Hand Arm Vibration Testing: When and How to Monitor Your Workforce
Two Types of "Testing" — Know Which You Need
When employers search for "hand arm vibration testing," they're usually looking for one of two things:
- Exposure assessment — measuring or calculating how much vibration workers are exposed to (daily A(8) exposure)
- Health surveillance — medical screening to detect early signs of HAVS in exposed workers
Both are required under the Control of Vibration at Work Regulations 2005, but they serve different purposes and follow different processes. This guide covers both.
Exposure Assessment: Measuring What Workers Are Exposed To
What to measure
You need the daily A(8) exposure for each worker who uses vibrating tools. This requires two inputs per tool:
- Vibration magnitude (m/s²) — from manufacturer data or the HSE vibration database
- Trigger time — actual hands-on-tool duration per shift
Three approaches to exposure assessment
Estimation from published data (most common for small firms): Use the manufacturer's declared vibration value and estimate trigger times from observation. This is what HSE expects most employers to do. It doesn't require specialised equipment — just the tool data and honest trigger time estimates.
Calculate daily exposure using the points method: (magnitude ÷ 2.5)² × 100 = points per hour, multiplied by trigger time. Use the free HAVS Exposure Calculator to run the maths.
Direct measurement with vibration meters: An accelerometer is attached to the tool handle and measures actual vibration during use. This is more accurate but requires specialist equipment and expertise. It's typically done by occupational hygienists — not by the employer directly.
When to use direct measurement:
- When manufacturer data is unavailable or unreliable
- When the tool has been modified or is heavily worn
- When you need to verify that control measures have reduced vibration
- When HSE disputes your exposure estimates
Dosimetry (wearable monitoring): Wrist-mounted vibration dosimeters measure cumulative exposure throughout the shift. Enterprise solutions using wrist-mounted vibration dosimeters use this approach. It's the most accurate method but requires hardware investment — typically viable only for larger operations.
How often to assess
- At baseline: When you first identify that workers use vibrating tools
- When tools change: New tools, worn tools, different tasks
- When exposure patterns change: Different shift lengths, new projects, different work mix
- After implementing controls: Verify that changes actually reduced exposure
- At least annually: Even if nothing has changed, reassess to confirm
Health Surveillance: Detecting HAVS Early
When health surveillance is required
Health surveillance is mandatory for any worker whose daily exposure regularly reaches or exceeds the EAV (2.5 m/s² A(8) / 100 points), or who is otherwise at risk of developing HAVS.
The tier system
| Tier | What happens | Who does it | When |
|---|---|---|---|
| 1 | Pre-employment questionnaire about prior vibration exposure and existing symptoms | Worker (self-assessment) | Before starting vibrating tool work |
| 2 | Annual questionnaire — any new symptoms since last check? | Trained supervisor or H&S coordinator | Annually |
| 3 | Standardised tests: grip strength, dexterity, sensory perception, Raynaud's screening | Occupational health nurse/technician | When Tier 2 flags symptoms |
| 4 | Full clinical assessment and formal staging | Occupational health doctor | When Tier 3 confirms possible HAVS |
| 5 | Specialist diagnosis and management | Consultant | Complex or disputed cases |
What triggers escalation
Escalate from routine Tier 2 screening to Tier 3 assessment when a worker reports:
- Tingling or numbness in fingers that persists after work
- White finger episodes (blanching triggered by cold)
- Difficulty handling small objects
- Reduced grip strength
- Pain or aching in hands, wrists, or forearms
Don't wait for the annual screening. If a worker reports symptoms at any time, arrange a Tier 3 assessment promptly.
What happens after a HAVS finding
If a worker is diagnosed with HAVS or shows early symptoms:
- Reduce their exposure — move them to tasks with lower or no vibration, at least temporarily
- Review the risk assessment — the controls weren't sufficient
- Review other workers — if one worker has symptoms, others with similar exposure may be affected
- Continue health surveillance — more frequently if symptoms are progressing
- Record everything — the assessment findings, your response, and the follow-up plan. Health surveillance records must be kept for 40 years.
Ongoing Monitoring: Making It Sustainable
The biggest challenge isn't the initial assessment — it's keeping it going. Month 1 is diligent. Month 6, the log sheets aren't being filled in.
For small contractors (2–50 workers):
- Daily: Record trigger times and calculate exposure points. Even a rough estimate is better than nothing. Use our HAVS Log Sheet Template for a structured format.
- Annually: Run Tier 2 health surveillance screening for all exposed workers. Calendar it — treat it like a vehicle MOT.
- When things change: New tools, new projects, new workers — reassess exposure levels.
- Ongoing: Track trends. If a worker's exposure is consistently at 80%+ of the EAV, they need closer monitoring.
Purpose-built tools like HAVS·Log automate the daily calculations and flag when workers approach thresholds — replacing the manual tracking that most small firms struggle to maintain.
Sources
This guide is for general information only. It is not a substitute for professional health and safety advice.