Type 1, 2, 3 and 4 fire risk assessments explained

Where the four types come from

The Type 1 to Type 4 classification is not written into law. It comes from sector guidance for purpose-built blocks of flats — most influentially the guide "Fire safety in purpose-built blocks of flats", published in 2011 following the Lakanal House fire and widely treated as the definitive reference for the housing sector. The legal duty remains the one in the Regulatory Reform (Fire Safety) Order 2005: a suitable and sufficient assessment. The type labels are simply a shorthand the industry adopted for describing how far an assessment goes.

That shorthand matters commercially. A managing agent asking three assessors to quote for "a fire risk assessment" on a block of flats will get three very different prices if one is pricing a Type 1 and another a Type 3. Naming the type in the brief is the single easiest way to compare quotes fairly.

The two variables

Every type is a combination of two independent choices:

• Scope — common parts only (corridors, stairs, plant rooms, risers, bin stores), or common parts plus a sample of individual flats.
• Method — non-destructive, meaning visual inspection of what can be seen without opening anything up; or destructive, meaning targeted opening up of construction with a contractor present to make good afterwards.

Type 1 — common parts, non-destructive

The standard assessment, and the right answer for the large majority of blocks. The assessor inspects the common parts visually: escape routes, communal fire doors, signage, emergency lighting, the alarm and detection provision, housekeeping, and the visible elements of compartmentation such as service riser cupboards and obvious penetrations. Nothing is opened up.

A Type 1 satisfies the Fire Safety Order duty for the common parts and is what most managing agents commission annually. Its limitation is exactly its virtue: it reports on what can be seen, so it can flag suspicion about hidden construction but cannot resolve it.

Type 2 — common parts, destructive

Same scope as a Type 1, but with targeted opening up where the assessor has a specific, articulated doubt — a suspicion that a compartment wall does not reach the underside of the floor slab above, or that a riser has been penetrated by later cabling and never fire-stopped. It is sampling, not demolition: a small number of carefully chosen openings, agreed in advance, with a contractor to make good.

A Type 2 is a follow-on, not a starting point. It should be triggered by a finding in a Type 1 or by known construction risk, and the brief should state precisely what question the opening up is meant to answer.

Type 3 — common parts and flats, non-destructive

Extends the assessment inside a sample of flats, non-destructively, looking at the things that affect everyone else in the building: the condition and rating of the flat entrance door, means of escape from within the flat, and smoke detection provision. This goes beyond the Fire Safety Order — the inside of a flat is generally outside its scope — and touches the Housing Act 2004 regime instead, so the report needs to be clear about which duty it is speaking to.

A Type 3 is worth commissioning where risks inside flats plausibly affect the wider building: older stock with a history of unauthorised alterations, blocks where flat entrance doors have been replaced piecemeal by leaseholders, or where a stay-put strategy depends on compartmentation that has never been verified.

Type 4 — common parts and flats, destructive

The most comprehensive and the least common: destructive inspection in both common parts and a sample of flats. It is disruptive, expensive and usually needs vacant flats or very cooperative residents, so it is reserved for cases of serious concern — a building where the construction is genuinely unknown, where a stay-put strategy is under review, or where earlier assessments have found systemic compartmentation failures.

A Type 4 is a project, not a visit. Expect a scoping exercise, a contractor, resident liaison, and a programme rather than a day on site.

Choosing the right type

Start at Type 1 and escalate on evidence. Most blocks need a Type 1 reviewed regularly, with the review frequency recorded on the face of the report. Escalate to Type 2 when the assessor identifies a specific structural doubt; to Type 3 when the risk clearly sits inside the flats; to Type 4 only when the questions cannot be answered any other way.

Whichever type is commissioned, the report must state its own scope and limitations explicitly — what was inspected, what was not, and why. An assessment that does not say what it excluded is a liability rather than an asset. Recording that clearly is a discipline the PAS 79 methodology builds in, and one that fire risk assessment software can enforce rather than leave to the assessor’s memory.

Frequently asked questions