What is a compartmentation breach?
A compartmentation breach is a hole or unsealed penetration through a fire-resisting wall or floor that lets fire and smoke pass. Breaches are usually created by later works and are rarely reported by whoever made them.
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<img src="https://fireoptix.co.uk/glossary/breach/diagram.svg" alt="compartmentation breach — diagram from FireOptix" width="880" height="620" loading="lazy">
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<a href="https://fireoptix.co.uk/glossary/breach">What is a compartmentation breach?</a> — diagram by
<a href="https://fireoptix.co.uk">FireOptix</a>
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</figure>The defining feature of a breach is that it is invisible from the occupied side. A cable pulled through a wall above a ceiling looks like nothing from the corridor, and the wall keeps its appearance while losing its function.
Breaches are cumulative and they compound. One is a defect; a pattern across a building tells you the permit and supervision arrangements for contractors are not working, which is the thing that actually needs fixing.
In buildings relying on a stay put strategy, breaches are treated as urgent rather than routine, because the strategy itself assumes the compartmentation performs as designed.
In practice
A survey listing two hundred breaches in a residential block.
They cannot all be done at once and the list arrives with no prioritisation.
Breaches are not equal: one above a flat entrance door on an escape corridor matters differently from one in a plant room, and a remediation programme has to be risk-ordered to be deliverable.
An undifferentiated list produces paralysis, which is worse than a partial programme.
What goes wrong in practice
- Found during a survey and logged without an owner or a date to close it.
- Repaired without recording what was found, so the pattern is never visible.
- Contractors working above ceilings without a permit regime that requires reinstatement.