For responsible persons and managing agents
Fire Compartmentation Survey: What It Checks, What It Finds and How It Is Fixed
Sviatoslav JerdetchiiCEO & Founder of Craftex. Updated , 7 min read
The short answer
A fire compartmentation survey inspects every fire-resisting wall, floor, door and service penetration that should stop fire and smoke spreading, and lists each breach with its location so it can be fire stopped or repaired.
- It is usually triggered by the fire risk assessment.
- It opens voids, risers and ceilings that an assessment only samples.
- The report becomes the remediation scope.
A fire compartmentation survey checks every wall, floor, door and service opening meant to hold back fire and smoke. It records each gap with its location. Your fire risk assessment may have called for one. This guide shows what it covers and what follows. For the repairs, our fire stopping contractors work from your report.
This guide is for responsible persons, managing agents, facilities managers and housing providers. We are a London contractor, so it follows the survey past the report, to the repairs, the access and the paperwork. Holding a report now? Get a free remediation scope and cost plan.
Fire stopping, passive fire protection and compartmentation
Three terms get used as if they meant the same thing. They do not, and the difference decides who you hire and what you ask them to price.
| Term | What it means | Examples |
|---|---|---|
| Compartmentation | Dividing a building into fire-resisting sections so fire and smoke stay where they start | Compartment walls and floors, protected shafts, cavity barriers |
| Passive fire protection | Fire protection built into the structure that works without being switched on | Fire-resisting walls and floors, fire doors, dampers, protected steel |
| Fire stopping | Seals that close joints and openings in fire-separating elements | Collars on plastic pipes, sealed cable penetrations, linear joint seals |
Approved Document B defines compartmentation as a building or part of a building constructed to prevent fire spreading to or from another part. It adds that effective compartmentation needs continuous fire resistance at every join, and openings that do not weaken it.
Fire stopping is the detail that most often fails. The guidance says every joint, imperfect fit and opening for services through a fire-separating element should be sealed. Passive fire protection is the wider family: the walls, floors, doors, dampers and seals that work together.
What a fire compartmentation survey checks
A survey starts at a desk. The surveyor reads the fire strategy and the drawings to find where the compartment lines should run. Then the building is walked and each line is followed.
Non-intrusive and intrusive inspection
The Fire Protection Association describes its survey as typically non-destructive. The surveyor looks from ceiling hatches, risers and voids, and does not break into finished surfaces. Where a defect points to hidden problems, a further intrusive survey can open the construction up. Scopes differ between firms, so ask what is opened and who makes good.
The areas it covers
The typical scope runs from the roof void to the basement. It includes:
- Roof voids, floor voids and ceiling voids
- Risers, shafts and service cupboards
- Plant rooms and basements
- Fire doors, frames, seals and closers
- Dampers where ducts pass through fire lines
- Walls and floors that form the compartment lines
The report should give annotated plans of each floor with the compartment lines marked. Each breach should have an ID, a location, a photograph and a suggested repair detail. A priority rating lets you plan the repairs in order.
If your survey says repairs are needed, our fire stopping contractors can scope and price them from the report.
When you need a compartmentation survey
The law does not use the term. The Fire Safety Order says the responsible person must make a suitable and sufficient assessment of fire risks (article 9). It also requires the fire precautions to be maintained in efficient working order (article 17). A survey is how many owners show both are true for the building's fire lines.
Four triggers are common:
- The fire risk assessment recommends one. It samples the building, so it flags where a fuller check is needed.
- A refurbishment is planned. Opening ceilings and risers is the moment to find breaches. Our guide to building regulations for office fit-out covers what a fit-out must keep intact.
- Use changes. A commercial to residential conversion creates new compartment lines that must be designed and built.
- Many trades have been through the walls. Every cable, pipe and duct added over the years is a possible gap.
The Fire Safety Act 2021 widened the Order in England from 16 May 2022. In a building with two or more sets of domestic premises it now covers the structure, external walls and common parts. It also covers the doors between flats and the common parts. For the external walls, see our guide to FRAEW and PAS 9980.
Common defects and how they are fixed
Surveys find the same defects again and again. Each needs a different repair and a different piece of evidence.
- Unsealed service penetrations. Pipes, cables and ducts pass through a wall or floor with a gap around them. The fix is a tested sealing system or approved fire-stopping material. The evidence is a photograph of each seal and its product data.
- Missing cavity barriers. Concealed voids above ceilings and inside walls need barriers to stop smoke and flame travelling. The fix is fitting barriers to the guidance. The evidence is a photograph before the void is closed.
- Damaged or poorly fitting fire doors. Gaps, missing seals, broken closers and wrong hardware stop a door doing its job. The fix is repair or replacement as a complete doorset. The evidence is a door schedule and inspection record.
- Missing or faulty dampers. A duct that crosses a fire line needs a damper or fire-resisting duct. The fix is a correctly fitted damper with fire-stopping around it. The evidence is the installation record.
- Unprotected structural steel. Steel that holds up a compartment floor may need coating or boarding. The fix is protection to the specified rating. The evidence is a record of the coating or board system.
Approved Document B says openings for services should be as few and as small as practicable. It also names proprietary tested systems as an accepted route. The right seal depends on the wall, the service and the movement expected.
Craftex has completed a range of both small and large-scale projects on our commercial property with exceptional precision and quality. Dmitriy consistently delivers courteous, prompt service and has shown great flexibility in accommodating last-minute changes to plans and timelines. I highly recommend Craftex for their professionalism and outstanding workmanship.
Fixing the defects with the building occupied
Most blocks, offices and hotels stay in use while the repairs happen. That shapes the programme more than the fire stopping itself.
How the works are run
Works are sequenced floor by floor, so the building loses as little as possible at a time. Ceiling tiles, riser doors and flat visits are booked in advance. Every opening is made safe at the end of each shift. Each repair is photographed before it is closed up.
At Kensington Olympia we rebuilt a 400 sq m penthouse in 12 weeks while the building stayed fully occupied. At Portsoken House in Aldgate we rebuilt the reception at night and at weekends, while the other floors stayed let. Neither was a fire-stopping project. We carry £10M public and £10M employers' liability cover.
Approval in a higher-risk building
A higher-risk building is at least 7 storeys or 18 m with at least two residential units. Work to an existing one needs Building Safety Regulator approval before it starts. The gov.uk guidance lists work involving passive fire safety measures, and work on common parts, as Category A. Plan the approval time into your programme.
Fire stopping regulations and duties
Four sets of rules sit behind the survey. Each answers a different question.
| Rule | What it requires |
|---|---|
| Fire Safety Order 2005, articles 9 and 17 | A suitable fire risk assessment, kept up to date, and fire precautions maintained in working order |
| Fire Safety Act 2021 | Extends the Order to structure, external walls, common parts and flat doors in multi-dwelling buildings |
| Fire Safety (England) Regulations 2022 | Fire door checks and resident information in buildings with a top storey above 11 m |
| Approved Document B | Guidance on compartmentation, cavity barriers and fire-stopping for new work |
For fire doors, the 2022 regulations set the cycle. Communal fire doors are checked at least every 3 months. Responsible persons must use best endeavours to check flat entrance doors at least every 12 months. New residents must be given fire door information, and all residents reminded at least yearly.
Who pays
Government guidance lists replacing inadequate fire doors and fixing missing compartmentation as non-cladding defects. For qualifying leaseholders the contribution is normally capped at £10,000, or £15,000 in Greater London. Costs above the cap fall to the owner. Where costs can be recharged, the Section 20 consultation applies, so plan it before you instruct works.
Use this list before you appoint. Send us your survey and get a free remediation scope and cost plan. Already have a quote? Send it to us. We'll beat it. Our fire stopping contractors price from your report.
- A fire risk assessment that is in date and names the compartmentation actions
- A survey report with every breach located on a plan, photographed and ranked
- Fire strategy and drawings made available, so the repair matches the original design
- Product data and the fixing method agreed for each type of opening
- Fire door checks scheduled: 3-monthly communal, 12-monthly flat entrance
- Access plan for residents, with notice periods and make-safe at the end of each shift
- Approval route confirmed if the building is higher-risk
- Photographic evidence and product records handed over for the building's fire file
