Whole body vibration has not been researched as much as hand-arm vibration and there are no clear links between levels and duration of exposure to vibration and symptoms.
However, the HSE states that the main causes of exposure include:
- driving off-road vehicles too fast over rough ground;
- driving vehicles with poor suspension on badly paved surfaces;
- poor driving posture in large road-going vehicles; and
- poorly designed controls and visibility, making twisting and stretching necessary when driving.
HSE adds that employees most at risk from exposure to WBV include:
- operators of construction and quarry vehicles and machinery;
- operators of agricultural or forestry machinery;
- drivers of industrial trucks, e.g. forklifts;
- drivers of road haulage and rail vehicles and buses etc.; and
- operators of large compactors, hammer and/or punch machines, e.g. hammer mills and mobile crushers etc..
Guidance is available in the Guidance Whole-body Vibration, L141 and the leaflet INDG242 Control back-pain risks from whole body vibration.
Assessing the WBV risks
Remember, your risk assessment should not only focus on whole body vibration. Other ergonomic factors are likely to be far more important:
- poor design of controls, making it difficult for the driver to adjust and/or operate the machine or vehicle easily, or to achieve good visibility without twisting, leaning or stretching;
- incorrectly adjusted controls and seat, resulting in continual twisting, bending, leaning or stretching to operate the machine;
- sitting for long periods without being able to change position;
- poor driver posture while operating/driving mobile machines and vehicles;
- repeated manual handling of loads by the driver;
- repeated climbing into/jumping down from a high cab;
- survey ‘at-risk’ employees, asking a few simple questions relating back pain to exposure to WBV; and
- obtain information from vehicle/machinery manufacturers. They must inform you if WBV is a hazard when supplying new machinery.
HSE say that risk assessments for exposure to WBV should also consider those who are more sensitive to vibration risks. These include:
- pregnant workers and those who have recently given birth. You should not expose such workers to uncomfortable WBV, particularly where the abdomen is exposed to shocks and jolts;
- young people, who may be at greater risk of damage to the spine as muscle strength is still developing and their bones do not fully mature until around the age of 25. Regular exposure to shocks and jolts should therefore be limited;
- people with neck or back problems; and
- people who have recently undergone any form of surgery and people with internal or external prosthetic devices (not including dentures), who will also be susceptible to shocks and jolts.
Broadly speaking, you can assume the exposure action value will be exceeded if vehicles or machines are used off-road. Driving vehicles solely on-road is unlikely to result in the exposure action value being exceeded, unless the vehicles have poor suspension and they are driven for most of a working day or shift. In most cases where the evidence suggests that exposure is unlikely to exceed the exposure action value, it will be sufficient to record that fact.
Actions to reduce exposure to WBV
Whichever method you use to decide who is at risk, there are things you can do to reduce exposure to whole-body vibration:
- ensure that vehicles and machinery are adequately maintained, particularly suspension components;
- ensure the driver’s seat is in good repair, and gives good support;
- check whether a suspension seat is fitted suitable to the vibration characteristics of the machine and, if not, whether a suitable seat can be fitted. You may need to talk to the machine’s manufacturer about this;
- if a suspension seat is fitted, ensure it is correctly adjusted to the operator’s weight according to the manufacturer’s instructions (some seats adjust automatically in this respect);
- ensure that where equipment in vehicle cabs can be adjusted, it is set to suit the size and reach of the drivers expected to use it;
- choose the right vehicle or machine for the ground surface and task;
- check that vehicles have the right tyres and that they are inflated to the correct pressure for the ground surface;
- identify the vehicles or machines and work situations with the highest levels of vibration and arrange a rota for operators or drivers to reduce the time spent on them by individuals;
- plan work site routes with the smoothest terrain; and
- if possible, improve the ground surface over which vehicles have to be driven regularly, for example, by repairing pot-holes, clearing debris or levelling it out.