The BGs report: Low-noise circular saws protect hearing and reduce costs

25.04.2006

Noise at levels harmful to the hearing during work with circular saws can be avoided effectively and cost-efficiently. This has been shown by a study conducted by the BG Institute for Occupational Safety and Health (BGIA). "Special low-noise saw blades reduce the noise exposure in many cases to a value which is not harmful to the hearing," explains Dr. Martin Liedtke, expert for noise at the BGIA, "and not only that, they are also economical." The blades with damping vibrate less in use and therefore wear up to 50% less quickly. At the same time, the low-vibration properties permit more precise cuts and therefore a higher standard of work.

Noise is one of the most common occupational health hazards. The noise level from circular saws is virtually always at or above the permissible noise limit value of 85 dB(A), which marks the threshold for a hazard to health. Even when wood is being sawn, the noise level may reach 90 dB(A). During plastic or metal cutting, it is close to 100 dB(A). Noise exposure is frequently a problem in day-to-day activity. "Circular saws are found all over the place," says Liedtke. "The BG for the woodworking sector alone currently has over 53,000 member companies, which virtually without exception all have at least one circular saw. Circular saws are also a typical tool in the metal and plastics processing sector and in construction."

Low-noise sawblades have been available for many years, but have seldom been used in practice. However, they reduce the noise exposure of human hearing considerably, as was demonstrated objectively by the BGIA's study on 29 standard commercial low-noise saw blades: the noise level falls by up to 7 dB(A) during sawing of wooden boards, and by almost 12 dB(A) during sawing of squared hardwood timber. For aluminium and plastics, the noise level is reduced by 6 dB(A) and 11 dB(A) respectively. Liedtke: "These are huge drops. A drop of just three decibels already halves the acoustic energy. A drop in noise of ten decibels is perceived by the human ear as being only half as loud." If the measure is able to reduce the noise level at the workplace to below 85 dB(A), the employer can dispense with expensive noise-reduction arrangements and the marking of high-noise areas. The wearing of hearing protection ceases to be compulsory for employees. At the same time, the service life of the saw blades and the cut quality are improved. "These are all benefits to the business, which more than compensate for the approximately 30% higher purchase price of the saw blades," concludes Liedtke.

The blades studied were sourced from 15 manufacturers. They were selected on the basis of a comprehensive market survey. The list can be downloaded.

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List (PDF, 42 kB) of manufacturers of noise reduced saw blades (excerpt of BGI 5051, in German)