Document ID: chunk:federal_register_of_legislation:F2016L00426:reg:0:p5
Version: federal_register_of_legislation:F2016L00426
Segment Type: reg
Provision Reference: reg 0 (pt 5/20)
Character Range: 34822–37663

Using engineering controls
A good understanding of the operation of the plant or process is necessary when considering ways of minimising noise at its source.
Examples of engineering control measures include:

    * eliminating impacts between hard objects or surfaces
    * minimising the drop height of objects or the angle that they fall onto hard surfaces
    * using absorbent lining on surfaces to cushion the fall or impact of objects
    * fitting exhaust mufflers on internal combustion engines
    * fitting silencers to compressed air exhausts and blowing nozzles
    * isolating a vibrating noise source to separate it from the surface on which it is mounted using rubber mounts and flexible connections
    * ensuring gears mesh together better
    * fixing damping materials (such as rubber) or stiffening to panels to reduce vibration
    * fitting sound-absorbing materials to hard reflective surfaces
    * turning down volume controls
    * changing fan speeds or the speeds of particular components
    * changing the material the equipment or its parts are made of (change metal components to plastic components).
Further information on using engineering controls is at Appendix E.

5.4 Isolating the source of noise
Examples of isolating the source of noise from workers include:

    * building enclosures or sound proof covers around noise sources
    * using barriers or screens to block the direct path of sound
    * locating noise sources further away from workers (see Figure 1)
    * using remote controls to operate noisy plant from a distance.

Figure 1 Sound spreading in an open space away from reflecting surfaces and measured at a certain distance from the source is reduced by about 6 dB for each doubling of that distance. Sound is reduced less when spreading inside an enclosed space.

If a small sound source produces a sound level of 90 dB(A) at a distance of 1 metre, the sound level at  2 metres distance is 84 dB(A), and at 4 metres is 78 dB(A), etc.

Maintenance
Regular maintenance of plant and equipment is essential as it will deteriorate with age and can become noisier. Check for changes in noise levels – badly worn bearings and gears, poor lubrication, blunt blades, loose parts, unbalanced rotating parts and steam or air leaks all create noise that can be reduced with good maintenance. Engineering controls such as vibration mountings, impact absorbers, gaskets, seals, silencers, barriers and other equipment should be regularly inspected and maintained.

5.5 Using administrative controls
Administrative noise control measures reduce the amount of noise to which a person is exposed by reducing the time they are exposed to it. Examples include:
    * organising schedules so that noisy work is done when only a few workers are present
    * notifying workers and others in advance of