A powered tool in the hand
September 03rd 2009 Removing danger to operators where possible is the key to health and safety when using air powered tools. Greg Bordiak, technical officer, BCAS looks at powered tools with regard to hand-arm-vibration (HAV) and noise.
As mad as a hatter or so the saying goes. A sad reflection of what you could expect if working in the hat business years ago. Removing the mercury from the process solved that problem. Mining, quarrying, stone masonry, ship building have used manual tools since these activities begun. Powered tools came to prominence when compressed air became available commercially in the 19 century. Along with the benefits of powered tools came the disadvantages of doing the work namely noise and vibration.
The perfect powered tool would be one that did the work without the attendant noise or vibration. A balance has to be struck between safety and productivity but having said that great advances have been made in the last 20 years in reducing the levels of noise and vibration that the powered tools themselves produce.
Controlling noise from both the powered tool and what is allowed in the working environment have moved ever lower. The Machines Directive both encourages the development of low noise and low vibration equipment and asks that the noise and vibration levels be identified in instructions. The Physical Agents (Vibration) (Noise) Directives seek to reduce the exposure of workers to both. The workers directive provides for action and limit values for both noise and vibration.
Manufacturers are provided with standards to measure both noise and vibration, these standards have recently been improved to provide results, especially for vibration, which reflect figures that can be expected in actual working conditions. What these figures for both noise and vibration do not give is a result that includes what is called exposure. Exposure is the noise or vibration experienced by the user of the powered tool in a working day. That working day according to the Physical Agents Directive is made up of 8 hours.
Having reduced noise and vibration to low levels, manufacturers are still looking at ways to lower them even more. There is however a common denominator here which is the operator of the powered tool who can greatly affect both the noise and the vibration. The operator can be provided with low noise and vibration powered tools with the added benefit of PPE which would all be for nothing if the operator is not trained in the use of the equipment or ignores the PPE.
Where built-in technology provides for low vibration of the powered tool this can be defeated if the sprung handles provided to reduce the effects of vibration are pushed beyond their working limits. As the old lady taking the medicine said it can't be doing me any good it tastes to nice! So it is with powered tools if they dont provide some sort of feedback to the operator then he thinks it's not doing its job.
Rock musicians and rock concert goers know that loud noises make them deaf. No one knows what the safe level is for vibration but the clear message is the lower the better.
The question has to be asked Is that low level the actual value given by the manufacturer or is it the time that the operator is exposed to a level of vibration? A factor in the answer is the relationship between what the manufacturer provides and how the operator makes use of the hand-held powered tool. They should not be seen as mutually exclusive. More articles from BCAS: | 
