Smooth a path to silence01 December 2005
There shouldn't be any significant problems meeting the requirements of the new noise and vibration regulations, but there are issues which employers need to consider - and they should be wary of figures quoted by some equipment manufacturers. These were the key messages to come out of the SOE seminar entitled 'Noise and Vibration Legislation Uncovered', which was held in Birmingham recently.
There was general agreement at the gathering that manufacturers have a duty to make machines as quiet as possible and deliver minimal vibration to their users, but it is employers of labour and site managers who have the legal responsibility to ensure employees are not harmed or suffer excessive exposure to noise and vibration.
Tim Ward, a principal specialist inspector with the Health and Safety Executive, said the HSE "did not want to enforce exact numerical limits", but instead preferred to work to reduce overall risks to workers.
On the legal side, there was some concern as to whether an employer would be liable, if an employee whose hearing or health was already damaged came to them.
One questioner at the seminar commented, "it always seems to be the last employer who gets sued". Ian Toft, of Wake Smith Solicitors, agreed, while commenting that so far there had only been one such case, However, he added: "The thinking is that it is the last employer who bears responsibility."
He suggested employers should insist on access to medical records of prospective employees. He also pointed out that it was often the same insurers who were funding both sides of disputes and that, in future, there could possibly be an arrangement to cut out lawyers. He then mentioned that, to protect themselves and their employees, it was vital that employers "train their employees to always enter accidents in the accident book".
A delegate asked what instruments an employer should have: HSE's Ward replied that a Type 2 integrating sound level meter accurate to 1dB would be sufficient. The cost of such instruments is a few hundred pounds, but they can be hired far more cheaply. Measurements should be taken roughly at the operator ear positions.
Shaken up
Measuring hand-arm and whole body vibration is much more difficult, and not recommended for most companies. This leaves having to make risk assessments, based on available data obtained by experts. While data produced by independent laboratories should be reliable, there was some disagreement between HSE's Tim Ward, Peter Wilson, the director of the Industrial Noise and Vibration Centre, and Mark Ireland, senior engineer, engineering standards and legislation at JCB, as to how best to assess risk, if using data supplied by manufacturers. Ireland insisted that figures published by JCB are realistic and accurate, and based on work cycles. Ward cautioned that manufacturers' data in general, however, "may not relate to real use" and "may not represent your work".
Peter Wilson was rather dismissive of standard tests relating to hand arm vibration produced by tools. However, since the event he has said he would like to point out that whole body vibration tests undertaken by companies such as JCB "probably do reflect real work cycles". He added
that he was pushing for more realistic HAV tests, because manufacturers understandably did not wish to publish realistic data unless their competitors were forced to do so as well.
He was also insistent that anti-vibration gloves do not work - a point which nobody at the seminar disagreed with. Everyone was also in agreement that exposure times refer to those periods in which noise is being produced at full throttle, and to vibrations experienced when machines were actually doing something and hands were in firm contact with handles. Times when engines are idling, or operators are waiting for something to happen before they can engage in active work, should not count.
Wilson urged companies to set up tool registers based on reliable published field data, such as that maintained in his own company's 'HAV-Base' (a Hand-Arm Vibration database). He did single out a few companies for praise.
He praised a Worcester plant hire company for its policy of only purchasing low vibration plant for hire and providing customers with vibration data. The firm had just won a £1.5m contract with a major utility company, thanks to this policy. He further urged companies to consider employee vibration exposure when deciding how to carry out a task and cited the example of a demolition company which adopted use of remote-controlled demolition machines. As well as reducing vibration exposure to zero, this resulted in more work being done with fewer employees and reduced overall costs. "Our experience is that cheap, high vibration hand tools may cost less initially," he concluded, " but they don't usually last long and end up costing more overall."
All agreed on the importance of training operators to minimise risks to themselves. Peter Wilson proposed the acronym, MEASURES: Maintenance, Exercise hands during work periods, Always report any hand arm symptoms, don't Smoke, especially before using tools, Use the right tool for the job in the right way, Report faulty, ineffective or poorly maintained tools, Ensure you keep your hands warm, and take Short breaks.
Seat of the problem
On the subject of whole body vibration, Mark Ireland insisted, "the suspension seat is still the most efficient method of reducing the transmission of whole body vibration to the operator". He compared it with the standard iron tractor seats of a few decades ago and explained that seats have to be the prime method of reducing vibration, because vehicle suspension systems are designed to improve road stability, not to reduce vibration. Modern seats not only incorporate springs, dampers and all kinds of adjustments, but are specifically designed for particular machines. This is an important fact if seats are changed, which they apparently should be every five or six years. However, if the ride is made particularly comfortable, the main effect is that operators tend to work their machines harder until vibrations reach maximum tolerance levels.
In the general discussion, a member of the audience commented that one consequence of air-suspended seats in trucks is that drivers tend to go faster over rough roads. For those who have to drive on dirt roads, the effect of having comfortable seats and driving fast over 50mm x 50mm corrugations was that shock absorbers tend to fail much faster.
To reduce vibration damage to man (or woman) and machine, Ireland urged that operators should be encouraged to steer, brake, accelerate, shift gears and move and load attachment smoothly, and should adjust vehicle speed and travel path, avoiding bumps and potholes, to minimise vibration levels.
This had to be in addition to employer responsibilities to ensure seats are appropriate, seats and vehicles are maintained in good condition, and the site terrain over which machines have to travel is kept in good condition.
Key to best practice
Employers should insist on access to medical records of prospective employees to determine whether hearing or health was already damaged.
Companies should set up tool registers based on reliable published field data.
Employee vibration exposure should be considered when deciding how a task should be carried out.
Operators should be trained to minimise risks to themselves.
Type 2 integrating sound level meters accurate to 1dB can be hired relatively cheaply.
Industrial Noise and Vibration Centre
www.invc.co.uk
SOE
Related Websites
www.invc.co.uk
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