: Standardization concept • Means of conveyance • Operating procedures • Tools • Means of transport Sound insulation products • Enclosures • Sound screens • Sound absorbers Hearing protectors Buildings • Ceilings, walls, windows, doors Workrooms • Sound absorption • Noise screens Relevant noise control parameters Emission values Sound power level Emission sound pressure level at the workplace Insertion loss Sound reduction index Sound propagation • sound level reduction • sound level increase Background noise 202 NoiselNewsInternational 1998 December
specify in more detail relevant measurement methods, application-related assessment criteria, and design measures. Framework Standards and Safety Standards Specific to Machinery The framework standards (A or B standards) that have been developed for machinery safety - EN 292-l 6 and EN 292-2,6 and EN 414 7 - specify principles for detecting and avoiding hazards and for increasing machinery safety. With regard to acoustics, there are framework standards (B standards) for determination of sound emission and for an explanation of principles of noise reduction of machines and the implementation of those principles: EN ISO 3740 ff,8 EN ISO 11200 ff,9 EN ISO 4871,10 EN ISO 12001,11 EN ISO 11688,12 EN ISO 11689,13 EN ISO 11690. 14 The machine safely standards and an explanation of their purpose are given in Table 2. Appropriate safety standards (C standards) are prepared in support of the ED machinery directive for different groups of machines based on the framework standards. According to EN 414, these framework safety standards should contain: Type A Table 2: Machine safety standards: noise control Framework standards: basic principles EN 292, EN 414 Type B Framework standards: individual hazards Sound emission • Measurement - Guide - Sound power Level - Emission sound pressure level - Declaration and verification • Reduction • Value ranges EN ISO 12001 EN ISO 3740 to 47, 9614 EN ISO 11200 to 04 EN ISO 4871 EN ISO 11688-1 EN ISO 11689 Safety standards Noise emission specific to machinery test codes Dealing with the hazard of noise according to EN 1746 • Safety requirements • noise - noise reduction • Checking safety requirements • noise - sound measurement - emission value range - achievable value • Information for the machine user • noise - noise data, noise measurement - additional noise reduction measures Example: EN 691 wood working machines ISO 7960 EN 710 foundry machines EN 1265. • A description of the hazards concerned, • the safety objectives to be achieved, • the safety requirements and/or measures for reducing hazards, • the test methods which can be used to establish compliance with the safety requirements contained in the standard, and • user information. These machine-specific safety standards therefore have an important practical role: they are the means by which the noise control requirements of the machinery directive are to be specified. Standards EN 414 and EN 292-1 describe a series of noise hazards leading to, for example, hearing loss, tinnitus, stress and impairment of verbal communication. If significant hazards of this kind are caused by a machine, noise must be taken into account in the development of the safety standard specific to that type of machine. In general, this is necessary if a machine is associated with an emission sound pressure level of LpA =70 dB or more. Draft standard EN 1746 15 prescribes the necessary provisions on noise which should be included in such machine-specific, general safety standards. According to this draft standard, where a noise hazard may exist, a machine-specific safety standard should: • Classify noise in the list of hazards, • name the machine's main noise sources, • refer to principles of low-noise design (according to ISO TR 11688-1), give concrete examples of noise control by design, describe the use of sound insulation products (enclosures, etc.), and emphasize the importance of sound emission level as the main criterion for selection of low-noise machines, • emphasize the importance of determining noise emission levels to facilitate monitoring of the machine design process, • compile machine emission value ranges for one machine type (to EN ISO 11689) and deduce attainable values if possible, • develop the information necessary for user instructions (to EN ISO 11690-1 and -2) so as to allow for low-noise operation, e.g., installation of dampers, adaptation to low-noise operating conditions, maintenance to ensure low-noise operation, and recommendation of additional equipment (enclosures, noise screens and, if necessary, hearing protectors), and • specify noise data for user instructions and technical documents. If there is no significant hazard caused by noise for a group of machines, then the section on noise can be limited. However, it must at 1998 December NoiselNews International 203
Page 1 and 2: Volume 6, Number 4 1998 December IN
Page 3 and 4: Editorial Stllff G. Maling, Jr., Ma
Page 5 and 6: Anechoic Chambers with EMW lining T
Page 7 and 8: "Finally, an Outdoor Sound Propagat
Page 9 and 10: YOUR NEXT SOUND METER • Workplace
Page 11: Feature Noise Control Standards for
Page 15 and 16: c: o .~ "E f---7""'lf-1I:-i~;J4'.--
Page 17 and 18: References 1. Council Directive 89/
Page 19 and 20: Feature Advances in Acoustical Stan
Page 21 and 22: (a) M 4 6:~f=========::::CI~ Fig. 3
Page 23 and 24: Adaptor for Microphone & Preamplifi
Page 25 and 26: the last twenty years and be ready
Page 27 and 28: CONTROL The illustrations in thisfe
Page 29 and 30: Application to machines with connec
Page 31 and 32: Application with a thin screen. Exa
Page 33 and 34: Application with light single walls
Page 35 and 36: European News A. Cops, European Edi
Page 37 and 38: Pan-American News George Maling, Pa
Page 39 and 40: Contest entry forms and other mater
Page 41 and 42: Newly published ISO and IEC Standar
Page 43 and 44: ACOUSTICS ANSI Sl.15-1997-Part 1, M
Page 45 and 46: NNI Directory Organizational and Ed
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Volume 6, Number 4, December, 1998 - Noise News International

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