Guide · Getting started - What a Noise Risk Assessment Actually Involves

A noise risk assessment is the document that tells you, in hard numbers, whether anyone on your site is exposed to noise above the regulatory action values — and if so, where, how much, and what has to change. It is the thing every other duty under the Control of Noise at Work Regulations 2005 hangs off: you cannot decide whether Hearing Protection Zones are needed, whether health surveillance is required, or what control measures are proportionate, without one in place and current.

Assessment, survey, or monitoring — which do you need?

These terms get used almost interchangeably, but they are not quite the same job:

• A noise risk assessment (sometimes “workplace noise assessment” or “occupational noise assessment”) is the full, documented exercise: measured exposure by role, the action values crossed, and the control measures that follow. This is the legal duty itself.
• A noise survey (or “industrial noise survey”) usually means the measurement sweep across the site — the raw readings an assessment is built from. A survey on its own, without the exposure calculation and written conclusions, is not a suitable and sufficient assessment.
• Noise monitoring (including “workplace noise monitoring” and “occupational noise monitoring”) is usually ongoing or repeated measurement — checking that exposure has not drifted since the last assessment, rather than a one-off exercise.
• Construction site noise monitoring is its own case: a project-based site with a changing layout and changing plant needs monitoring built around the programme of works, not a single fixed-site assessment. We cover sector-specific detail on the Construction sector page.

In practice, most sites that ask for a “noise survey” actually need the full assessment — it is worth confirming which one you are being quoted for before you book.

What the assessment has to establish

A suitable and sufficient noise risk assessment identifies daily personal noise exposure (L_EP,d) by role, not just a single site-average reading, and sets that against the three regulatory action values — 80, 85 and 87 dB(A). Where those thresholds are crossed, it has to identify what controls are proportionate, from engineering controls through to Hearing Protection Zones. The full step-by-step process — what actually happens on the day, and what you get back — is covered in What Happens in a Noise Assessment, and the legal basis for all of it is set out in the Regulations, in plain English.

A short example

A press shop running three stamping lines on one shift is a typical case: readings taken machine by machine and role by role show operators standing closest to the presses crossing 87 dB(A), while packing staff ten metres away sit comfortably under 80 dB(A) — two very different risk pictures on one floor, which is exactly why a single site-average number is not a suitable and sufficient assessment on its own. We walk through a full worked example, hotspot by hotspot, in Mapping Noise in a Press Shop, and eight more real site assessments — aluminium machining, a brewery, marine engineering and others — in our case studies.

Who can carry one out

The Regulations require a “competent person” — not just anyone with a borrowed sound level meter. What that competence actually means in practice, and the questions worth asking before you book an assessment, are covered in Who Can Carry Out Your Assessment?.

An assessment is a snapshot, not a certificate

A noise risk assessment is only accurate for as long as the site it describes stays the same. New machinery, a changed shift pattern or a layout move can all quietly invalidate an assessment that was correct the day it was written — see How Often to Reassess for what actually triggers a re-check, rather than relying on a fixed expiry date.