Type 1, 2, 3 & 4 Fire Risk Assessments Explained
Not all fire risk assessments are the same. For residential buildings, they are categorised into four types — from a non-intrusive look at the common parts to a full intrusive inspection of flats. This guide explains each type and how to know which one your building needs.
In short: Type 1 = common parts, non-intrusive (the standard). Type 2 = common parts, intrusive. Type 3 = common parts + flats, non-intrusive. Type 4 = common parts + flats, intrusive (the most thorough).
Why Are There Different Types?
The four-type classification applies to fire risk assessments of residential blocks of flats and reflects two variables: scope (common parts only, or common parts plus a sample of flats) and method (non-intrusive visual inspection, or intrusive inspection that opens up construction). Combining these gives four levels of assessment, each suited to a different level of risk and uncertainty about the building.
The Four Types of Fire Risk Assessment
The standard and most common assessment. A visual inspection of the common parts — corridors, stairs, plant rooms, risers — checking fire doors, escape routes, signage and visible compartmentation. No opening up of construction. The baseline for most blocks of flats.
As Type 1, but with limited opening up of construction in the common parts to inspect concealed compartmentation, cavity barriers and fire stopping. Usually commissioned where there are specific concerns about hidden construction in the common areas.
Covers the common parts plus a non-intrusive inspection of a sample of individual flats — looking at flat entrance doors, internal fire precautions and means of escape within dwellings. More thorough than Type 1 but still without destructive work.
The most comprehensive assessment. Intrusive inspection of both the common parts and a sample of flats, opening up construction to verify compartmentation throughout. Reserved for higher-risk buildings or where serious concerns have been raised.
Quick Comparison
| Type | Common Parts | Flats Sampled | Intrusive |
|---|---|---|---|
| Type 1 | ✓ | ✗ | ✗ |
| Type 2 | ✓ | ✗ | ✓ |
| Type 3 | ✓ | ✓ | ✗ |
| Type 4 | ✓ | ✓ | ✓ |
Which Type Does Your Building Need?
- Most blocks of flats need a Type 1 assessment as a minimum, reviewed regularly.
- A Type 3 may be appropriate where there are concerns about fire safety within flats or means of escape from dwellings.
- A Type 2 or Type 4 is commissioned where construction is unknown or compartmentation is in doubt — for example, older buildings or after defects are found.
- The right choice depends on the building’s age, construction, risk profile and history — a competent assessor will recommend the appropriate type.
Whichever type you need, it must be carried out by a competent person. Learn more about our fire risk assessment service and why accreditation matters when choosing an assessor.
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Frequently Asked Questions
What are the four types of fire risk assessment?
For residential buildings, fire risk assessments are categorised into four types. Type 1 is a non-intrusive assessment of common parts only. Type 2 is intrusive (destructive) and inspects the construction of common parts. Type 3 covers common parts plus a sample of flats, non-intrusively. Type 4 is the most thorough — intrusive inspection of both common parts and a sample of flats.
What is a Type 1 fire risk assessment?
A Type 1 fire risk assessment is the standard, non-intrusive assessment of the common parts of a residential building (corridors, stairs, plant rooms). It checks fire doors, escape routes, signage, and visible elements of compartmentation without opening up the construction. It is the most common type and the baseline expectation for most blocks of flats.
What is the difference between a Type 1 and Type 4 fire risk assessment?
A Type 1 assessment is non-intrusive and covers only the common parts. A Type 4 assessment is the most comprehensive: it is intrusive (involving opening up of construction) and covers both the common parts and a sample of individual flats. Type 4 is usually carried out when serious concerns about construction or compartmentation have been identified, or for higher-risk buildings.
Which type of fire risk assessment do I need?
Most residential buildings need a Type 1 assessment as a minimum, reviewed regularly. A Type 3 or Type 4 may be recommended where there are concerns about fire spread between flats, unknown construction, or following a serious incident. The right type depends on the building’s age, construction, risk profile and history — a competent assessor will advise which is appropriate.
Are Type 2 and Type 4 fire risk assessments destructive?
Yes. Type 2 and Type 4 assessments are intrusive, meaning small areas of construction are opened up (for example, sections of ceiling or wall) to inspect concealed compartmentation, cavity barriers and fire stopping. This is why they are usually commissioned only when there is a specific reason to verify hidden construction, and they require making good afterwards.
How often should a fire risk assessment be reviewed?
A fire risk assessment must be reviewed regularly and kept up to date. Best practice is an annual review, with a full reassessment typically every one to three years depending on the building’s risk, and immediately after significant changes, building works, or a fire-related incident.
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Fyrup's accredited assessors carry out Type 1 to Type 4 fire risk assessments across London, helping you choose the right level for your building and meet your legal duties.