Types of Fire Risk Assessment: Type 1 to Type 4 Explained
By the DC Fire & Security engineering team — installing and maintaining fire and security systems since 2010. Updated June 2026.
Quick answer
The four FRA types apply to residential blocks: Type 1 (common parts, non-destructive — the default), Type 2 (common parts, destructive sampling — where construction defects are suspected), Type 3 (adds flats, non-destructive), Type 4 (common parts and flats, destructive — the deepest look). Most blocks need Type 1 routinely, escalating types when findings or history demand. Workplaces use standard (untyped) FRAs.
The four types, precisely
The typing applies to residential blocks (PAS 79-2 territory and the housing guidance lineage); workplace FRAs are simply FRAs — scoped by premises, not typed. Type 2/4's destructive sampling overlaps compartmentation survey practice — coordinated commissioning (one opening-up programme serving both) is the procurement win our combined surveys deliver.
| Type | Scope | Destructive? | When commissioned |
|---|---|---|---|
| Type 1 | Common parts only | No | The routine default for blocks — regular cycle |
| Type 2 | Common parts | Yes — sampling opens construction | Defect suspicion: compartmentation doubts, cladding-era scrutiny, pre-purchase depth |
| Type 3 | Common parts + sample flats | No | Concerns spanning demise lines: alarms in flats, flat entrance doors, conversion histories |
| Type 4 | Common parts + flats | Yes | The full forensic: serious defect history, post-incident, safety-case evidence |
Choosing the type your block needs
Decision logic agents and RMCs can apply: routine cycles on maintained purpose-built blocks → Type 1 (annual-to-triennial per risk profile, the review-frequency wisdom); conversion-era buildings, unexplained alarm histories, or flat-door/in-flat provision questions → Type 3's sampling across demise lines; construction-integrity doubts (works history, cladding adjacency, survey findings, insurer/lender pressure) → Type 2's opening-up; and accumulation of the above, safety-case building under the Building Safety Act, or post-incident reconstruction → Type 4. Escalation is evidence-led: Type 1 findings naming suspicions ('riser penetrations unverifiable — recommend Type 2 sampling') are the system working. What typing never changes: the legal requirement is suitable-and-sufficient assessment — typing calibrates sufficiency to building reality (the responsible-person duties guide carries the legal frame).
Costs, access and coordination
Pricing shape by type: Type 1 from the standard bands (£300–£700 typical small-mid blocks); Type 3 adds flat-sampling logistics (appointment cycles per the access realities — £500–£1,200 ranges); Types 2/4 price with opening-up and making-good (£1,000–£3,000+ by sampling scope — coordinated with compartmentation survey economics where both are wanted; the combined programmes we quote merge them). Access choreography dominates elapsed time on 3/4 (resident notices, sampling consent, the best-endeavours documentation habits), and making-good standards decide reputations (Type 2/4 firms are judged by their patching — photograph everything, ours included). Output expectations rise with type: action plans referencing opened evidence, photographic schedules, and safety-case-grade documentation at Type 4 (the golden-thread expectations from our Building Safety Act work). Commission types deliberately, escalate on evidence, and coordinate intrusive work once — blocks that drift into serial partial surveys pay for the same risers thrice.
Related guides
Frequently Asked Questions
Our managing agent ordered 'an FRA' — which type did we get?
How often should Type 1 FRAs repeat?
Is Type 4 required for Building Safety Act safety cases?
Can flats refuse access for Type 3/4 sampling?
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