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Manual tasks and noise

Manual tasks are carried out in most types of rural work.

They include activities that require someone to exert force in order to:

  • grasp
  • manipulate
  • strike
  • throw
  • carry
  • move (lift, lower, push, pull)
  • hold or restrain an object, load or body part.

Manual tasks cover a wide range of activities, such as lifting chemical drums, bags of fertiliser, handling animals or packing on a processing line.

Manual tasks can contribute to injuries affecting all parts of the body, particularly the back, shoulder and wrist. These are commonly called musculoskeletal disorders.

More information is available on hazardous manual tasks including controlling risk factors and preventing injuries.


Part 4.1 of the Work Health and Safety Regulation 2011 requires all employers or self-employed people in the agriculture, forestry and fisheries industry to protect themselves and their workers from the risk of exposure to excessive noise.

Excessive noise

Noise creates sound pressure that is measured in decibels (dB). The 'A' weighting scale closely represents how the human ear perceives different frequencies of sound. The 'C' weighting scale represents the sensitivity of the ear at very high noise levels.

Under the regulation, noise is excessive where it exceeds the exposure standard of 85 dB(A), over an average of an eight hour period or where a peak noise level of 140 dB (C) occurs.

Maximum noise limits are reached by either a period of extended noise, such as operating machinery, or by a sudden extreme noise, such as firing a firearm or bashing on metal with a sledgehammer.

Every time the noise level increases by 3 dB, the exposure time must be halved. For example, 85 dB(A) over eight hours has the same exposure effect as 88 dB(A) over four hours.

Likely upper noise levels from different farming machinery and operations and the respective allowable exposure times without hearing protection are shown in the table below.

Typical noise levels from farming machinery and operations

Levels dB(A)Farming machinery or operationMaximum time
80 Tractor idling No limit
85 Working in a tractor with an enclosed cab 8 hours
90 Shearing shed 2 hrs 30 min
90 Chainsaw idling 2 hrs 30 min
95 Angle grinder 48 min
95 Grain auger 48 min
95 Header 48 min
100 Tractor operating under load without a cab 15 min
100 Orchard sprayer 15 min
105 Pig shed at feeding time 4 ½ min
120 Chainsaw cutting 8 seconds
140 Aircraft at 15m No safe exposure
140dB(C) Shotguns/rifles and other firearms far exceed the 140dB limit No safe limit: Instantaneous damage

Reducing noise exposure

  • Buy quieter machinery and equipment
  • Limit the amount of time spent in a noisy environment
  • Alternate noisy jobs with quieter ones
  • Keep machinery well maintained to reduce rattles and vibrations
  • Keep mufflers in good condition in accordance with the manufacturer's specification or install high efficiency mufflers
  • Apply vibration-reducing mats under stationary machinery and stiffening plates to vibrating surfaces
  • Fit sound absorbent materials to walls and ceilings of noisy workshops
  • Rearrange workshops so noisy tools are located towards the front or opening of the shed to disperse the noise outside
  • Wear suitable hearing protection where permanent or administrative controls are not effective options

Using hearing protection

Hearing protection is one way of reducing noise exposure if other means do not adequately reduce noise levels.

Hearing protection only works if worn correctly and used for the full period of exposure. Hearing protection should be used when:

  • firearms are used –the hearing protection should have a suitable class or SLC80 rating (as described below)
  • operating noisy equipment –ensure earplugs or muffs are kept near noisy equipment, to remind those operating the machinery to wear it. For example, place them in a tractor cab, near a chainsaw or rifle and display signs near equipment. If accessing hearing protection near machinery that is in operation, take into consideration the noise levels.

Selecting hearing protection

  • Ensure hearing protection is comfortable, effective and suitable for the job.
  • Always try earmuffs before buying to ensure they are comfortable and that the seal around the ear is adequate.
  • Hearing protection must meet AS/NZS 1270 (2002, Acoustics-hearing protectors) and be suitable for the work being done. The effect of a hearing protector should be similar to cupping your hands tightly over your ears.
  • General purpose earmuffs for the farm will have a Class 3 or 4 rating, or an SLC80 rating between 18 and 25 dB. The 'SLC80' figure stands for Sound Level Conversion valid for 80% of wearers, and indicates the noise level reduction in decibels expected when the protectors are worn correctly.
  • For some farm equipment and firing firearms, hearing protectors with a Class 5 rating or SLC80 of 30 or greater are required to provide protection.
  • Suppliers and manufacturers should be able to provide information on the most suitable hearing protection for the equipment used and tasks undertaken.

Maintaining hearing protection

  • Earmuffs and reusable earplugs should be cleaned with lukewarm soapy water, dried and stored in an airtight container when not in use, for personal hygiene reasons.
  • Damaged or defective protectors will not give full protection.
  • Read instructions carefully on how to insert earplugs and wear all hearing protection in accordance with the manufacturer's advice. Disposable earplugs should not be reused.

Learn more about noise.