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Exposure to mechanical vibrations is a fact of life for many workers in the construction and metalworking industries. As such, special preventive measures must be put in place to protect the health and safety of employees who are exposed.
What is a mechanical vibration?
What is the definition of a mechanical vibration?
Mechanical vibration is transmitted by the operation and use of a work tool. Depending on the work equipment used, these vibrations can reach thresholds that represent a health and safety (H&S) hazard for workers.
The French Labour Code distinguishes between two types of vibration(Article R4441-1 C.Trav.):
- vibrations transmitted to the hands and arms, which can lead to the risk of vascular disorders, osteoarticular lesions or neurological or muscular disorders;
- vibrations transmitted to the whole body, which can lead to lower back pain and microtrauma of the spinal column.
Exposure to mechanical vibrations is present in many sectors of activity (mainly construction, mechanical engineering and metallurgy) and thus raises a real occupational health and safety issue.
Examples: the use of a chainsaw by loggers, the use of a jackhammer or construction equipment by construction workers, the use of tools by workers in industrial sectors, or simply working near work equipment emitting strong vibrations.
What are the exposure thresholds for mechanical vibration?
Exposure to mechanical vibrations can be more or less significant, depending on the duration of exposure and the work tool used. The French Labor Code defines regulatory thresholds for situations where workers are exposed to significant and/or long-lasting vibrations.
These exposure thresholds are calculated over an eight-hour period (Article R4441-2 C.Trav.). These are known as daily exposure limit values (VLE).
This limit value for exposure to mechanical vibration is(Article R4443-1 C.Trav.) :
- 5 m/s2 for vibrations transmitted to hands and arms ;
- 1.15 m/s2 for whole-body vibrations.
Any situation or workstation exceeding these thresholds is prohibited and represents a real danger for workers.
📃 Documentation: you can find the method for calculating daily exposure to mechanical vibration on the the dedicated page of the Institut national de recherche et de sécurité (INRS) website..
In addition, specific preventive measures must be taken when the mechanical vibration exposure value exceeds(Article R4443-2 C.Trav.) :
- 2.5 m/s2 for vibrations transmitted to hands and arms ;
- 0.5 m/s2 for whole-body vibrations.
These values are also known as action values (AV).
⚠️ Warning: it is forbidden to assign young workers to work exposing them to vibration levels exceeding the action values (Article D4153-20 C.Trav.).
What are the regulatory obligations concerning the prevention of risks linked to mechanical vibrations?
Prevention of the risk of exposure to mechanical vibration is based on the general principles of prevention(Article R4442-2 C.Trav.). Accordingly, the employer must take measures to eliminate or minimize exposure to mechanical vibration (Article R4442-1 C.Trav.).
Given the particular risks associated with exposure to mechanical vibrations, the assessment of occupational risks must comply with a specific procedure that takes into account at least(Article R4444-5 C.Trav.) :
- level, type and duration of exposure, including exposure to intermittent vibrations or repeated shocks;
- daily exposure limit values (ELVs) and action value thresholds (AVs );
- profiles of exposed workers, particularly pregnant women and young workers under the age of 18;
- the impact of vibration on safety and work performance;
- Vibration information supplied by work equipment manufacturers;
- the use of work equipment to reduce mechanical vibrations ;
- cumulative risk factors in the case of special working conditions (such as low temperatures);
- advice from the occupational health and safety department.
🔎 Focus: with the help of the occupational physician, the employer must adapt prevention measures to the needs of workers at risk from exposure to vibration (Article R4445-5 C.Trav.)
As a reminder, the assessment of the risks of exposure to mechanical vibrations must be recorded in the " document unique d'évaluation des risques professionnels"(Article L4121-3-1 C.Trav.).
If the risk assessment reveals that certain workers are exposed to vibration, the employer must measure their levels of exposure to mechanical vibration. These measurements are used to determine whether regulatory thresholds have been exceeded(Article R4444-1 C.Trav.).
These measurements must be carried out by competent persons, with the assistance of the occupational health and safety department if necessary(Article R4444-2 C.Trav.). In addition, the results must be kept for 10 years, and made available to the CSE (social and economic committee), the occupational physician and the labor inspectorate(Article R4444-3 C.Trav. and Article R4444-4 C.Trav.).
⚠️ Warning : the labor inspectorate may ask the employer to have measurements of exposure to mechanical vibrations carried out by an accredited body (Article R4722-18 C.Trav.).
Please note that since October1, 2017, the professional prevention account (C2P) no longer takes into account the occupational risk factor linked to mechanical vibrations. It therefore no longer allows employees to accumulate points in connection with their exposure.
However, this occupational risk factor is taken into account in the following two cases:
- for an employee recognized as suffering from an occupational disease and with a permanent disability of at least 10%: entitlement to early retirement;
- for an employee recognized as suffering from an occupational disease but who has not reached a permanent disability of 10%: with the employer's agreement, it is possible to work part-time, up to a limit of 50%, 2 years before retirement.
How to reduce exposure to mechanical vibration?
Prevention actions
When the regulatory threshold is exceeded, the employer must implement an action plan to reduce mechanical vibrations, in particular by means of the following measures(Article R4445-2 C.Trav.):
● use of work processes that reduce or limit the duration and intensity of exposure to mechanical vibration;
● use of appropriate work equipment producing as little vibration as possible ;
● use of equipment that effectively attenuates transmitted vibrations;
● maintenance of work equipment and workplace ;
● modification and layout of workplaces and workstations ;
● adequate information and training for workers ;
● limiting the duration and intensity of exposure ;
● organization of working hours and rest periods.
🔎 Focus : The protective equipment used must be so effective as to reduce vibrations to below threshold levels (Article R4445-3 C.Trav.).
Training
Training is an effective way of preventing occupational hazards. Proper use of work equipment limits the risks of mishandling and ensures optimal use.
Workers exposed to the risk of vibration must be trained and informed about(Article R4447-1 C.Trav.) :
- techniques and work practices for minimizing risks due to exposure to mechanical vibration;
- measures taken to eliminate or minimize mechanical vibrations;
- the vibration thresholds to which they are exposed;
- regulations concerning maximum exposure to vibrations ;
- illnesses and injuries caused by the use of vibration-producing work equipment, and their symptoms;
- individual monitoring of their state of health.
Medical follow-up
Workers exposed to mechanical vibrations are subject to medical monitoring which includes an information and prevention visit (VIP) carried out by a health professional, and a periodic visit depending on working conditions, the worker's state of health and age, and the occupational hazards to which he or she is exposed.
⚠️ Please note: the VIP must be carried out within three months of the employee taking up his or her new post (Article L4624-1 C.Trav.).
VIP plays a dual role: on the one hand, it informs workers of the risks to which they are exposed in the course of their work, and on the other, it verifies their suitability for the job in the light of these risks.
Workers may also request a medical examination if they feel the need to do so because of their state of health or working conditions.
By monitoring workers' state of health, the occupational physician analyzes and controls the risks to which employees are exposed. For this reason, the occupational physician must inform the employer if he/she observes a deterioration in the state of health of workers.
The employer must then draw the appropriate conclusions from the occupational physician's opinion, and may be required to review the risk assessment and preventive measures in place (Article R4446-3 C.Trav.).
Conclusion
Exposure to mechanical vibration is an occupational risk factor requiring specific preventive measures. Depending on the degree of employee exposure, additional preventive measures are required. Over and above risk prevention, mechanical vibrations can cause real discomfort, and eliminating or reducing them also has a positive impact on employee well-being.