Noise in agriculture
Noise from agricultural tools and machinery can cause permanent hearing loss and tinnitus. Repeated exposure to noise will lead to permanent damage. The damage can occur gradually over a number of years and remain unnoticed until it is too late. Noise does not have to be painful to be doing damage.
Typical noises in agriculture that can damage hearing include:
- tractor 95-100 dB(A);
- header 88-90 dB(A);
- orchard sprayer 85-100 dB(A);
- angle grinder 95-105 dB(A);
- bench grinder 90-95 dB(A);
- chainsaw 105-120 dB(A);
- pig shed at feed time 95-105 dB(A); and
- shotgun over 140 dB(C).
Most modern tractors are now fitted with sound-reducing cabs so the levels are likely to be below 80 dB(A). In older cabs and tractors with roll bars, levels may be as high as 95-100 dB(A). Remember that how much noise the operator is exposed to will also depend on the equipment the tractor is using.
- Keep doors and windows closed to achieve the lowest noise levels.
- Use the opening provided on many tractor cabs for routing cable and electrical controls rather than leaving the rear window open.
- Tractors operating near to maximum power or with other mounted or towed machinery may generate higher noise levels, particularly when using powered equipment such as forage harvesters, mowers, vacuum tankers, straw choppers and balers.
- Non-powered (towed) work equipment can be noisy.
- Don’t forget to take account of noise levels when working with tractor-powered stationary equipment such as portable grain dryers, grain blowers and saw benches.
Some of the noisiest working environments are found where woodworking machines are used. Noise levels can vary widely from machine to machine depending on conditions of use. Circular saws and band re-saws are likely to operate at 100 dB(A).
- Look for low-noise features when buying machinery. Always ask suppliers about noise levels.
- Wood chippers can be very noisy (up to 120 dB(A)) when processing timber waste or cuttings.
- Woodworking machinery such as circular saws, bandsaws and planers need to be properly maintained. A well-maintained band re-saw may have a 10 dB difference between idling and cutting noise levels, but a poorly maintained machine may show hardly any difference.
- Cutter sharpness is important as dull knives and worn blades and bands exert more force on the timber and so make more noise.
- Out-of-balance tools create vibration, reduce cutting efficiency and increase noise levels.
- Don’t forget to assess the noise from hand-held equipment such as brush cutters.
Always wear hearing protectors when operating a chainsaw. Noise levels measured at the operator’s ear can be as high as 110 dB(A) and so a very high level of protection is required.
- Don’t forget anyone working nearby may also need protection.
- Chainsaws should carry a prominent warning sign to remind users of the hazard.
- Make sure the silencer is in good working order.
Shed and process machinery
Machinery such as milling and mixing plant, grain drying (up to 95 dB(A)) and transportation equipment is very noisy. Running it inside buildings can make the problem worse and intensify the noise. If possible reduce the noise at source, but if this cannot be done then use the following controls.
- Prevent noise being transmitted by using acoustic enclosures, screens and sound-insulating panels.
- Fit controls in separate rooms or away from the noise.
- Fit silencers on exhaust systems.
- Eliminate the need for operators to be present with the equipment running, eg by rearranging the work so that no one needs to be in the noisy area, or restricting the time workers are exposed to the noise.
- Ensure machinery is properly maintained as worn parts, poor lubrication and loose panels may increase noise.
Large numbers of pigs in a building can create noise levels of 100 dB(A) or above, especially at feeding time. So even short-term exposure can be harmful, particularly if workers are exposed to other sources of noise during the day.
- Use mechanical or automated feeding systems to reduce the need to enter the building when it is noisiest, eg at feeding time.
- Make sure any work requiring entry is done during quieter periods.
- Fit the controls for the feed system away from the noise or in a protected area.
- Make sure you buy or hire low-noise tools and machinery so that you do not have to apply noise controls to noisy machinery afterwards.
- Mufflers or silencers can reduce noise transmitted along pipes or ducts, eg fit exhaust and intake silencers on internal combustion engines.
- Direct exhaust emissions well away from workers, eg by fitting a flexible hose to discharge several metres away from them.
- Place movable acoustic screens between the source of the noise and workers elsewhere in the workshop, eg when using abrasive wheels or portable grinders. Cover the screen with noise-absorbing material on the side facing the noise source to reduce the amount of noise reflected back into the area where the work is carried out.
- Increase the distance between the source of the noise and workers, eg by locating air compressors in separate rooms.
- Carry out quiet inspection tasks away from noisy repair areas.
Guns produce pulses of noise that can damage hearing immediately. Even people who only use guns occasionally may suffer permanent hearing damage. For clay pigeon shooting, it is important that shooters and trap operators wear suitable hearing protectors because of the prolonged and repetitive nature of the shooting.
Reducing the noise at source
The most effective and acceptable way to reduce noise in the workplace is to change the noise source (such as a machine) so that it makes less noise. This may mean using a quieter process instead of a noisy one (such as pressing rather than hammering), reducing the amount of metal to metal impact, treating radiating panels or using vibration isolation mountings. Regular maintenance is also important.
Some processes, such as metal and stone cutting and grinding produce very high noise levels. Noise reduced saw blades and clamping the work piece can help reduce noise levels but hearing protectors may still be needed.
If the noise cannot be sufficiently reduced at source then try to stop it from reaching people. This may be done by moving the item further away, by enclosing it or partitioning it off from quieter areas, by using sound-absorbing materials to reduce the build-up of noise or by using silencers.