This guide is for persons conducting a business or undertaking (PCBUs) that carry out work involving hand-held power tools and machines. It explains how to identify and manage the risks from hand-arm vibration (HAV).

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Hand-arm vibration – information for businesses (PDF 445 KB)

1.0 Who is this guide for?

Vibration from tools and machines can be transmitted into workers’ hands and arms. Workers can be permanently harmed if they regularly and frequently use hand-held power tools and machines, especially for long periods of time.

As a PCBU1, you must ensure, so far as is reasonably practicable, the health and safety of workers, and that other persons are not put at risk by your work.

You must manage the health and safety risks to workers and others that arise from being exposed to the work carried out by your business.

2.0 What are the health and safety risks from HAV?

Workers can develop hand-arm vibration syndrome (HAVS) or carpal tunnel syndrome (CTS) if they regularly and frequently use hand-held power tools and machines, especially for long periods of time.

What are symptoms of HAVS and CTS?

[Image] diagram showing symptoms of Havs and CTS
FIGURE 1: Symptoms of HAVS and CTS

 

The symptoms can come and go, but with continued exposure to HAV, symptoms can become prolonged or permanent. This could happen after only a few months of exposure, but in most cases it will take a few years.

As a result, workers could experience pain, distress and disturbed sleep.

HAV could also make existing hand injuries or illnesses workers have worse.

People who are exposed to noise and vibration at the same time are more likely to lose their hearing than people who are exposed to noise alone.

For information about vibration noise control, see our website: worksafe.govt.nz

What can happen if the symptoms are ignored?

If the symptoms are ignored, the damage can become permanent and disabling. As a result, workers may not be able to do simple tasks like opening jars or using a phone. Workers may have to stop working with vibrating equipment if they can no longer safety handle tools/machines.

3.0 How can you work out if exposure to HAV is something you need to deal with?

Different power tools and machines produce different amounts of vibration. Power tools and machines that are older or not well-maintained usually vibrate more.

The use of power tools and machines – typically high vibration ones – is linked to HAVS and CTS. These include using hand-held or hand-guided tools like:

  • chainsaws
  • jackhammers/demolition hammers/demolition breakers
  • hammer drills
  • jigsaws
  • sanders
  • hand-held grinders
  • weed whackers/line trimmers
  • powered sanders
  • pneumatic drills
  • powered lawn mowers.

HAVS and CTS are seen in industries such as forestry, metal working, demolition, road repair, construction, heavy engineering and foundries.

Do you need to manage the risks from HAV?

This will depend on how much the power tools and machines workers use vibrate, and how long and how often workers are exposed to the vibration.

There is a recommended maximum daily amount of HAV that workers should not exceed.

  • We recommend that workers have a maximum daily exposure limit of 5m/s2 (8 hour average).
  • We expect you to put control measures in place if your workers are exposed to ‘the exposure action value’ of 2.5m/s2 (8 hour average) or more.

See Section 4 for information about monitoring the amount of vibration workers are being exposed to.

There are many factors that can influence the effects of exposure to HAV. These include:

  • the condition of the power tool/machine
  • the vibration intensity
  • the duration of exposure (time/day, frequency)
  • the temperature the work is being carried out in
  • operator technique (for example, how hard the worker grips the power tool/machine)
  • operator health and medical history (including if they smoke).

To work out whether your workers are at risk, think about:

  • the power tool/machine
  • how the work is organised
  • the task
  • your workers.

Figure 2 shows things to consider.

You must engage with workers and their representatives when assessing risks to work health and safety (Appendix 4).

Section 4 describes how monitoring can help to identify or confirm health risks from HAV.

Think about...

 

The power tool/machine

What is the vibration level of the power tool/machine?

See the manufacturer’s user manual or specification.

Is the power tool/machine regularly maintained?

There is greater vibration when power tools and machines are not well maintained.

Blunt tools mean tasks take longer, meaning more exposure to vibration.

Is it a heavy hand-held power tool/machine?

Tighter grip is needed for heavier power tools and machines. Gripping too tightly increases the chances of developing HAVS or CTS.

Does a large area of the hand contact the power tool/machine?

The larger the areas of contact, the more vibration workers are exposed to.

Does it have a well-insulated handle?Poorly insulated handles mean workers are exposed to more vibration.

 

The task

Is the power tool/machine the right one for the task?

Using the wrong power tool/machine can mean work takes longer, increasing exposure to vibration.

Using over-powered tools expose workers to higher levels of vibration.

What is the vibration level for the task and how long does the task take? 

See the manufacturer’s user manual or specification for vibration data. The higher the vibration, the greater the risk.

What is the hardness of the material the power tool/machine will contact (for example, is it concrete, is it wood, is it soft soil)?

The harder the material, the more vibration.

Does the task involve workers lifting power tools overhead or other awkward postures?

Tighter grip is needed for awkward postures. Gripping too tightly increases the chances of developing HAVS or CTS.

 

How the work is organised

How long are your workers exposed to the vibration?

  • How many hours within the shift involve operating the power tool/machinery?
  • How often do your workers take breaks?
  • How long are they exposed to high levels of HAV versus lower levels?
  • How often do they operate the power tool/machine? Every day?

The longer workers are exposed to vibration, the more chance of developing HAVS or CTS.

Is the work in cold environments?

Cold increases the chances of developing HAVS or CTS.

 

Your workers

Do your workers always use the right power tool/machine for the job?

Using the wrong power tool/machine can mean work takes longer, increasing exposure to vibration.

Have they been trained how to properly use the power tool/machine? Do they have poor technique (awkward postures) or grip the power tool/machine more tightly than needed?

Gripping more tightly than needed increases the chances of developing HAVS or CTS.

Are they being exposed to HAV above the recommended levels?

See page 4 for recommended levels.

Have workers previously reported symptoms of HAVS or CTS (as described in Section 2)? Have you asked workers recently if they are having any early signs?

Do they smoke?

Smoking decreases blood circulation and increases the chance of HAVS.

How is their general health?

Medical conditions such as diabetes and arthritis, and injuries such as frostbite increases the chances of developing HAVS or CTS.

Are there any tools to help?

The Health and Safety Executive (UK) has tools to help work out whether workers could be being exposed to HAV exceeding the exposure action value (2.5m/s2 (8 hour average)).

These tools are:

To use these tools, you will need to know:

  • the amount of time your workers use the power tool/machine, and
  • the vibration emission levels of the power tool/machine.

Look in the manufacturer’s user guide or specification for the emission information.

If you exceed the exposure action value, we recommend:

  • implementing control measures first to eliminate/minimise exposure levels (see Section 5 for guidance on this), and
  • bringing in a competent person2 to measure HAV exposure and the effectiveness of control measures (See Section 4).

Example using the ready reckoner

You have identified the tasks your workers carry out that are a risk for HAV. They use an angle grinder for 1 hour/day and a power drill for half an hour/day. From the manufacturer’s guide, the vibration data for the angle grinder is 7m/s2 and power drill is 5m/s2.

Using the ready reckoner tool(external link) the angle grinder corresponds with 98 points and the power drill results in 25 points. Adding them together gives 123 points, which is above the exposure action value total of 100 points.

This means that workers are potentially at an elevated risk, and you should:

  • eliminate/minimise the risks of exposure to HAV
  • engage a competent person to carry out exposure monitoring of the actual HAV exposures and risk, and
  • introduce health monitoring that is carried out by a competent person.

4.0 How can monitoring be used to identify health risks and check control measures?

You must ensure, so far as is reasonably practicable3, the health and safety of workers, and that other people are not put at risk by your work. In some circumstances, this could mean monitoring worker exposure and/or the health of workers.

Exposure monitoring measures and evaluates what your workers are being exposed to while they are at work.

Health monitoring looks at whether a worker’s health is being harmed because of what they are being exposed to while they are at work.

Monitoring should be carried out by a suitably qualified person with sufficient knowledge, skills, training and experience.

Monitoring is not a control measure. It does not replace the need for control measures to eliminate or minimise worker exposure to harm.

For more information about exposure monitoring and health monitoring, read our guidance: Exposure monitoring and health monitoring: Guidance for businesses

Exposure monitoring can be used to:

  • identify, assess and confirm health risks
  • identify where new control measures are needed
  • monitor how well existing control measures are performing, and
  • identify when control measures need to be reviewed, updated or removed.

Health monitoring can be used to monitor if workers are experiencing injury or illness from exposure.

As shown in Figure 3, monitoring information – along with verifying that your control measures are working effectively – can be used to continually improve how you are managing health risks.

For more information about managing risk, see Section 5.

[Image] Diagram showing how to monitor when managing risk.
FIGURE 3: Role of monitoring when managing risk

When is it recommended to carry out exposure monitoring?

We recommend bringing in a competent person (such as an Occupational Hygienist) to measure worker exposure when the results of your risk assessment indicate an elevated risk of exposure to HAV.

An example of this would be a ready reckoner score of over 100 (see Section 3). Another example is if workers complain of HAV-related symptoms.

When is it recommended to carry out health monitoring?

One aim of the health monitoring is to stop workers developing a disabling loss of hand function.

We recommend health monitoring is carried by a competent person when the results of your risk assessment indicate an elevated risk of exposure to HAV.

As described in Table 1, health monitoring is recommended:

  • at the start of employment (to identify workers at increased risk, and to get baseline information)
  • within six months of commencing work (to identify any early onset of symptoms) and then on a regular basis (for example, yearly).

What could exposure monitoring and health monitoring involve?

Table 1 shows examples of exposure monitoring and health monitoring.

  Exposure monitoring Health Monitoring
What does it involve?

Exposure monitoring measures the amount of vibration workers’ arms or hands are exposed to using measurement equipment
in accordance with standards.

Results are measured against the exposure action value and exposure limits value. The risk to worker health is then assessed.

Health monitoring checks for nerve, muscle or circulation damage in hands, wrists and arms.

Health monitoring could involve the following:

  • At the start of employment, workers fill out an initial questionnaire4, and then after six months.
  • Workers then fill out a questionnaire4 on an annual basis.
  • If questionnaire results indicate concerns, the worker undergoes a HAVS/CTS health assessment.
  • When HAVS/CTS is suspected, the worker is sent for a full medical assessment/formal diagnosis.

Note: Workers must give their informed consent(external link) for health monitoring. You must keep any personal information collected during monitoring secure and confidential, and use it for the purposes it has been collected for. For more information: Privacy Act 2020 principles(external link)

Who carries it out?

Exposure monitoring should be carried out by a competent person (or person under the supervision of a competent person), such as an Occupational Hygienist.

This person should have sufficient knowledge, skills, and experience in appropriate techniques and procedures, including the interpretation of results.

Health monitoring should be carried out by occupational health practitioners with relevant training, skills and experience in health monitoring.

For example:

  • An Occupational Health Nurse reviews the initial and annual questionnaires, and carries out HAVS and CTS health assessments (where needed).
  • If HAVS or CTS is suspected, workers will be referred to an Occupational Physician for a full medical assessment/formal diagnosis.

Workers should not be exposed to further HAV until this full medical assessment takes place.

As a result of this assessment, you will receive a recommendation as to whether the worker should continue to work with power tools/machines. You should follow this recommendation.

TABLE 1: Examples of HAV exposure monitoring and health monitoring

You should talk to a suitably qualified person with sufficient knowledge, skills, training and experience to confirm if monitoring is appropriate for you (and if so, what type and how often).

You must engage with workers and their representatives when making decisions about monitoring procedures (Appendix 4). Discuss with workers how exposure to HAV can harm them, and how monitoring can be used to manage health risks.

For more information on monitoring, including setting up monitoring programmes and what to do if monitoring results show workers are being harmed or at risk, read our guidance: Exposure monitoring and health monitoring: Guidance for businesses

5.0 How can you manage the health and safety risks from HAV?

If you need to manage the risks from HAV, you could:

  • reduce the amount of vibration workers are exposed to
  • reduce the time workers are exposed to vibration (over each shift, over the time they work for you)

or ideally both.

You must work with other businesses you share monitoring duties with

You must work together with other PCBUs if you share health and safety duties (this could happen when you share a workplace or you are in a contracting chain). A shared duty could include managing shared risks (including those from HAV) or carrying out monitoring of the same worker. For more information about working with other businesses, see Appendix 3.

You must engage with your workers about health and safety matters

Seek the views of your workers and their representatives when identifying and assessing the risks from exposure to HAV, and when making decisions about the ways to eliminate or minimise those risks. For more information about engaging with workers, see Appendix 4.

What control measures could you consider?

You must first try to eliminate a risk so far as is reasonably practicable.

If it is not reasonably practicable to eliminate the risk, it must be minimised so far as is reasonably practicable.

You can use the hierarchy of control measures to help you to work out the most effective control measures to use.

Figure 4 describes control measures you could use to eliminate or minimise the risks arising from HAV. Multiple control measures may be needed to deal with a given risk. Give preference to control measures that protect many workers at the same time.

Put the control measures in place

As soon as possible after a decision is made about the control measures:

  • put the control measures in place
  • instruct and train workers (including new workers) about the control measures, including why it is important to use them and how to apply them.
[Image] diagram showing possible control measures
FIGURE 4: Possible control measures

6.0 When should you review and improve your HAV control measures?

Control measures should remain effective, and be fit-for-purpose, suitable for the nature and duration of the work, and used correctly.

With your workers, regularly monitor and review control measures to confirm that the measures are effective.

As discussed in Section 4, exposure monitoring can be used to monitor how well control measures are performing, and to identify when control measures need to be reviewed, updated or removed.

Get advice from a competent person on how often to monitor the effectiveness of control measures.

However you should immediately investigate, and review your control measures when:

  • the control measure does not control the risk, or
  • a new hazard or risk is identified, or
  • workers report symptoms of HAVS and CTS to you, or
  • you receive exposure monitoring or health monitoring results that show your workers are being harmed or at risk from HAV (Section 4), or
  • there will be a change in the workplace or work (for example, new equipment, new or changed work processes, increased workload, extended hours or additional/changed shifts), or
  • your workers or their representatives indicate a review is necessary or request it.

Use the results of these reviews to continually improve how you manage health risks.

Footnotes

1. PCBUs have duties under the Health and Safety at Work Act 2015 (HSWA). For explanations of HSWA and more information about PCBUs, see Appendix 1.

2. A ‘competent person’ is someone who has sufficient knowledge, skills, training and experience in the appropriate techniques
and procedures, including the interpretation of results – such as an Occupational Hygienist for exposure monitoring.

3. See Appendix 2 for an explanation of what ‘so far as is reasonably practicable’ means.

4. Examples of initial and annual questionnaires can be found on the HSE website.(external link)

Appendices

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Appendix 1: Health and Safety at Work Act duties (PDF 44 KB)
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Appendix 2: So far as is reasonably practicable (PDF 29 KB)
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Appendix 3: Appendix 3: Working with other PCBUs – overlapping duties (PDF 27 KB)
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Appendix 4: Worker engagement, participation and representation (PDF 40 KB)