How the tiers connect
Tier 1 sets a baseline for a worker before or shortly after they start vibration-exposed work: a questionnaire covering symptoms and medical history. Tier 2 repeats a shorter version of that questionnaire at least annually for as long as they remain under surveillance. Both are non-clinical — HSE guidance describes them as suitable for a trained responsible person to administer, provided responses are reviewed by someone competent to spot when escalation is needed.
Where a Tier 1 or Tier 2 response indicates new or worsening symptoms, the worker moves to Tier 3: a hands-on clinical assessment by a qualified occupational health professional, checking grip strength and sensory function in more detail than a questionnaire allows. If Tier 3 findings need a formal diagnosis, Tier 4 is a doctor's examination, staging the condition against the modified Stockholm Workshop Scale and giving an opinion on fitness for continued vibration work. Tier 5 is optional further specialist or quantitative sensory testing, used where Tier 4 findings warrant it.
Where this comes from
This tiered structure is set out in HSE's statutory guidance document L140, not in the Control of Vibration at Work Regulations 2005 themselves — the Regulations require health surveillance (regulation 7) without specifying tiers, and HSE's own plain-English guide (INDG175) doesn't use the word "tier" at all. It's authoritative guidance rather than a legal requirement to use this exact terminology, and it's the structure this site's surveillance service follows.
Which tier does your workforce need?
Most workforces with controlled exposure and no reported symptoms sit at Tier 1–2. Escalation to Tier 3–4 happens on individual symptoms, not as a blanket policy — so a single workforce can legitimately have workers at different tiers at the same time.