The HAVS Exposure Points System Explained: EAV, ELV and What the Numbers Actually Mean

Why Points Instead of Hours?

Ask ten operatives how long they are allowed on a breaker and you will get ten different answers, most of them wrong. The confusion comes from treating vibration exposure as a simple time limit, when in reality the damage a tool does depends on two things at once: how hard it vibrates and how long you hold it. The Health and Safety Executive's exposure points system exists to combine those two factors into one number that anyone can add up over a working day.

The legal framework is the Control of Vibration at Work Regulations 2005. It sets two thresholds, both measured as an eight-hour energy-equivalent average called A(8). The Exposure Action Value (EAV) is 2.5 m/s² A(8), and the Exposure Limit Value (ELV) is 5 m/s² A(8). Rather than asking supervisors to do root-mean-square averaging in their heads, the HSE converted these into points: the EAV equals 100 points in a day, and the ELV equals 400 points in a day. Every trigger tool contributes points based on its vibration magnitude and trigger time, and the operative's daily total is simply the sum.

The Maths Behind the Points

The formula is straightforward once you see it: exposure points equal 2 multiplied by the vibration magnitude squared, multiplied by the trigger time in hours. A tool vibrating at 5 m/s² used for one hour scores 2 × 25 × 1 = 50 points. The same tool for two hours scores 100 points — the EAV reached in just two hours of trigger time. Because the magnitude is squared, doubling the vibration quadruples the points. That is the single most important thing to understand: a 10 m/s² breaker racks up points four times faster than a 5 m/s² one, which is why tool selection matters far more than most people realise.

Trigger time is the other half of the equation, and it is nearly always overestimated in people's heads and underestimated on paper. An operative who has a breaker for the whole shift might only have the trigger pulled for 40 minutes of it. Positioning, moving spoil, changing points and standing back for the excavator all count as rest from the tool's point of view. Good HAVS management measures or realistically estimates trigger time rather than booking the whole task duration against the tool.

What You Must Do at Each Threshold

Below 100 Points

You still have a general duty to reduce vibration risk so far as is reasonably practicable, but no specific programme is triggered. Sensible sites still record exposure so they can prove where people sit.

At or Above 100 Points (the EAV)

You must introduce a programme of organisational and technical measures to reduce exposure: lower-vibration tools, job rotation, better work methods, maintenance regimes that keep tools cutting efficiently, and health surveillance for exposed employees. Health surveillance is not optional above the EAV — it is a legal requirement, typically delivered through a tiered questionnaire and occupational health referral system.

At or Above 400 Points (the ELV)

This is a hard ceiling. Exceeding the ELV is a breach of the regulations, full stop. If an operative is approaching 400 points, they come off trigger tools for the rest of the day — the programme, the pour and the deadline are all irrelevant. On well-run sites the ELV should never even come into view, because the management effort happens down at the EAV.

Where the Magnitude Numbers Come From

Manufacturer declared values are measured to standardised test codes and are useful for comparing tools against each other, but they routinely understate real in-use vibration because the test conditions are gentler than site conditions. HSE guidance has long recommended applying a correction or using measured field data where available. A practical approach is to use the manufacturer figure for procurement decisions but plan daily exposure with either measured data or the manufacturer figure uplifted, so your points budget has margin in it. Whatever source you use, record it — when an occupational health provider or an inspector asks how you calculated an operative's A(8), the answer needs to be written down, not remembered.

Running the System Day to Day

The mechanics of a working HAVS system are simple to describe and easy to let slip. Every trigger tool on site needs a known vibration magnitude and a points-per-hour rate. Every operative using those tools needs their trigger time recorded daily — genuinely daily, not reconstructed on Friday afternoon. Someone needs to add the points up and act before anyone crosses a threshold, not after. And the records need to survive long enough to support health surveillance, because HAVS claims surface years after the exposure.

Paper systems can do this, but they fail in predictable ways: tools without data plates, operatives on multiple tools across multiple gangs, and the Friday reconstruction problem. Digital tracking makes the arithmetic automatic and the threshold warnings immediate. Whichever route you take, the test is the same: can you say, right now, how many points each of your operatives accrued yesterday, and can you prove it?

The Mistakes That Keep Coming Up

Three errors account for most HAVS failures I see. First, booking task time as trigger time, which either wildly overstates exposure (and takes tools off people unnecessarily) or teaches everyone that the numbers are fiction. Second, treating the EAV as the limit and coasting up to 100 points daily with no reduction programme — the EAV is the point where you must act, not a ration to be spent. Third, ignoring the sub-100 population entirely, so when someone reports tingling fingers there is no exposure history to give occupational health.

A fourth, subtler one: assuming new tools stay at their catalogue vibration figure forever. Blunt steels, worn dampers and poor maintenance push magnitudes up over time. A maintenance regime is a vibration control, and it belongs in your reduction programme alongside rotation and tool selection.

Health Surveillance Is Half the System

Exposure control stops new damage; health surveillance catches damage early enough to matter. Above the EAV, exposed employees need a structured programme — typically annual screening questionnaires with escalation to a qualified occupational health professional where symptoms appear. HAVS is irreversible but progressive: caught at stage 1, an operative can usually keep working with reduced exposure; caught at stage 3, their career with vibrating tools is over. The point of surveillance is to make sure nobody travels from stage 1 to stage 3 unnoticed.

Pulling It Together

The points system is the friendliest piece of maths in construction health and safety: two times magnitude squared times hours, keep everyone under 100 where you can, never let anyone near 400, and write it all down. The hard part is not the arithmetic — it is running the recording discipline every single working day. Get that habit embedded and HAVS becomes one of the most controllable occupational health risks on your site rather than the slow-motion claim generator it is on sites that leave it to memory.