Hazards and risks

Workers who operate or maintain unguarded or inadequately guarded machinery and equipment are at risk of minor abrasions, burns or cuts, and in more severe cases, injuries such as serious lacerations, crush injuries, fractures, amputations and fatalities.

Common hazards arise from:

  • nip/trap points
  • being drawn into rotating parts
  • crushing or shearing points
  • cutting components
  • noise
  • heat
  • sparks
  • flying debris.

When the operation of a machine, or accidental contact with it, could cause injury to workers or others nearby, appropriate guarding must be used as the primary safety measure.

Guarding in the form of a physical or other type of barrier can:

  • eliminate or minimise the risk of contact between people and hazardous moving parts
  • control access to dangerous moving parts, machines and equipment
  • screen harmful emissions (e.g. radiation)
  • minimise noise (use of sound-absorbing materials)
  • prevent ejected parts or off-cuts from striking people.

Safety solutions

Guarding must:

  • be of solid construction, securely mounted and resistant to impact or shock
  • prevent by-passing or disabling of the guard, and disable plant operation if it is removed
  • not create a risk in itself (e.g. it must not obstruct operator visibility, weaken the plant, cause operator discomfort or create new hazards such as pinch points or sharp edges)
  • be properly maintained, and enable ease of servicing, maintenance and repair
  • control any risk from broken/ejected parts and workpieces.

Types of guarding

Types of guarding include:

  • a permanently fixed barrier
  • an interlocked physical barrier
  • a physical barrier that can only be altered or removed with a tool
  • a presence-sensing safeguarding system
  • a distance guard placed around the perimeter of the machine

Depending on the situation, a combination of two or more different guards may be required to ensure workers’ safety.

Permanent barrier

If the area of plant requiring guarding does not need to be accessed during operation, maintenance or cleaning, then you should use a permanently fixed physical barrier.

Permanent barriers are designed to be incorporated into the body of the machine and cannot be removed, therefore eliminating the risk of injury.

Interlocked physical barrier

While permanent barriers are the most effective method of guarding, using them is often not practicable as the hazardous areas need to be accessed for various reasons, including cleaning, setting up and maintenance.

If you need to access to a hazardous area during operation, you should use an interlocked physical guard.

Interlocked guards are designed to:

  • prevent operation when doors or guards are open
  • stay locked until all machine movement has stopped
  • delay opening if moving parts take time to come to a complete stop
  • stop the machine immediately when opened
  • prevent closure if a body part is detected in the danger zone.
Food mixer with interlocking guard. Labels in the illustration direct to interlocking guard fixed onto the front of the mixer covering the bowl; on/off switches at the top centre of the mixer; emergency stop button on the right-hand side if facing the mixer.
Food mixer with interlocking guard.

If you are unable to use a permanent or interlocked barrier, you must use physical barriers that cannot be removed or modified without the use of a specialised tool.

The specialised tool should not be the same as one used when performing regular work tasks. Guarding that can be removed using fingers, for example wing nuts or wedge inserts, should not be used.

Illustration of a fixed guard on a rotating shaft or coupling. Red circular arrows at the left/foreground indicate rotation of the interconnected pieces. A label is pointing out the fixed guard: a mesh/latticed covering in a half-cylinder shape bolted over the length of the shaft.

Fixed guard on rotating shaft or coupling.

If physical barriers are securely fixed in position, they can prevent access to dangerous areas. However, isolation procedures may be necessary where there is a danger of machines activating while a person is inside the barrier. For example, when an interlocked door is accidentally closed the plant should not automatically restart.

Make sure that any physical guarding is strong enough to withstand regular wear and prolonged use, with minimal maintenance.

Illustration of a perimeter fence guard with fixed panels and interlocking access door around a machinery arm. Labels point out a danger sign displaying a "dangerous equipment" warning on the fence and the interlocking access door.

Perimeter fence guard with fixed panels and interlocking access door.

Presence Sensing

If you can’t use a permanent, interlocked or fixed physical barrier, you should use a presence sensing safeguarding device.

Presence sensing devices detect a person, or a body part approaching the danger zone and stops the dangerous operation of the plant.

Examples of presence sensing devices include pressure sensing mats, light screens and configurable scanners.

If using a presence sensing device, ensure the sensors are far enough away from the danger zone (approach distance), to allow time for the system to respond.

In addition, you must keep a record of any:

  • safety integrity tests
  • inspections
  • maintenance
  • commissioning and decommissioning
  • dismantling
  • and alterations done on the plant.

Illustration of a machine with a pressure-sensing guard. A machinery arm

Machine with a pressure-sensing guard.

Removal of guarding

If the guarding required is to be removed for the purposes of maintenance or cleaning, it must be reinstalled before the machine is put back into normal operation. The machinery must not be restarted without the guarding in place.

Guards must not be overridden or disabled. Please note, there are monetary penalties for non-compliance in this area.

Other things to consider

  • The environment the guard will be used in. For example, a wire mesh guard used on a machine that emits splashes is not appropriate guarding for that piece of plant. Consider:
    • the temperature
    • the task the machine completes
    • the materials used
    • whether the guard will be exposed to corrosion
  • Consider painting all guards the same colour, ideally a high-visibility colour that contrasts with the colour of the plant, so it is easier to see whether the guard is activated or not.

Further information