Vibration machines and certification: seat requirements and standards

& horbar; An inail document on acoustic and vibration certification of machines contains useful information on the requirements for the seats, on European legislation and on the technical standards for vibration.

Section 1.1.8 of Annex I to the Machinery Directive deals with a specific aspect of the interface between the operator and the machine which can cause discomfort, fatigue and damage to health due to incorrect construction. Let’s talk about the seats and the recommendations contained in the legislation regarding vibrations and ergonomics associated with the operator.

That first part requires that the machine be designed in such a way that it is possible to install seats. So manufacturers need to consider when designing a machine whether operators could be more comfortable and perform all or part of their tasks more comfortably and efficiently seated. This means that special attention must be paid to the height of the work surfaces, the location and shape of the controls and other parts of the machine to which the operator must have access, as well as the space in which to place. the seat and the maneuver of the driver’s upper and lower limbs.

That according to and third paragraph then define in seating requirements.

The seat “it must be designed in such a way that the operator can maintain a stable position taking into account predictable conditions of use, including in particular predictable movements of the machine. The relevant parameters for the seat itself, such as the height, width, depth and inclination of the seat, the position of the backrest and any armrests and footrests must be adjustable to take into account the variation of the physical dimensions of the operators. It must be possible adjust the position of the seat in relation to that of the controls, including the pedal operated by the operator, by equipping the position of the seat, the controls or both with an adjusting device. For machines where the seated operator can be exposed to vibrations due to the operation of the machine itself or the movement of the machine over uneven terrain, one way to reduce the risk of exposure to mechanical vibrations transmitted to the whole body is to equip the seat with a suitable suspension system“.

The Vibration Directive

The document also focuses on Directive 2002/44 / EC of 25 June 2002 on the minimum health and safety requirements for exposure of workers to the risks arising from physical agents (vibrations).

More specifically, the Directive:

  • establishes in exposure limit values and action values;
  • specifies obligations of employers in connection with the determination and assessment of risks;
  • establishes measures to be taken to reduce or avoid exposure
  • explains in detail procedures to provide workers with proper information and training“.

In addition, the directive “Requires EU Member States to implement an appropriate control system the health of workers exposed to vibrational hazards “.

Vibration certification and technical regulations

The inail document states that “terms and definitions regarding mechanical vibrations and shocks are defined in the standard UNI 9513: 1989prepared in accordance with the draft standard ISO / DIS 2041: 1986draft standard ISO 2041: 1990now replaced by ISO 2041: 2018Mechanical vibration, shock and condition monitoring – Vocabulary“.

In legislation, they are different “vibrations transmitted to the hand-arm system (HAV) and vibrations transmitted to the whole body (WBV)“.
Almost always “the measurement of the vibration acceleration transmitted to the hand-arm system (HAV) is performed in accordance with what is described by the standards UNI EN ISO 5349-1: 2004 And UNI EN ISO 5349-2: 2015“.

There measurement of vibration acceleration transmitted to the whole body (WBV) ”is usually performed in accordance with the standard UNI ISO 2631-1: 2014 Mechanical vibration and shock – Assessment of human exposure to whole-body vibrations – Part 1: General requirements“Which” defines the methods for measuring periodic, random, and transient vibrations transmitted to the entire body.

The document then reports information about the standard UNI ISO 2631-5: 2019 Mechanical vibrations and shocks – Assessment of human exposure to whole-body vibrations – Part 5: Method for assessing impulsive vibrationson the norm UNI CEN / TR 15172: 2008 Whole Body Vibration – Vibration Risk Reduction Guidelines – Part 1: Engineering Design Method for Machine Design and on the norm UNI EN 12096: 1999: Statement of vibrator emission values.

Also with the norm UNI EN 12096The standards UNI EN 1032: 2009: Mechanical vibration – Examination of mobile machines in order to determine vibration emission values it is considered as “the basic standard for evaluating the vibration emission of mobile machines transmitted to the whole body or to the hand-arm system. The purpose of the standard is that the procedures laid down by the various technical standardization committees for the different families of machines:

  • is as much as possible homogeneous and in accordance with general standards for measuring the vibration emission;
  • supply to manufacturers a normalized method to determine and declare the emission values ​​of their machines;
  • refer to the most recent techniques and methods for measuring emissions vibrating;
  • allow the user or inspection bodies to compare the emission values ​​for different machines and check the emission values ​​specified by the manufacturer.

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