Hand-Arm Vibration Assessments

What Is a Hand-Arm Vibration Assessment?

A hand-arm vibration (HAV) assessment measures the vibration your team is exposed to from tools such as breakers, grinders and compactors. Regular use of vibrating tools can cause hand-arm vibration syndrome.

Hand-arm vibration syndrome can damage the blood vessels, nerves and joints of the hands and arms, with symptoms such as tingling, numbness, loss of grip strength and fingers turning white in the cold. Carpal tunnel syndrome can also be linked to vibration exposure. The damage is often permanent, so preventing excessive exposure is far more effective than treating it later.

Wave Dynamics measures vibration on the tools your team uses, calculates daily exposure for each task and gives practical advice to reduce it.

Why Employers Need One

Employers must assess the risk from vibrating tools and keep daily exposure below the legal limits. The exposure action value is 2.5 m/s² A(8) and the exposure limit value is 5 m/s² A(8).

Above the exposure action value, employers must put in place a programme of measures to reduce exposure as far as reasonably practicable and provide information and training to the workers affected. The exposure limit value must not be exceeded. Health surveillance is also needed for employees who are at risk, so that early signs of injury are picked up and acted on. Construction, utilities, manufacturing, grounds maintenance and engineering workshops are typical sectors where these duties apply.

How Daily Exposure Is Calculated

Daily exposure depends on two things: the vibration magnitude of the tool and the length of time the operator is in contact with it. A(8) expresses this as an equivalent vibration level averaged over an eight-hour day.

Vibration is measured on the tool handle in three directions and combined into a single vibration total value. Because exposure scales with the square root of time, halving trigger time does not halve A(8): a tool producing 10 m/s² reaches the exposure action value after about 30 minutes of trigger time and the exposure limit value after about two hours.

Where an operator uses several tools in a day, the partial exposure from each is combined into one daily figure. In the UK, the HSE exposure points system expresses the same calculation in a simpler form, where 100 points equals the action value and 400 points equals the limit value.

What We Do

Vibration measurements on tools in normal use
Daily exposure A(8) calculations for each task and operator
Comparison with the exposure action and limit values
Hand-arm vibration risk assessment reports
Advice on tool selection, maintenance, job rotation and trigger times
Combined assessments with noise at work and workplace air quality

For the noise side of a combined visit, see our workplace noise assessments.

Our Approach

Review: we list the tools in use, the tasks they are used for and how long each operator typically spends on them.
Measure: we fit a tri-axial accelerometer to the tool handle and record vibration while operators carry out their normal work on real materials.
Observe: we check trigger times on site, as operators often overestimate how long they actually use a tool.
Calculate: we work out A(8) for each operator and task and compare it with the action and limit values.
Advise: we set out the practical changes that will bring exposure down, in order of effectiveness.

Legislation and Standards

Safety, Health and Welfare at Work (General Application) Regulations 2007, Part 5 Chapter 2 (Ireland)
Control of Vibration at Work Regulations 2005 (UK)
I.S. EN ISO 5349-1 and 5349-2
Exposure action value 2.5 m/s² A(8)
Exposure limit value 5 m/s² A(8)

I.S. EN ISO 5349-1 sets out how hand-transmitted vibration is evaluated, and I.S. EN ISO 5349-2 gives practical guidance on measurement at the workplace.

Common Issues and How We Avoid Them

Manufacturer declared vibration values are measured under standard test conditions and can understate what happens on site, where worn bits, blunt discs, hard materials and poor tool condition all increase vibration. That is why we measure tools in normal use wherever possible.

Other common gaps are risk assessments that list tools but not how long each person uses them, and control measures that rely on job rotation alone. Lasting reductions usually come from a combination of measures: choosing lower vibration tools when replacing equipment, keeping tools well maintained, changing the work method so a tool is not needed, and managing trigger time.

Anti-vibration gloves are often relied on, but their effect on the frequencies that cause injury is limited and hard to predict, so they should not be treated as a control in their own right. Ordinary gloves are still worth wearing, as keeping hands warm and dry helps blood circulation and reduces the risk of symptoms developing.

What You Receive

A hand-arm vibration risk assessment report that can sit directly within your health and safety management system, showing the measured vibration for each tool and task, the daily A(8) exposure for each operator, and a clear comparison with the action and limit values. Where exposure is too high, the report sets out recommended trigger time limits and practical control measures that supervisors can put into practice straight away. We also highlight which tools are good candidates for replacement, so that purchasing decisions help to reduce exposure over time.

We support employers across Ireland and the UK from offices in Dublin, Wexford, Cork, Belfast and London. For vibration affecting buildings and occupants rather than workers, see our vibration services.

Frequently Asked Questions

What are the hand-arm vibration exposure limits?

The daily exposure action value is 2.5 m/s² A(8) and the exposure limit value is 5 m/s² A(8), in both Ireland and the UK. Both are daily values, so a short period on a high vibration tool can be acceptable while a full shift on the same tool may not be.

Can manufacturer vibration data be used instead of measurements?

Manufacturer data is a useful starting point, but measurements under real working conditions give a more reliable estimate of exposure. Declared values are best used to compare tools when buying, and to prioritise which tools to measure on site.

What does a HAV assessment include?

Vibration measurements on tools in normal use, daily A(8) exposure calculations for each task and operator, comparison with the action and limit values, and practical advice on reducing exposure. The findings can be used directly in your risk assessment and toolbox talks.

Can you assess noise and air quality at the same time?

Yes. We carry out combined assessments covering hand-arm vibration, noise at work and workplace air quality. Many tools that vibrate heavily, such as breakers and disc cutters, are also loud and create dust, so assessing them together saves time on site and gives a fuller picture of the risk.

Does the assessment disrupt work?

Very little. Operators carry on with their normal tasks while a small accelerometer is attached to the tool handle. In fact, normal working conditions are what we need to measure, so we plan the visit around tasks that are representative of a typical day.

Which tools should be assessed first?

Start with tools used for long periods and those known for high vibration, such as breakers, hammer drills, angle grinders, disc cutters, needle scalers and plate compactors. Operators who report tingling or numbness, or who use several vibrating tools in a shift, should also be a priority.