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Market Report: Health & Safety pt2: Hand arm vibration, noise & dust Real challenges Alan Guthrie updates the HAV situation and finds that, while progress is being made in some areas regarding standards of measurement, the need for information on ‘real-life’ vibration in other areas remains. First, let’s briefly recap. As EHN readers will know, the Control of Vibration at Work Regulations (CVWR) 2005 requires employers to recognise and control workers’ exposure to hand arm vibration (HAV) and impose a daily exposure action value (EAV). They also impose an exposure limit value (ELV), which comes into force in July 2007 where new machines are used, and in 2010 for all tools. However, as was highlighted by EHN’s first HAV Conference in October that year, hirers and contractors had concerns about the accuracy of tool vibration data on which risk assessment would be based. Existing standards for many powered hand tools generally provided single (dominant) axis readings, quoting the largest of the three axes of vibration, rather than a tri-axial (vector sum) figure derived from all three readings, which the CVWR required. In addition, as tests were undertaken under laboratory conditions and devised simply to enable comparisons between tools, doubts were expressed over whether they could represent real-life conditions. Indeed, many contractors, including those in the Major Contractors Group (MCG), have requested as a solution that manufacturers provide ‘real-life’ data in accordance with BS5349, a generic tri-axial standard for measuring and assessing HAV risks. To meet this demand, OPERC (the Off-highway Plant and Equipment Research Centre) at Loughborough University (www.operc.com) has developed test procedures designed to assess the performance and productivity of tools undertaking typical tasks, as well as the vibration level, and has published results on its on-line HAVTEC database. Standards for risk assessment Aware of the difficulties, the Health & Safety Executive (HSE) included HAV in its Supply Chain Initiative to reduce ill health in construction, with input from manufacturers, hirers and contractors, as it has similarly done with issues like kerb handling. In November 2005, the Construction Industry Working Group (CIWG) was formed to discuss ways forward among representatives from each sector. “The Group identified the most commonly used tools with the highest potential risk, and considered the reliability for risk assessment purposes of available standards,” states Dr David Smeatham, an HSE Specialist Inspector who sits on the CIWG. “These included petrol cut-off machines, compaction equipment, jigger picks and chipping hammers, breakers, demolition hammers, combi hammers, scabblers and needle scalers. We have considered whether the relevant standards were fit for the purpose of risk assessment, and what actions might be needed to make improvements.” The appropriate standards for different tool types (such as EN 60745 for electric power tools, EN ISO 19432 for petrol engined cut-off saws, and EN 8622 for pneumatic tools) have been developed to support the Supply of Machinery (Safety) Regulations 1992, which set out the Health & Safety requirements that equipment manufacturers, and others in the supply chain, are obliged to meet. They are harmonised for adoption throughout Europe and are the standards that enforcement agencies, such as the HSE in the UK, work with. “Standards committees are currently developing new standards that aim to provide reliable, reproducible tri-axial data and, importantly, to be sufficiently representative to enable a preliminary risk assessment of daily exposure to be carried out. This work has been done using a new ‘standard of standards’ (EN 20643), which sets out how these new standards should be written. We are now close to seeing many of these improved standards being formally adopted. “The standards aim to give a vibration figure representing the ‘upper quartile’ in use, also known as the 75th percentile. What this means is that, taking all intended uses of a tool ranging from the least arduous to the most demanding application, the result will theoretically reflect the 75th most demanding application. This is an accepted benchmark. As part of the supply chain, hirers are governed by the Supply of Machinery (Safety) Regulations, and if they provide manufacturers’ information on vibration that meets these Regulations, together with other required advice on correct operation, user safety and personal protective equipment for example, then they will have fulfilled their obligations (it should also be noted that, if equipment is sourced from outside the EU, suppliers must ensure the information is compliant with the Supply of Machinery (Safety) Regulations). Many hirers are also providing additional information to help end users manage the risk, which is great.” Appropriate controls However, there is another consideration. Under the CVWR, employers must assess workers’ vibration exposure and, if they are likely to be exposed above the daily exposure action value (EAV), appropriate controls must be implemented. Therefore, if someone uses a tool in a way that is likely to differ widely from the notional 75th percentile application, his employer – or perhaps the hirer who advises him – might seek more specific real-life data, such as that in OPERC’s database. As a separate article in this Market Report describes, many hirers are concerned that, despite the new standards, their depot staff will still be confronted by many variables to consider and more than one possible source of data. “If reliable ‘real-life’ data exists for a particular application, then obviously it could be used,” states David Smeatham. “There are a large number of tools, accessories, materials, operators and other variables that in theory could be assessed. The most important thing is that controls and risk management procedures are introduced to protect workers, such as considering ways of avoiding hand-held tool use, selecting and managing the use of tools where they are needed, providing training and, where necessary, conducting health surveillance. The new standards will enable more accurate assessments to determine whether those controls are needed.” HSE offers advice on HAV risk via its website (www.hse.gov.uk/vibration/hav). Kevin Minton, Hire Association Europe’s Technical Officer who sits on the CIWG, also believes the new standards should facilitate risk assessment for most applications, but that real-life data will also be needed for certain applications. HAE is currently examining ways in which both types of data might be incorporated in one database. “There are many variables concerning tool operation, like actual trigger time and operator technique, which can be overlooked if people get too preoccupied with vibration figures in isolation. A line has to be drawn somewhere regarding the required standards of accuracy. What is important is to obtain a figure that enables managers to estimate when controls are required. Ultimately, the aim is to provide data that is trusted and verifiable.” As we reported in our last issue, HAE (www.hae.org.uk) recently gave details of a proposed modified ‘traffic light’ system for indicating vibration levels of individual tools. Instead of labelling tools with only one of the three colours, the suggestion is to include more data, with the time taken to reach the exposure action value given in a green section, and the time to the exposure limit value in red. Other information, such as the points/15 minutes value as used in HSE’s exposure calculator and by some tool hirers, could also be accommodated, as well as the manufacturer’s declared figure. Ultimately, the key point is how much faith hirers and end users can place in the new standards for risk assessment purposes. Dr David Edwards, the Founder of OPERC, contends that “while the revised standards like EN 60745 are obviously an improvement by giving tri-axial data, the main issue is whether they can reflect contractors’ real-life usage. Paradoxically, while manufacturers seek replicability and the elimination of variability for purposes of comparison, real-life testing aims to measure that very variability.” Several power tool manufacturers that EHN spoke to expressed confidence in the new standards as a much more reliable source of vibration data covering a much wider range of applications. But EHN also understands that some contractors still remain to be convinced because they require a clearer indication of the productivity of equipment. Such data is important for tool selection, since it is possible that a machine with a higher vibration value might get a task done more quickly and expose the operator to a smaller overall vibration dosage than a product with a lower rating. The revised standards may be a step forward, but the need for real-life testing, to recognised and reliable standards, surely remains. • Executive Hire News › Archives › April 2007 › Market Report › Real challenges
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