What Is Fire Stopping and Why Does It Matter?

Buildings are divided into fire compartments so that a fire can be held in one area long enough for people to escape and for firefighters to work. Fire stopping is what keeps those compartments intact where walls and floors are breached.

Where the gaps come from

Pipes, cables, ducts and trays pass through compartment walls and floors throughout a building. Each opening they create is a route for fire and smoke unless it is sealed with a suitable product.

Tested systems, not general products

Fire stopping only performs as intended when the product has been tested for that type of service, opening size and wall or floor construction. Using the wrong sealant, or the right one installed incorrectly, can leave a gap that looks finished but will not hold.

Common problems we find

Typical issues include unsealed holes left by later trades, expanding foam used where it is not supported by test evidence, mixed products in a single penetration, and missing labels or records.

Evidence matters

Every penetration we seal is photographed and logged in OneTrace with its location and the product used. That gives you a clear record of what was installed and where, rather than relying on what can be seen above a ceiling.

Where breaches come from

Almost every breach we find was created after the building was finished. Data cabling pulled through a ceiling void, a new condensate pipe from an air conditioning unit, a sprinkler retrofit, a fire alarm cable, a replacement extract duct. Each contractor made a hole, few sealed it properly and nobody recorded it. Over twenty years that adds up to hundreds of openings in walls that are supposed to hold fire for an hour.

Tested systems, not products

Fire stopping is not a tub of sealant. Each solution is tested as a system: a specific product or combination, in a specific substrate, around a specific service, with a maximum opening size and a defined installation method. A coated mineral wool batt with sealant may be tested for mixed services through a blockwork wall but not through plasterboard; an intumescent pipe collar is tested for a given pipe diameter and material. Using the right system means matching the test evidence to what is actually on site, which is why surveys record substrate, service and opening size for every breach.

Common mistakes

• Expanding polyurethane foam, which is not fire rated unless it is a tested intumescent foam used within its limits
• Sealing only one face of a wall
• Mineral wool packed into a hole with no coating or sealant
• Fire-rated sealant used in gaps wider than its tested limit
• Plastic pipes passed through with no collar or wrap
• Fire stopping damaged by later works and never reinstated

Labelling and records

A compliant fire stopping installation is labelled at the point of installation with the installer, the product system, the date and a reference, and that reference is linked to a photograph of the finished seal. Third-party certification schemes such as BM TRADA Q-Mark require this, and it is what allows a later inspector to verify the seal without opening it up.

Who should install it

Fire stopping looks simple and is routinely done badly by whichever trade made the hole. Third-party certified installers are audited on their training, their product knowledge and their installations, and they carry the test evidence for the systems they use. For higher-risk buildings the Building Safety Act’s competence requirements make that certification close to essential.

Frequently asked questions

Is fire stopping a legal requirement?

Yes. Building Regulations require compartmentation to be maintained through services, and the Fire Safety Order requires the Responsible Person to maintain it in existing buildings.

How long does fire stopping last?

Indefinitely if it is not disturbed. The risk is damage by later works, which is why periodic inspection and a record of every seal matter.

Can fire stopping be done while the building is occupied?

Yes. Most of our work is in occupied buildings, carried out area by area with dust containment and out of hours where needed.

Related service: Fire Stopping. Talk to us about what your building needs.

Read next: Compartmentation Surveys: What to Expect.