Catalogue No. SW09408
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This guide for employers and workers provides information to assist in the control or elimination of certain risks associated with the operation of a trailer-mounted handfed wood-chipper.
Wood-chippers are used in tree trimming and removal work to reduce tree waste by converting tree limbs and branches into wood chip or mulch.
Although the design of individual wood-chippers may vary, they all use the same principle of a rotating disc or drum fitted with hardened steel blades to chip the wood.
It is easier to use wood-chippers at the location where the tree has been trimmed or felled than it is to transport whole branches elsewhere to be chipped.
The list below outlines some of the common wood-chipper hazards and risks1 that can cause fatal or serious injuries to wood-chipper operators:
There are many different types of wood-chippers used in the NSW tree industry. There are also a number of different types of in-feed rollers that are used in industrial wood-chippers that can have either horizontal or vertical configuration. A number of recent incidents involved these types of machines.
Refer to Work Health and Safety Regulation 2017:
- 36 – 38 risk control measures
- 203 – Management of risks to health and safety
- 208 – Guarding
(2) The person with management or control of the plant must ensure that:
(a) “…the guarding is a permanently fixed barrier…”, or
(b) “…the guarding is an interlocked physical barrier…”, or
(c) “…the guarding used is a physical barrier requiring the use of tools…”, or
(d) if it is not reasonably practicable to use guarding referred to in paragraph (a), (b) or (c), the guarding includes a presence-sensing safeguarding system that eliminates any risk arising from the area of the plant requiring guarding while a person or any part of a person is in that area being guarded.1
Figure 1: A wood-chipping machine with in-feed rollers and a cutting disc. Source: Guide to managing risks of tree trimming and removal work, SafeWork Australia
Rotating in-feed rollers and the cutting disc or drum are the most hazardous components of wood-chipping machines.
The in-feed rollers and cutting disc are shown in Figure 1. These components may cause fatal or serious injuries to wood-chipper operators if they reach into the machine past the safety curtain (refer to Figure 2 - next page) or control bar.
Access to the cutting disc and in-feed rollers from the side or top of the unit can be prevented by a fixed or interlocked guard or covers.
Access to the cutting disc or drum can be prevented by providing interlocked physical barriers.
These may include:
An emergency stop or emergency shut-off device should be provided. This device should immediately stop the in-feed rollers and cut the power to the cutting disc or drum (which will typically have a run-down time).
The device should be immediately accessible to the operators in an emergency and tested and verified to be functioning properly during the pre-start check each time the wood-chipper is used.
The operator control bar (Figure 2) is used to set the rotation of the in-feed rollers from feed to reverse. The operating positions should be clearly identified showing the four stages of operation – reverse, neutral/stop, feed, and reverse.
On wood-chippers where the tray of the in-feed chute is less than 600 mm high, consideration should also be given to fitting side in-feed stop control bars that have the same function as the bump bar devices and are also activated by limb or body pressure.
Wood-chippers that are not fitted with an in-feed stop control device, or where the tray of the in-feed chute is less than 600 mm high, should be operated by two operators to ensure unhindered access to the emergency stop button.5
The two operators are the nominated wood-chipper operator (NWCO) feeder and the second worker/feeder. No worker should be able to come close to the in-feed rollers at any time.
If a worker comes close to the front of the drop down table or in-feed chute while the machine is in operation, the NWCO should be able to stop the rollers before this point has been reached and/or before it is breached by the worker.
For extra protection, you may consider retrofitting existing wood-chippers with an in-feed stop control device also known as a push bar or bump bar, along the bottom leading edge of the in-feed chute. This device should stop the in-feed rollers when body pressure pushes against the bar.
Consult with the wood-chipper manufacturer about retrofitting their product.
Bump bars should be painted the standard red colour as required in the Work Health and Safety Regulation.
The drop down table is fitted to the in-feed area of the wood-chipper to increase the distance between the worker and the in-feed rollers. The bump bar should be fitted under the leading edge of the table as an added precaution.
The side panels or guards fitted on each side of the drop down table protect the workers and limits the side movement, kicking or roll over of any wood being processed.
Some wood-chippers have a rubber curtain fitted to the front of the in-feed chute (see Figure 2). It is made of reinforced rubber strips that span the opening of the chute.
The safety curtain may reduce the wood chips being thrown out of the wood-chipper and hitting nearby workers. It is also an operator warning to keep hands away from the in-feed chute.
The NWCO should be able to stop the machine before this point has been reached and/or before it is breached by the worker.
Safety curtains can limit the view of the operator to ensure the rollers are grabbing the wood correctly.
If the wood-chipper has been fitted with a safety curtain, the curtain needs to be maintained and replaced when cut or damaged.
The business (or other PCBU) should have effective safety systems in place when using these machines.
Last chance stops will stop the in-feed rollers of the machine when pulled. Some machines might have these fitted.
If the worker breaches the defined danger zone, there should be adequate safe-guards in place so they do not reach the in-feed rollers.
Last chance stops might not be an effective option on their own as they require the worker to physically pull a rope. If the worker is entangled their hands or arms might not be free to activate them.
Work Health and Safety Regulation 2017 clause 208:
(2) The person with management or control of the plant must ensure that—
(d) if it is not reasonably practicable to use guarding referred to in paragraph (a), (b) or (c), the guarding includes a presence-sensing safeguarding system that eliminates any risk arising from the area of the plant requiring guarding while a person or any part of a person is in the area being guarded.
Presence-sensing safeguard system technology could also help prevent a worker coming in contact with the in-feed rollers. These types of safeguards include magnetic sensors that can be worn by operators and/or placed on operating equipment e.g. ropes.
Presence-sensing safeguard systems are incorporated into the design of some models of wood-chippers or can be fitted post-manufacture. They should be fitted and tested by the manufacturer or by a competent person before the machine is used.
Think about these control measures when purchasing a wood-chipper or retrofitting such control measures when undertaking a risk assessment on an existing machine.
All safety devices that are fitted to the wood-chipper should be regularly checked and test results should be recorded. Any identified faults should be raised with the business (or other PCBU) immediately so that repair and/or replacement of those parts can be done before the machine is used.
A woodchipper with a winch.
There should be a nominated person that is competent in the safe operation of the wood-chipper and set up of the work site. This includes:
Note: Refer to ‘Site set-up’ and ‘Pre-start checks’ in the Work site section below.
It is expected the NWCO will remain in close proximity (within 1m) to the operator control device and the bump bar at all times during the machine’s operation.Workers
Workers operating wood-chippers can also become entangled while standing beside or in front of the in-feed chute, or while they are feeding material into the wood-chipper.8
If ropes, clothing, or gloves are caught on a branch being fed into the wood-chipper, the worker can be dragged into the danger zone, past the safety curtain and the in-feed rollers onto the cutting blades.9
Ensure operating teams have at least two people who are competent in the use of wood-chipping machines and have received specific training on the individual machine being used.10 One person should oversee the operator control device and the other feed the branches into the machine.
The danger area extends out from the in-feed rollers (see Figure 3). It incorporates the wood-chipper’s feed chute and area of the drop down table. The danger zone stops at the outer edge of the drop-down table and the bump bar.
Workers outside the danger zone may still be at risk if ropes become entangled.
The shape of the feed chute extends the feed area (see Figure 4). The feed area is extended out from the danger zone as shown by the red lines out from in-feed edge of the drop-down table.
Feeding branches and brush into the chute of the wood-chipper should be done from the side of the drop-down table and not from the front of the drop-down table.
Wood can be thrown back and may kick sideways. The NWCO should ensure workers are outside the line of the feed area. If the wood kicks sideways or rolls it should only go as far as the side panel of the drop-down table allows.
The NWCO must stop the machine if the feed area is breached by a worker at any time. They must then ensure the worker has moved safely outside the feed area before the machine is re-started.
This should be considered when doing risk assessments and writing operation or work procedures.
The NWCO must stop the machine if the feed area is breached by a worker at any time. They must then ensure the worker has moved safely outside the feed area before the machine is re-started.
This should be considered when doing risk assessments and writing operation or work procedures.
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Make sure your work site is set up safely and workers consulted of the hazards and risks that can affect their health and safety on the site.11 Make sure workers have been trained in the use of the machine being operated.
When you set up the wood-chipper, ensure there is sufficient clearance from the immediate working area or drop zone to remove the risk of entanglement from climbing or lowering ropes.12
Park the machine off the road wherever possible. If this cannot be done, ensure adequate traffic management is in place.13
Traffic management measures protect workers, motorists, and pedestrians. It can include an appropriate combination of warning signs, witches’ hats, flashing amber lights, and the delineation of the work site.
Workers controlling traffic must be appropriately trained to do so (refer to the Transport for NSW website for further information) and wear high visibility (hi-vis) clothing.
Set up an exclusion zone around the machine and work area that is to be closed off to public. Put up signs and barricades to identify the exclusion zone if required.
Workers should ensure:
Caption: A worker conducting a safety check.
You can reduce the access to the in-feed rollers by:
Work Health and Safety Regulation 2017, clause 210 - Operational controls:
(1) The person with management or control of plant at a workplace must ensure that any operator’s controls are:
(d) able to be locked into the “off” position to enable the disconnection of all motive power.16
Workers should not attempt to un-block the in-feed chute when the machine is running.
The NWCO should stop the machine, allow them to clear the obstruction, move to a safe distance out of the danger zone and restart the machine. To stop the machine safely:
Make sure the wood-chipper is never unattended while in operation. The NWCO should be in a position where the operator control device can be readily activated.18, 19
Never operate the machine if there are members of the public in the exclusion zone.
When you are operating the machine, make sure you are doing so in accordance with the manufacturer’s instructions.
Feed branches into the machine off the centre line, butt first and release the material when it is gripped by the in-feed rollers.20 Do not feed wood into the wood-chipper larger than the manufacturer’s specifications.
Use a ‘push-stick’ at least 1.5m long to feed shorter material into the machine, as indicated in Figure 5.
Where reasonably practicable, the operator feeding the branches into the wood-chipper should do so from the kerb side (the side of the chipper).21
Figure 5
Do not try to retrieve any winch ropes or wood while the machine is in operation – alert the NWCO to stop the machine to retrieve the item or reverse the machine to retrieve the item.
Never put your arms or legs past the in-feed edge of the drop down table. The NWCO should stop the machine if workers are close to the drop down table and inside the danger zone. They should instruct the worker to move to a safer distance out of the danger zone or use a push stick from the side.
In Example 1, the worker appears to be working alone and leaning into the machine with the machine running (wood chips coming out of the discharge chute). This is high risk. The control must be stricter.
Caption : Example 1
Control measures to improve this example:
Work Health and Safety Act 2011 section 19 22
(c) “the provision and maintenance of safe systems of work, and….”
(f) “the provision of any information, training, instruction or supervision that is necessary to protect all persons from risks…”.
Work Health and Safety Regulation 2017 clause
39. Information, training, and instruction. 23
Develop, implement, maintain and review the use of a standard Safe Operating Procedure (SOP), Safe Work Procedure (SWP), or Safe Work Method Statement (SWMS) for wood-chipper use.
Businesses (or other PCBUs) must have safety systems in place that identify and control the risks. This may include strict operational/work procedures that are enforced by the business and the NWCO.
Work Health and Safety Act 2011 section 19 24
(f) “the provision of any information, training, instruction or supervision that is necessary to protect all persons from risks….”.
Work Health and Safety Regulation 2017 clause
39. Provision of information, training, and instruction.25
Specific training must be provided for each of the various types of wood-chippers used at workplace. Training and instruction should be recorded, as well as any refresher training provided.
Document any policies, procedures, training, instruction and site evaluations before work begins.
These should cover:
Work Health and Safety Regulation 2017 clauses
Division 5 Personal protective equipment clause 44-47.
Work Health and Safety Regulation 2017 clause
39. Provision of information, training, and instruction. 27
Personal protective equipment (PPE) is provided to workers such as eye protection, hearing protection, safety helmets, safety boots, gloves, hi-vis clothing, and is to be worn by all workers when required.
Operators should wear:
Ensure no rings, watches, necklaces, or other jewellery is worn by operators as this can be a catching hazard.28
Make sure PPE is stored correctly, maintained in good working order, and replaced if damaged, lost or worn out.
You should also have a sun protection policy in place. Make sure appropriate sun protection is provided and used by all workers such as sunscreen, sunglasses, hats with legionnaires flap, long sleeved shirts etc.29
Workers should be trained in the correct fitting, use and storage of PPE. A record of the training should be kept by the business.
Work Health & Safety Regulation 2017, Clause 210 - Operational controls:
(1) The person with management or control of plant at a workplace must ensure that any operator’s controls are:
(d) able to be locked into the “off” position to enable the disconnection of all motive power. 1
Clause 213 Maintenance and inspection of plant 30
All wood-chippers require access to the cutting disc or drum for maintenance, operation, and cleaning purposes.
Opening the access hatch or cover can allow the operator to come in contact with the moving disc or drum and expose them to the risk of entanglement, cutting and being hit by ejected fragments of vegetation or cutting blades.
Before accessing the inside of a wood-chipper, the controls for the chipper should be isolated and tagged out and/or the key removed to prevent unintentional operation of the unit.
The removal of the key while maintenance is being done ensures the machine cannot be started while work is be carried out and can only be re-instated when the work is completed.
The cutting disc or drum should be maintained to the manufacturer’s specifications or the recommendations of a competent person. A mechanical means of preventing the disc or drum from rotating should be used while performing maintenance operations.31
The maintenance or repairs should be recorded for each wood-chipper machine in the business (or other PCBU)’s control.
Australian Standard AS 4024.3701:2020 Forestry machinery – Wood-chippers