Overview

Whole-body vibration is vibration from machines and/or vehicles that moves into the worker’s body through the buttocks, back or feet.

This includes:

  • seated and standing workers who drive vehicles or mobile equipment
  • workers who are involved in operations in which machinery vibrates, such as vibratory separators

Health risks

Workers are at greatest risk of health effects from whole-body vibration when:

  • the vibration has a high magnitude (level)
  • there are long, frequent and regular exposures
  • the vibration exposure has a dominant frequency below 20 Hz
  • there are severe shocks or jolts in the vibrations

The amount of vibration that travels through the body can differ based on body posture and the dominant frequency of vibration. As a result, the affected organs/tissues can differ and the effects of exposure can be complex.

Exposure may cause discomfort, affect performance, aggravate pre-existing back injuries and cause motion sickness.

Studies have shown strong evidence that long-term exposure can result in increased risk of disorders to the lumbar spine (such as low back pain, herniated disc and early degeneration of the spine), neck and shoulders.

There is some evidence that long-term exposure can result in:

  • effects on the digestive system
  • effects on female reproductive organs
  • effects on peripheral veins, such as varicose veins and hemorrhoids (in combination with long-term sitting)

Generally, it takes several years for health changes to occur due to whole-body vibration. Low back pain and disorders in the shoulders, neck and back may be due in part to vibration but can develop based on other ergonomics factors as well.

Equipment that causes whole-body vibration

Exposure to whole-body vibration can be found in work tasks such as:

  • driving vehicles in the construction and mining sectors
  • operation of transportation vehicles including buses, taxis, boats, long-haul transports and helicopters
  • driving forklifts over rough terrain or uneven surfaces such as loading dock plates
  • standing on surfaces that vibrate, such as concrete crushers, drill platforms and vibratory separators

Commonly used vehicles or mobile equipment where whole-body vibration may be a concern include but are not limited to:

  • forklifts
  • backhoes
  • bulldozers
  • dump trucks
  • tractors
  • asphalt pavers
  • graders
  • load, haul, dump machines

Legal requirements

The following outlines the legal requirements under the Occupational Health and Safety Act regarding whole body vibration.

Limit exposure to whole-body vibration

Employers have a duty under clause 25(2)(h) of the Occupational Health and Safety Act to take every precaution reasonable in the circumstances for the protection of a worker. This includes the protection of workers from exposure to whole-body vibration.

We look to the exposure limits for whole-body vibration as recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) to determine if a worker is at an increased risk of injury. The following is a summary of those recommendations from the ACGIH (2018).

Workers should not be exposed to a frequency-weighted root-mean-square daily (8 hours) vibration exposure above 0.87 m/s2 (meters per second squared, a standard unit of measurement). A daily vibration exposure of 0.87 m/s2 is believed to be the maximum value that a majority of operators or occupants may be exposed to with a low probability of health risks.

Workplaces should consider putting controls in place when daily exposure to whole-body vibration reaches 0.43 m/s2. Values between 0.43 m/s2 and 0.87 m/s2 for daily vibration exposure have a potential for health risks.

The above values are valid when crest factors are below or equal to 9. Crest factor is the ratio of weighted peak acceleration to weighted root-mean-square acceleration.

If crest factors are above 9, the vibration dose value should be used instead of the daily vibration exposure value. Vibration dose value is an alternate measure of vibration exposure that gives a better indication of the risks from vibrations that include shocks.

Workers should not be exposed to a vibration dose value above 17.0 m/s1.75 (meters per second to the power 1.75) in order to avoid health risks. Workplaces should consider putting controls in place when the vibration dose value reaches 8.5 m/s1.75.

If measuring and assessing whole-body vibration, worker exposure should be assessed or measured based on the following following International Organization for Standardization (ISO) Standards:

Risk assessments

A whole-body vibration risk assessment conducted by a competent person will allow the workplace to determine whether or not a worker is at an increased risk of health effects.

The assessment will also allow the workplace to make informed decisions regarding the measures that are required to prevent or control the health risks associated with whole-body vibration exposure.

The risk assessment should:

  • identify if whole-body vibration exposure may be causing or contributing to a health and safety risk
  • estimate whole-body vibration exposure to workers and compare them to recommended limits
  • identify controls
  • identify steps to control and monitor risk

Exposure to vibration is determined by two factors: the amount of time a worker is exposed to vibration and the frequency-weighted root mean square magnitude of vibration.

The European Union’s vibration publication:

  • contains a guide to good practices about whole-body vibration
  • discusses how to determine exposure duration and magnitude
  • shows sample vibration magnitudes of some common vehicles that expose workers to whole-body vibration

These sample vibration magnitude values, or values obtained from the manufacturer, can be used, along with the United Kingdom’s Health and Safety Executive’s “Whole body vibration calculator”, to estimate a worker’s level of exposure. Exposure to whole-body vibration can also be estimated using validated smart phone apps.

These methods help to determine if an in-depth risk assessment by a person knowledgeable in measuring vibration is needed.

Note: Daily exposure limits recommended by the ACGIH differ slightly from limits suggested in ISO 2631-1, the European Union’s vibration publication, and the United Kingdom’s Health and Safety Executive’s “Whole body vibration calculator” (which is based on the European’s Union vibration publication).

Vibration is just one ergonomics factor that may contribute to back pain. Others include:

  • poor posture while driving or operating machinery
  • sitting for long periods without being able to change positions
  • having controls in positions which require the operator to stretch or twist
  • not being able to properly see the task which results in an operator stretching or twisting  to get an adequate view
  • performing manual lifting, lowering and carrying of items
  • climbing repeatedly into or jumping out of a high or difficult-to-access cab

While all of the above factors on their own can result in back pain, the risk is increased when a worker is exposed to more than one factor while also being exposed to whole-body vibration. All of these factors should be considered when performing a risk assessment.

Preventing injuries

Controls are available to reduce or eliminate exposure to whole-body vibration. When there is exposure in the workplace, measures must be taken to control exposure and prevent injury.

The selection of appropriate workplace controls will vary, depending on the type of exposure and other factors. Some measures may include the following.

Elimination

The most effective method of preventing exposure to vibration is to remove the source of the vibration or remove the worker from exposure to the vibration.

Examples include mechanisation or automation of tasks, remote operation of equipment, separating the vibrating machinery from the work area where the operator is standing/sitting or redesigning the task so that vibrating equipment is not used.

Engineering controls

  • Purchase vehicles and equipment with lower manufacturer-reported vibration emission values.
  • Keep surfaces on which equipment is operated in good condition (level surfaces, no potholes, maintain roadways, etc.).
  • Provide a suitable seat for the vehicle (for example, passive or active suspension seat). Note: Suspension seats can increase the amount of vibration transmitted to the operator and are not always appropriate. Seat performance should be evaluated to ensure its effectiveness in reducing vibration exposure.
  • Select tires that are appropriate for the terrain being travelled on and ensure they are properly inflated.
  • Maintain the vehicle, mobile equipment or machinery so that it is in good condition.
  • Use vehicles or mobile equipment that have cab layouts and controls arranged so that the operator can maintain an upright, neutral posture that does not require the operator to have an extended reach or twist.
  • Dampen or isolate the source of the vibration or the work surface.

Administrative controls

  • Reduce the exposure to vibration by providing alternate tasks for the worker to perform in addition to work with vibrating vehicles and mobile equipment or machinery.
  • If the work requires driving for long periods, instruct drivers to take periodic breaks to leave the vehicle and stretch.
  • Have a regular maintenance schedule for vehicle, mobile equipment or vibrating machinery.
  • Minimize the distance travelled in a vehicle or mobile equipment.
  • Reduce vehicle/mobile equipment speed.
  • Provide training and information to workers and supervisors regarding whole-body vibration, including:
    • health effects
    • how to detect and report signs of injury
    • potential sources of exposure
    • ways to decrease exposure, including safe work practices and the use and adjustment of any devices that are provided to reduce exposure (for example, suspension seats).

Personal protective equipment

There is no effective personal protective equipment for reducing exposure to whole-body vibration.

Contact us

If you need more information about safety requirements, please contact the Ministry of Labour Health & Safety Contact Centre at 1-877-202-0008 on Monday to Friday, from 8:30 a.m. to 5:00 p.m., or webohs@ontario.ca.

This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations, and should not be used as or considered legal advice. Health and safety inspectors apply the law based on the facts in the workplace.

Updated: June 22, 2021
Published: January 15, 2019