What is the difference between fire stopping and fireproofing?

Fire stopping in plain terms

A fire-rated wall or floor only works if it has no holes in it. Every cable, pipe, duct and joint that passes through is a hole, and each one has to be closed with a product tested for that job. That closing is fire stopping.

Typical materials are intumescent sealant, fire-rated collars and wraps on plastic pipes, mortar and board for larger openings, and batts or pillows for cable bundles. Which one is right depends on what goes through the opening, the wall or floor it passes through and how long the wall has to last. A sealant that is fine on a pipe through a masonry wall can be wrong for a cable tray through a plasterboard partition.

The aim is to keep the compartment intact, so a fire in one flat, room or floor stays there long enough for people to leave. Our page on fire compartmentation explains the idea, and passive fire protection shows where fire stopping fits among fire doors, cavity barriers and structural protection.

Fireproofing in plain terms

Fireproofing is the word people use most often when they mean protecting the building structure. The classic example is steel, which loses strength in a fire, so it is wrapped in boards or coated in an intumescent paint that swells up when heated. Timber and concrete may also be protected or detailed to resist fire for a set time.

It is a loose word. Nothing is truly fireproof, and a product or system is tested and given a period of resistance, such as 30, 60 or 120 minutes. In the trade you will hear fire protection or fire resistance used instead, and a specification will name the system and the period, not just say fireproofed.

Side by side

Why they get confused

Both are part of passive fire protection, so they get described with the same words. A fire risk assessment may say the building needs more fireproofing when the real finding is gaps around services, or the other way round. If you read that line in a report, ask which one was meant and where, because the work and the contractor are different.

On site, the common faults we see on fire stopping are holes left after cabling or plumbing work, the wrong product used for the service, and old fire stopping disturbed by later trades. Those faults sit in risers, above ceilings and around service penetrations in corridors, where nobody looks until a survey does.

Who does each job

Fire stopping is carried out by our third-party certificated fire stopping contractors, working to the tested system for each opening. Structural fire protection is a separate specialist trade, usually designed with the building's structural engineer. If you are not sure which you need, start with a survey. Our page on a fire stopping survey explains what it covers, and a compartmentation survey looks at the building as a whole.