By FRA scope
A fire risk assessment covering the common parts plus a sample of flats, with destructive inspection in both. The deepest of the four FRA types, commissioned when significant compartmentation or construction concerns need physical verification across the whole building.
What it adds
Type 4 covers everything in Type 3 (common parts and a flat sample, non-destructive) plus targeted destructive inspection in both. Common-parts opening up follows the Type 2 pattern. In-flat opening up adds inspection of flat compartmentation (party walls and floors), service penetrations from the flat to common parts, and the fire-stopping around them.
When commissioned
Coordination
A Type 4 typically involves several specialist contractors: the competent FRA assessor leading the methodology, a building surveyor for the destructive opening-up, a fire-stopping contractor for any reinstatement found necessary, and (for HRBs) the building safety manager coordinating with the PAP. Resident communication is more substantial than for Type 3 because the access arrangements include destructive work in inspected flats.
The cost is materially higher than Type 1, 2 or 3. The work programme typically runs over weeks rather than days. The deliverable is correspondingly substantial: a full BS 9792-shaped report with destructive inspection records as supporting evidence.
In FRA Flow
In FRA Flow, a Type 4 assessment uses the workbench shape that combines Type 2's common-parts destructive records with Type 3's flat-sample records, with the addition of in-flat destructive records. The audit trail covers each opening: who carried it out, the wide-context and close-up photographs, the finding, the reinstatement record. Where the building is an HRB, the audit grade matches the safety-case-feeding evidence the PAP needs.
Common pitfalls
FAQ
A Type 4 is an FRA that includes destructive inspection. It still produces a BS 9792-shaped report. A full compartmentation survey is typically commissioned separately when the assessor has concluded the issues are widespread enough to need 100% coverage rather than sample-based verification.
Site work typically runs over weeks rather than days because of the destructive inspection coordination and resident access arrangements. The full report and reviewer sign-off cycle adds several weeks more on top.
The competent FRA assessor leads the methodology. A building surveyor or specialist fire-stopping contractor typically carries out the physical opening-up and reinstatement under the assessor's direction. The FRA records who did each part of the work.
Where the destructive inspection reveals findings that require urgent action, the FRA flags them in the action plan with the appropriate priority and target close-out timeframe. In serious cases the assessor may recommend an interim simultaneous evacuation strategy or a Waking Watch while remediation is planned.
Not at every periodic review. A Type 4 is typically a one-off or infrequent exercise commissioned when concerns have been raised. Most periodic reviews on HRBs run as Type 1 with an HRB-grade audit trail.
Book a 30-minute walkthrough sized to a Type 4 programme.
