The four types of fire risk assessment, and which one your block needs

Not every fire risk assessment looks at the same things. Two assessors can visit the same block, produce two very different reports, and both be doing their job. The difference is the type of assessment they were asked to carry out. If you instruct one without knowing which, you can pay for a document that never looks at the thing you were worried about.

The four types come from the way the industry has long described the scope of a fire risk assessment in blocks of flats. They run from a visual check of the common parts to a full opening-up of the construction. Here is what each one actually covers.

Type 1: the common parts, without opening up

A Type 1 is the standard assessment for most blocks of flats. The assessor looks at the common parts, the escape routes, the fire doors you can see, the alarm and lighting, and the general fire precautions. They do not go inside flats and they do not open up the construction to check what is behind the plasterboard. For a great many buildings, kept up to date, a Type 1 is proportionate and appropriate.

Type 2: the common parts, with some opening up

A Type 2 is a Type 1 plus destructive inspection in a sample of places. The assessor opens up parts of the structure to check compartmentation, cavity barriers and fire stopping where there is reason to believe there may be a problem. You would commission this after a fire, during major works, or where the history of the building suggests the hidden construction cannot be taken on trust.

Type 3: common parts and flats, without opening up

A Type 3 widens the scope to include a sample of the flats themselves, looking at flat entrance doors, the internal escape arrangements and the general fire precautions inside dwellings, but without destructive inspection. It is the assessment to reach for when the concern is not the structure but the way individual flats and their front doors are performing.

Type 4: common parts and flats, with opening up

A Type 4 is the fullest of the four: a Type 3 plus destructive inspection in both the common parts and a sample of flats. It is intrusive, more expensive and more disruptive, and it is reserved for buildings where there is real doubt about both the construction and the dwellings. You do not start here. You arrive here when the lower types have told you that you cannot see enough.

A new standard now sits behind all of this

Until recently the four types were described in guidance rather than a formal standard. That changed with BS 9792:2025, a British Standard published in August 2025 that gives a code of practice for fire risk assessment in housing, including blocks of flats, HMOs and specialised housing. It names freeholders, managing agents and management companies directly. It replaced the withdrawn PAS 79-2:2020. The four types have not gone away, but there is now a recognised standard for how a housing assessment should be scoped and recorded.

The point is matching the type to the question

The mistake is not choosing the wrong type. The mistake is not choosing at all, and accepting whatever lands. If you are worried about cladding or hidden fire stopping, a visual Type 1 will never reach it, however good the assessor. If your concern is flat front doors, you need the flats in scope. An independent adviser earns their fee here by asking what you are actually trying to find out, then specifying the assessment that answers it.

That is the part OmniFire does before a single assessor is instructed. We are not the ones who carry out the intrusive survey or fit the fire doors, so we have no reason to talk you into a bigger assessment than your building needs, or a smaller one than it deserves.

If you are not sure which type of assessment your block has had, or should have, send me the address and I will tell you what fits. Email s.coogan@omnifire.co.uk.