David Wilson, Group Health, Safety, Environment & Quality Manager for HSS Hire, discusses the importance of maintaining tool appendages in the fight against Hand Arm Vibration Syndrome-related illnesses.
We all know that prolonged exposure to vibrating equipment can lead to a number of short and long-term illnesses, the most common being 'White Finger'. The term 'HAVS' comprises a number of conditions including carpal tunnel syndrome, or may manifest itself in loss of strength in the hands, inability to grip or numbness in the fingers (especially in the tips). According to HSE figures, up to 5 million UK workers are suffering from this illness and we must all act to reduce this number.
But what does this have to do with tool appendage maintenance? In short, all risk assessments covering Exposure Action Value (EAV) – currently set at 2.5m/s2 over an 8 hour working day – and Exposure Limit Value (ELV) calculations are less valid if the user is using old and worn out appendages (such as chisels, drill bits or blades). This is because blunt tools get hotter in the core and stresses can lead to cracking in the tool. Furthermore, poorly maintained appendages can increase the reverberations from powered equipment, increasing the levels of vibration exposure absorbed by the worker, plus it takes longer to do the job with blunt tools.
When calculating vibration output, users must identify the vector sum (tri-axel measurements) for tools on the market with different appendages, in typical site based materials. This can be done by accessing actual working figures from reliable databases, such as the Industrial Noise and Vibration Centre (INVC) Database or the Off Highway Plant and Equipment Research Centre (OPERC), which give accurate figures for almost all tools.
Starting with good tools that are sharp and appropriate for the job in hand is crucial, as is using appendages that have been correctly hardened and tempered plus correctly shaped for maximum efficiency. For drill bits, make sure that they are diamond / carbide tipped and when using saws, good quality cutting discs must always be used. Keeping tools sharp is equally important so that the EAV remains as accurate as possible throughout the life of the tool, not just at the start. The answer is to ensure that an effective tool maintenance programme is undertaken – either in-house (if the equipment is wholly owned) or, if renting equipment, by choosing a reliable channel partner who provides 'as new' equipment each time.
At HSS, we partner with Arrow Tools who re-forge, harden and temper our tool bits and appendages every time they are “off hired” and returned to store. For equipment on long-term hire, we'll either service it during the duration of the contract or provide additional kit to make sure the tools always work at optimum levels.