Most buildings are designed to contain a fire in the place where it starts. Walls and floors are built to resist fire for a set period, so that a fire in one flat or one room does not reach the next before people escape and firefighters arrive. That design is called compartmentation. Fire stopping is the work that keeps it intact where services pass through.
Why breaches are so common
Every pipe, cable, duct and data line that passes through a fire-resisting wall or floor creates a hole. If the hole is not sealed with a tested fire stopping system, fire and smoke can pass straight through it. Over the life of a building, dozens of contractors may drill new holes for broadband, heating, alarms and refurbishments. Very few of them think about the compartment line.
Common problems include:
- holes left unsealed above suspended ceilings
- expanding foam used where a tested product was needed
- cables bundled through a single large opening
- missing cavity barriers in external walls and roof voids
- fire dampers that were never fitted or never tested.
How a compartmentation survey works
A surveyor opens up ceiling voids, risers, service cupboards and loft spaces and records every breach with a photograph, location reference and priority. The result is a register of defects and a set of marked-up plans that show where the compartment lines run and where they have failed.
What good fire stopping looks like
Good fire stopping uses a product that has been tested for the type of wall or floor and the type of service passing through it, installed exactly to the manufacturer's details. Each seal should be:
- photographed before and after
- labelled with a unique reference
- recorded with the product used and the installer's details.
Why the evidence matters
For higher-risk buildings, the Building Safety Regulator expects Accountable Persons to show evidence that compartmentation is intact. For every other building, the fire risk assessor will want to see it. A clear, photo-referenced record is the simplest way to prove that the work has been done properly.
This guide is general information about UK fire safety law and standards, not legal advice for a specific building. If you are unsure what applies to yours, ask us or a qualified adviser.