HAVS Exposure Limits Explained: Points, A(8) and What Happens at 100 and 400

Pro Site Docs · Guide

Hand-arm vibration syndrome is permanent, it is one of the most commonly reported occupational diseases in construction, and the exposure that causes it is entirely predictable from the tools and the time. The regulations set two numbers. Everything else follows from them.

The two values

The Control of Vibration at Work Regulations 2005 set an exposure action value (EAV) of 2.5 m/s² A(8) and an exposure limit value (ELV) of 5 m/s² A(8). A(8) means the daily exposure averaged over an eight-hour reference period. The HSE converts these into points to make the maths usable on site: 100 points is the EAV and 400 points is the ELV.

How points add up

Points per hour for a tool = 2 × (vibration magnitude ÷ 2.5)². So a tool at 2.5 m/s² earns 2 points an hour, 5 m/s² earns 8, 10 m/s² earns 32 and a heavy breaker at 12 m/s² earns 46. Multiply by the hours of trigger time and add up the tools used in the day. The HAVS exposure calculator does this and converts the total back to an A(8) figure for the record.

Because vibration is squared, a small change in the figure makes a big change in points. Halving the vibration quarters the exposure - which is why buying a better tool is usually the cheapest control available.

What you must do at each level

Below the EAV: keep exposure as low as reasonably practicable and keep records - HAVS is cumulative over years. At or above the EAV: reduce exposure so far as reasonably practicable through better tools, job rotation and maintenance; provide health surveillance; give information and training so people know the symptoms and report them. At the ELV: stop. The limit must not be exceeded, and there is no allowance for PPE because anti-vibration gloves are not accepted as reducing exposure.

Trigger time

The exposure clock runs only while the tool is vibrating in the hands. Measured studies consistently find that operators overestimate trigger time by two to three times - an hour 'on the breaker' is often twenty minutes of actual breaking. Where exposure is anywhere near the EAV, measure it: a stopwatch on a representative task, or a tool-mounted timer. The difference decides whether someone needs health surveillance.

Vibration figures: declared versus real

Manufacturers must declare a vibration value, measured under standard test conditions on a new tool. In-use figures on site are often higher - worn tools, blunt accessories, hard material and awkward postures all push it up. The HSE publishes typical in-use ranges by tool type; use those or, better, a measured figure for your tool. Treat the declared value as the best case.

Health surveillance

Required where exposure is likely to reach the EAV regularly, or where anyone already reports symptoms - tingling, numbness, white fingers in the cold. It starts with a questionnaire at recruitment and annually, escalating to a nurse or doctor assessment if anything is flagged. It is arranged through an occupational health provider and the records are kept for the working life of the employee plus, in practice, decades - claims come late.

Get the documents ready-made

Record it properly with a HAVS risk assessment and a daily exposure log. The occupational health templates have both, plus the health surveillance questionnaire, as editable Word documents.

General guidance only. This article explains how the rules generally work in UK construction. It is not advice for your specific site, task or project, and it is not legal advice. Your own risk assessment, method statement and arrangements must be prepared and checked by a competent person for the actual work being done.