Construction worker in hi-vis and gloves breaking concrete with a breaker that has a HAV tag on the handle

HAV points system explained: how to work out daily vibration exposure

If your teams use breakers, grinders, hammer drills or saws, hand-arm vibration (HAV) is part of the job. The law doesn't ask you to stop using those tools. It asks you to know how much vibration each person is taking in, keep it as low as reasonably practicable, and never let it go over the daily limit.

The simplest way to do that is the HSE exposure points system. This guide explains what the numbers mean, how to work out points per hour and maximum daily use for any tool, and how to add up a day on more than one tool. It also shows how to get that information onto the tool itself, where the operative can see it.

What the Control of Vibration at Work Regulations 2005 require

The Control of Vibration at Work Regulations 2005 set two daily values for hand-arm vibration:

  • Exposure action value (EAV): 2.5 m/s² A(8). HSE describes this as a clear risk requiring management. At or above it, you must take action to reduce exposure.
  • Exposure limit value (ELV): 5 m/s² A(8). This is the maximum daily exposure. It must not be exceeded.

"A(8)" means the exposure is averaged over an eight-hour working day, so it reflects both how hard a tool vibrates and how long someone is holding it.

According to HSE's brief guide INDG175, the Regulations require you to control the risks from vibration, give employees information, instruction and training, and provide suitable health surveillance. Your duty is to reduce risk to the lowest level reasonably practicable. That applies at every level of exposure, not just above the action value.

EAV and ELV in points: 100 and 400

Working in m/s² A(8) involves square roots and averaging, which is awkward on site. HSE's points system turns it into simple addition:

Daily value m/s² A(8) Exposure points
Exposure action value (EAV) 2.5 100
Exposure limit value (ELV) 5.0 400

Source: HSE, Control of Vibration at Work Regulations 2005 and HSE exposure calculator guide.

So the rule of thumb is: 100 points a day means act, and 400 points a day means stop.

Working out points per hour and maximum daily use

Every tool's points depend on two things:

  1. Vibration magnitude in m/s², the level of vibration at the handle.
  2. Trigger time, the time the operative's hands are actually on the tool while it is running. This is not the length of the shift or the time the tool is booked out.

HSE publishes a simple table of approximate points per hour on its vibration risk assessment page:

Tool vibration (m/s²) 3 4 5 6 7 10 12 15
Points per hour (approx.) 20 30 50 70 100 200 300 450

For a magnitude that isn't in the table, the figures come from a simple formula:

Points per hour = 2 × (vibration magnitude)²

For example, a 5 m/s² tool gives 2 × 25 = 50 points per hour, and a 10 m/s² tool gives 2 × 100 = 200 points per hour. HSE's table rounds some values (a 6 m/s² tool works out at 72, shown as 70).

Once you know points per hour, the maximum daily use follows:

  • Time to reach the EAV = 100 ÷ points per hour
  • Time to reach the ELV = 400 ÷ points per hour

Using a 10 m/s² tool (200 points per hour):

  • EAV reached after 100 ÷ 200 = 0.5 hours (30 minutes) of trigger time
  • ELV reached after 400 ÷ 200 = 2 hours of trigger time

HSE's exposure calculator, a free spreadsheet, does the same sums for up to six tools at once and shows the time to reach the EAV and ELV for each.

Where the vibration figure comes from

HSE's guide notes that manufacturers must declare vibration emission in their literature, but that this figure "should be, but is not always" suitable for estimating real exposure. Check it with the manufacturer or your supplier, use in-use data where you have it, and use the HSE calculator's recommended initial values where you don't. A worn, damaged or wrong-for-the-job tool can vibrate much more than its declared figure.

How to measure trigger time

HSE points out that operatives are unlikely to estimate their own trigger time accurately. A practical approach from HSE's guidance is to watch and time the work for a sample period, such as half an hour, and scale it up to the shift. For repetitive work, such as drilling many holes, you can time a few holes and multiply by the number drilled in a day.

Adding up a day on more than one tool

Points are additive, which makes the system useful on a real job. Here is an illustrative example. The vibration values are made up for the arithmetic and are not data for any particular tool.

Task Magnitude Points per hour Trigger time Points
Hammer drilling anchors 10 m/s² 200 45 minutes 150
Grinding back 5 m/s² 50 1.5 hours 75
Day total 225

At 225 points the operative is above the EAV (100) and below the ELV (400). The work can continue today, but you need a programme of measures to bring exposure down, plus health surveillance and training for those regularly exposed at this level. If the plan for the afternoon would take the total past 400, the work must be reorganised: rotate operatives, change the method or use a lower-vibration tool.

For a quick check before a job, HSE gives these rules of thumb for modern, well-maintained power tools (INDG175):

  • Hammer-action tools: EAV likely after about 15 minutes, ELV after about one hour.
  • Non-hammer tools: EAV likely after about one hour, ELV after about four hours.

What to do when exposure is above the action value

When daily exposure is likely to reach or exceed 100 points, HSE's guidance on the Regulations (L140) says you need a formal programme of measures to minimise risk, including exposure controls, health surveillance and training. In practice:

  • Change the method so less vibrating work is needed, for example by designing out scabbling or breaking.
  • Choose lower-vibration equipment that suits the task, and keep it maintained (sharp bits, balanced discs, working anti-vibration mounts).
  • Limit trigger time by planning and rotating work.
  • Provide health surveillance for employees likely to be regularly exposed above the EAV, or otherwise at risk. See HSE's advice for employers.
  • Train and inform operatives so they know their tools' points and the early symptoms: tingling, numbness and whitening fingers.
  • Report certain cases of HAVS and all cases of vibration-related carpal tunnel syndrome under RIDDOR, as INDG175 sets out.

Don't forget the dust

Breaking, scabbling, chasing and grinding concrete or masonry are high-vibration jobs, and they often create fine silica dust too. HSE's construction dust guidance covers controls such as on-tool extraction and respiratory protective equipment (RPE). In enclosed work areas, a HEPA air cleaner such as the DC Aircube 500 can run alongside on-tool extraction to help clear fine dust from the air. Where your risk assessment calls for supplied-air RPE, an air-fed kit such as the Honeywell Airvisor 2 air-fed half mask kit is one option. See our dust control and respiratory PPE ranges.

Putting the numbers on the tool: HAV tags

A risk assessment in an office doesn't help the operative holding the tool. The simplest way to share the numbers is to tag each tool.

GO2's HAV Tag Daily Use is a flexible TPU tag with laser-etched printing. It has space to write the tool ID, vibration magnitude (m/s²), maximum daily use in minutes and noise level dB(A) in permanent marker. It resists oil, grease, solvents, acids and alkalis and handles high and low temperatures. The tag measures 54 x 74 mm and comes in green, orange, red, white, blue and yellow.

Many sites use a colour scheme so crews can tell high-vibration tools at a glance. Whatever scheme you choose, write it into your HAV procedure and toolbox talks so every colour means the same thing on every site. See the full range in Safety Tags.

Remember that a tag supports your system. It doesn't replace a risk assessment, trigger-time records or health surveillance.

Frequently asked questions

What is 100 HAV points?

100 points is the daily exposure action value (EAV) of 2.5 m/s² A(8). At or above it, the law requires action to reduce exposure, including health surveillance and training for those regularly exposed.

How many HAV points are you allowed per day?

The daily exposure limit value is 400 points, equal to 5 m/s² A(8). It must not be exceeded, so plan tasks, tool choice and rotation to keep every operative below it.

How do I calculate HAV points per hour?

Multiply the tool's vibration magnitude by itself and double it: points per hour = 2 × (m/s²)². A 7 m/s² tool gives about 100 points per hour. Then multiply by the hours of trigger time.

Is it safe to stay just under 100 points?

Not automatically. The Regulations require risk to be reduced as far as reasonably practicable at any level of exposure. HSE also notes that some people develop early signs of HAVS or CTS even at low exposures, for example if they're susceptible and regularly exposed at around the action value. Aim to keep exposure as low as you reasonably can.

Can I use the manufacturer's vibration figure?

You can start with it, but HSE notes that declared values aren't always representative of real use. Check with the manufacturer or supplier, and use in-use data or HSE's suggested values where they're more realistic.

What counts as trigger time?

Only the time the tool is running with the operative's hands on it. Breaks, set-up and moving between tasks don't count. Observing and timing the work is more reliable than asking operatives to estimate.

Kit for safer, cleaner sites

Tag every vibrating tool with its magnitude and maximum daily use so the numbers are where the work happens. Order HAV Tag Daily Use, or email sales@go2supplies.co.uk about bulk quantities and trade accounts.

Need lower-vibration tools, a different tag format or something we don't list? Can't source it? GO2 supplies it. Tell GO2 Source the product, brand or part number and we'll come back to you by email.

Sources

This article is general guidance and isn't a substitute for your own risk assessment or competent health and safety advice.

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