Glossary
Type 4 fire risk assessment.
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.
What Type 4 includes.
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 Type 4 is appropriate.
Type 4 is typically commissioned when previous lighter assessments have identified a concern severe enough that the dutyholder cannot proceed without verification. It is also appropriate after a known fire incident (to verify the actual performance of compartmentation), after major refurbishment of a residential block where records are incomplete, or as part of a building safety case investigation under the Building Safety Act 2022 for an HRB where compartmentation evidence is critical.