PAS 79 methodology: how a structured fire risk assessment is carried out

PAS 79 is the British Standards Institution's published methodology setting out how a fire risk assessment should be structured and carried out. It isn't itself a legal requirement, but it is the recognised, industry-standard framework that a competent assessment is expected to follow — and it gives clients a way of judging whether an assessment they've received is actually fit for purpose.

Since 2020 it has not been a single document. It was split into two parts: PAS 79-1 for premises other than housing, and PAS 79-2 for housing. The housing part has since been withdrawn and replaced — see Where PAS 79 stands today below. Material that refers to "PAS 79" without a part number generally predates the split and should be read with that in mind.

Why a standard methodology matters

Fire risk assessment is a judgement-based exercise — two competent assessors looking at the same building should reach broadly the same conclusions, but only if they're working to a consistent framework. Without one, the quality and thoroughness of an assessment depends entirely on the individual assessor's own habits, which makes it very difficult for a duty holder to know whether they're getting a genuinely thorough assessment or a superficial one. PAS 79 exists to close that gap.

The core structure

PAS 79 sets out a systematic sequence: identifying fire hazards (sources of ignition, fuel, and oxygen), identifying the people at risk and how vulnerable they are, evaluating the risk arising from those hazards, and considering the adequacy of existing fire precautions — means of escape, fire detection and warning, fire-fighting equipment, and the management of fire safety over time. The output is a structured record of significant findings, not a free-form narrative, which is what makes assessments carried out to PAS 79 comparable and auditable.

Risk rating, not just risk identification

One of the more important aspects of PAS 79 is that it doesn't stop at listing hazards — it provides a framework for rating the overall level of fire risk in a building (commonly expressed in bands such as trivial, tolerable, moderate, substantial, or intolerable), and for rating individual findings by priority. This is what allows an action plan to be genuinely prioritised, rather than presenting every finding as equally urgent.

Where PAS 79 stands today

This matters more than it might sound, because the two parts no longer share a status.

PAS 79-1:2020, covering premises other than housing, remains current. It is the methodology behind most non-domestic fire risk assessments carried out in the UK.

PAS 79-2:2020, covering housing, does not. BSI suspended it in March 2021 and confirmed its withdrawal that August, principally because expectations around the evacuation of disabled and vulnerable residents had moved on. It was replaced in August 2025 by BS 9792:2025, a full revision published as a British Standard rather than a PAS.

The practical consequence: for a workplace, school, shop or other non-domestic building, PAS 79-1 is still the reference. For a block of flats or other housing, it is BS 9792, and a housing assessment still citing PAS 79-2 is working from a methodology that no longer stands — not automatically invalid, but worth reviewing, particularly on anything touching evacuation of disabled and vulnerable residents.

What this means for you as a client

When you commission a fire risk assessment, asking which published methodology it follows — and whether that methodology is the right one for the building — is a reasonable and useful question — it tells you the assessor is following a recognised, structured methodology rather than an informal walk-round. It also means the resulting report should give you a clear risk rating for the building as a whole, not just a list of individual issues, and a genuinely prioritised set of actions rather than an undifferentiated checklist.

In practice

Our fire risk assessments are informed by recognised guidance — PAS 79-1 for non-domestic premises and BS 9792 for housing, applied as appropriate to the premises and scope — from initial hazard identification through to a risk-rated, prioritised action plan. A structured approach is what turns an assessment into something you can actually act on, rather than a document that sits on a shelf.