How to Log HAVS Exposure on Site Every Day: A Supervisor's Routine
Most HAVS guidance tells you what the law requires — risk assessments, exposure limits, health surveillance. Far less of it tells you how to actually capture exposure data on a live site, on a busy day, with a crew that just wants to get the job done. Yet that daily record is the thing HSE asks to see first, and the thing most small firms can't produce.
This guide is the practical version. It's written for the site supervisor or working foreman who has to make daily logging happen — not in an office, but in the cab, the welfare unit, or stood next to a breaker. It covers what to log, when to log it, and how to keep the habit alive past the first fortnight.
Why a Daily Log, Not a Weekly Estimate
Hand-arm vibration exposure is measured per day. The Control of Vibration at Work Regulations 2005 set a daily Exposure Action Value (EAV) of 2.5 m/s² A(8) and a daily Exposure Limit Value (ELV) of 5 m/s² A(8). "A(8)" means averaged over an eight-hour day — so the question the regulations ask is always what was this worker exposed to today?
That's why a weekly estimate doesn't work. A worker can spend four quiet days drilling pilot holes and one brutal day on a breaker. The weekly average looks fine; the breaker day blew straight through the ELV. Only a daily record catches the day that matters.
It's also why memory doesn't work. Ask a groundworker on Friday how long they were on the breaker on Tuesday and you'll get a guess — usually an under-estimate, because short high-vibration bursts feel shorter than they are. A scabbler at 30 m/s² hits the EAV in under four minutes of trigger time. Get the estimate wrong by ten minutes and you've misjudged a legal breach. The log has to be made on the day, close to the work.
What to Record Each Day
You don't need a long form. You need four things per worker, per day:
| What | Example | Why it matters |
|---|---|---|
| Which tools they used | Pneumatic breaker; 9" angle grinder | Each tool has its own vibration magnitude |
| The vibration magnitude (m/s²) of each | Breaker 18; grinder 7 | Drives the exposure points |
| Trigger time on each tool | Breaker 25 min; grinder 40 min | Hands-on time, not shift time |
| Total exposure points (and EAV/ELV reached?) | 555 points — ELV exceeded | The figure that triggers action |
Trigger time is the one people get wrong, so it's worth being clear: it's the time the worker's hand is actually on the running tool, not the length of the task and definitely not the length of the shift. A worker on site for eight hours might have 45 minutes of genuine trigger time. The log records the 45 minutes.
If you don't know a tool's vibration magnitude, get it from the manufacturer's data sheet or the tool manual — it's a declared value. As a fallback for planning, the HAVS Trigger Time Chart and the trigger time reference table give typical ranges for common tools, but a logged record should use your actual tool's declared figure where you have it.
When to Log It: Three Workable Patterns
The single biggest reason daily logs fail is timing — leave it to the end of the day and it becomes a guessing exercise, or it doesn't get done at all. Pick the pattern that fits how your crew works:
1. Log at the tool change. Every time a worker finishes with a vibrating tool and moves to something else, that's the natural moment to note the trigger time while it's fresh. Best for crews doing varied work with several tool swaps a day.
2. Log at break and end of shift. Two fixed points — morning break and knocking-off time — where the supervisor walks the crew and captures what each person has been on. Best for crews on one sustained task (a day of breaking out, a day of compacting).
3. Worker self-logs, supervisor checks. The worker notes their own trigger times as they go; the supervisor verifies and totals at the end of the day. Best for experienced crews who understand the EAV — and it doubles as awareness-building. Reinforce it with a short HAVS toolbox talk so everyone knows why it matters.
Whichever you choose, the rule is the same: capture trigger time close to the work, total the points before everyone goes home.
A Worked Example: One Worker, One Day
A groundworker's Tuesday:
| Tool | Vibration (m/s²) | Trigger time | Exposure points |
|---|---|---|---|
| Pneumatic breaker | 18 | 25 min | 270 |
| 9" angle grinder | 7 | 40 min | 65 |
| SDS hammer drill | 12 | 15 min | 72 |
| Total | 1h 20m | 407 |
Points per hour are calculated as 2 × (magnitude²), then scaled by trigger time. The total — 407 points — is over the ELV (400 points), even though no single tool got there on its own and the worker had hands-on tools for only 80 minutes all day. That's the multi-tool accumulation a daily log is built to catch. To do the maths quickly across a crew, use the free HAVS Exposure Calculator; for the conversion behind the numbers, see the HAVS points system explained.
Acting on What the Log Tells You
The log isn't paperwork for its own sake — it's a daily decision tool:
- Approaching the EAV (100 points): plan a rotation for tomorrow, or switch the worker to a lower-vibration tool. Don't wait for the threshold — a sensible internal alert is 80% of the EAV. (More on that in our daily EAV quick reference.)
- EAV reached (100 points): the regulations require you to introduce a programme of controls. See HAVS control measures for the options ranked by effectiveness.
- ELV reached (400 points): the worker must come off vibrating tools for the rest of the day. Investigate why, and record the action you took.
If a worker also reports tingling, numbness, or cold-weather blanching, that's separate from the points total and needs acting on in its own right — see what symptoms to watch for.
Making the Habit Stick
The first week of any new logging routine goes fine. The fourth week is where it dies. What keeps it alive:
- Make it short. If the daily log takes more than a couple of minutes per worker, it won't survive a busy day. Pre-fill the tool magnitudes so only trigger times change.
- Put it where the work is. A spreadsheet on an office laptop doesn't get updated next to a breaker. Use a paper sheet on a clipboard, or log on a phone where the worker is standing. (Generate a ready-to-print sheet with our free HAVS Log Sheet Template.)
- Total it the same day. A pile of un-totalled sheets is not a record you can act on — and not one HSE will accept as evidence you're managing exposure.
- One person owns it. "Everyone logs" usually means no one does. Name the supervisor or foreman responsible for the daily total.
The format matters less than the consistency. A paper sheet that gets filled in every day beats a sophisticated spreadsheet that gets updated once a month. For why a record that persists matters — and what HSE expects to see in it — read our HAVS register and records guide.
This is also exactly the friction HAVS·Log is built to remove: tool magnitudes pre-loaded, trigger times logged on a phone on site, points totalled automatically, and the EAV/ELV flagged before a worker goes over — so the daily record gets made without the daily admin.
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This guide is for general information only. It is not a substitute for professional health and safety advice.