What the legislation requires for vibration certification …

Rome, Apr 15 – The need to decide vibration emission level of the machinery placed on the market were born in accordance with the requirements of the Machinery Directive, Directive 2006/42 / EC of 17 May 2006.

This Directive “in fact only authorizes the placing on the market of machinery which complies with all the safety requirements in force at that time. Manufacturers are required, in addition to other data, to indicate the noise and vibration levels of the machinery they produce turnover”.

To remember it in these terms and provide various information about vibration certification of the machines It’s on risk of vibration is the document “Acoustic and vibration certification of machines. Operational Manual “which, prepared by the Department of Medicine, Epidemiology, Occupational and Environmental Hygiene (DIMEILA) in Inail, can be a useful tool to reduce the risks provided for in Legislative Decree 81/2008.

After speaking in recent months and presenting the Inail document on acoustic certification, today we focus on vibration certification with special reference to the following topics:

Machinery Directive and general criteria for risk reduction

The document describes the basic points regarding the risk of vibrations, as reported inAnnex I to Directive 2006/42 / EC.

We resume the general criteria (1.5.9) in the appendix:

The machine must be designed and constructed in such a way that the risks due to the vibrations transmitted by the machine are reduced to a minimum level, taking into account the technical development and the availability of means to reduce the vibrations, especially at the source. The level of vibration emission can be assessed on the basis of the comparative emission data for similar machines.

These criteria relate to “the risk associated with the exposure of vibrations generated both by the machine itself or by some of its components during operation (eg due to rotations, aerodynamic phenomena or the impact of portable machines with resistant materials) and due to to the interaction of the machine with the surrounding environment (such as an operating machine moving on uneven ground) “.

Remember toexposure to vibrations “Can be transmitted to the whole body through the feet or sitting and can cause or aggravate any musculoskeletal disorders (back pain or back injuries), while exposure of the hand-arm system can cause damage to the blood vessels in fingers and hands (white) finger syndrome) and damage to it peripheral nervous system, tendons, muscles, bones and ligaments ”.

However, it is necessary to “distinguish between exposure to vibrations of the person and vibration emissions from machines”: “the daily exposure of humans to vibrations can not only be deduced from the vibration emission value of the machine, as it also depends on the duration of the machine and conditions of use; for national acts implementing Directive 2002/44 / EC on exposure of workers to the risks arising from vibration.

In any case, operators have an interest in “choosing machines with a low vibration level, as it is easier to comply with the exposure limits specified in the legal reference”.

Eventuallymanufacturer’s approach to prevent the risk of exposure to vibration must follow “principles of security integration“(Also presented in the article” Noise Hazard: Acoustic Certification and the Machinery Directive “) and” take into account the following principles:

  • must be prioritized design and implementation of initiatives suitable for reducing the generation of vibrations at the source (eg ensuring that the resonant frequencies for specific parts of the machine are not close to the excitation frequencies; appropriate choice of materials used in the construction; provide for insertion of additional masses or balancing of rotating parts);
  • must be foreseen integrated protection measures to prevent the transmission of vibrations to the whole body or to the hand-arm system (eg by introducing suitably designed springs or dampers);
  • finally, it is necessary that the user is clearly informed aboutresidual emission of vibrationsso that it can take appropriate measures “.

It is then stated that para. 2 i art. 1.5.9 states “a method of assessing the effectiveness of the measures taken to reduce the risk associated with the vibration emission based on the comparison of the risk level with that of similar machines (for purposes, morphology, power and speed) also from different manufacturers. The method consists in comparing the emission values ​​measured on the machine under test with those measured on a similar machine under the same test conditions “.

The Machinery Directive, the risk of vibration and the content of the manual

Other additional requirements regarding the risk of vibrations are then contained in various points in the directive and relate to e.g. preparation of instructions (1.7.4.2), portable hand-held and hand-held machines (2.2), mobile machines (3.6) and for the seats (1.1.8).

For example, we focus on some parts of point 1.7.4.2 (The content of the instructions) in Annex I:

Each instruction manual shall, where applicable, contain at least the following information: (…) (f) a description of the post or posts which may be filled by the operators; (…) (j) installation and installation instructions aimed at reducing the noise and vibration produced. “(…)

Therefore, the manufacturer is obliged to provide the machine with “instructions in the language of the country in which it is marketed or in the official languages ​​of the Community”. And among the elements that this manual must contain, “point (f) requires a ‘generic’ description of the workstations, which, however, also involves adjusting the seats, footrests or other parts of the machine that ensure good posture and reduce vibrations transmitted. In addition, point (j) requires installation and installation instructions to reduce vibrations which may relate, for example, to specifications of foundations with sufficient damping properties ”.

The goals of declaration of vibrations transmitted by the machine

The document then reports information on the contents of Point 2. (Additional essential health and safety requirements for certain categories of machinery) and part point 3. (Additional essential safety and health protection requirements to address the hazards due to the mobility of the machines) ofAnnex I..

It is stated that the first paragraph of section 2.2.1.1 (Instructions) and the first paragraph of paragraph 3.6.3.1 (Vibrations) “define physical amounts of transmitted vibrations from the mobile machine to the hand-arm system or the whole body to be declared in the instructions “:

  • “For handheld and handheld laptops (2.2.1.1) if the value measured on the machine is higher than 2.5 m / s2, it must be stated; if, on the other hand, the value measured on the machine does not exceed this value, the instructions must contain this information “;
  • “For mobile machines (3.6.3.1), the values ​​measured on the machine must be declared if they exceed 2.5 m / s2to the hand-arm system and 0.5 m / s2for the whole body. If the values ​​measured on the machine do not exceed these values, this must be stated in the instructions “.

It should be noted that for both requirements (clauses 2.2.1.1. And 3.6.3.1) the vibrations transmitted by the machine “must therefore be measured by the machine tool builder using an appropriate test method, unless it has been established that for the category of machinery in question the measured values ​​have never exceeded the above limit; in this case, this aspect may be specified in the type C standard relating to the relative category of machinery “.

Therefore declaration of vibrations transmitted by the machine serves two main purposes:

  • “Stores users in the choice of a machine that has a low emission of vibrations;
  • provide useful information to the employer during the risk assessment in accordance with the national provisions implementing Directive 2002/44 / EC on exposure of workers to the risks related to physical agents (vibrations) “.

Finally, it is reiterated that “the level of worker exposure to vibration can not only be deduced from the manufacturer’s declaration of vibration emission, as the operator’s exposure also depends on other factors”.

We conclude by referring to the full reading of the document, which also focuses on the need to specify the uncertainty associated with measuring vibrations and provides further information on the Machinery Directive, on Directive 2002/44 / EC and on technical standards.

RTM

Download the document from which the article was taken:

Inail, Department of Medicine, Epidemiology, Occupational and Environmental Hygiene, “Acoustic and vibrating certification of machines. Operating manual “, edited by Patrizio Fausti, Cristina Marescotti, Francesco Pompoli and Andrea Santoni (University of Ferrara – Department of Engineering), Eleonora Carletti and Francesca Pedrielli (Imamoter – Institute for Agricultural and Earth moving machinery – National Council of Research), Alessandro Peretti (School of Specialization in Occupational Medicine, University of Padua), Jacopo Griguolo (Technical Expert in Environmental Acoustics), Pietro Nataletti and Antonio Moschetto (Inail – Department of Medicine, Epidemiology, Occupational and Environmental Hygiene), manual prepared as part of Bric Inail ID26 project of Inail Research Activities Plan 2016 – 2018, Health and Safety Series, 2020 edition (PDF format, 5.37 MB).

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