What Is a
Compartmentation Survey?

Published 12 April 2026 • DE Fire Compliance • 6 min read

A compartmentation survey is a detailed inspection of the fire barriers within a building — the walls, floors, ceilings, doors, and fire stopping that divide the building into separate fire-resistant compartments. The purpose is to check that these barriers are intact and will contain fire and smoke for their rated period (typically 30 or 60 minutes).

If compartmentation fails during a fire, smoke and flame can spread rapidly through the building, cutting off escape routes and putting lives at risk. That’s why compartmentation surveys are a critical part of any fire risk assessment.

How Does Compartmentation Work?

Every building designed to comply with UK fire safety regulations is divided into fire compartments. These are enclosed areas bounded by fire-resistant construction — walls, floors, and ceilings that have a defined fire resistance rating.

The principle is simple: if a fire starts in one compartment, the fire-resistant barriers should prevent it from spreading to adjacent compartments for a specified period. This gives occupants time to escape and fire services time to respond.

Compartmentation relies on several elements working together:

• Fire-resistant walls and floors — constructed to achieve a fire resistance rating (e.g., 60 minutes)
• Fire doors — rated door assemblies that maintain the integrity of compartment walls where openings are needed
• Fire stopping — seals and fillers around service penetrations (pipes, cables, ducts) that pass through compartment barriers
• Cavity barriers — barriers within ceiling voids, wall cavities, and floor voids that prevent fire spreading through hidden routes
• Dampers — devices within ductwork that close automatically in a fire to prevent spread through ventilation systems

If any one of these elements is missing, damaged, or incorrectly installed, the entire compartment line can be compromised.

What Does a Compartmentation Survey Involve?

A compartmentation survey is typically carried out by a specialist fire stopping surveyor or passive fire protection professional. The survey covers:

1. Desktop review

The surveyor reviews building plans, fire strategy documents, and any previous fire risk assessments to understand the intended compartmentation layout.

2. Physical inspection

The surveyor inspects the fire barriers throughout the building, including:

• Compartment walls — checking for breaches, damage, or unauthorised openings
• Service penetrations — inspecting every pipe, cable, and duct that passes through a compartment wall or floor for correct fire stopping
• Ceiling and floor voids — checking that cavity barriers are present and correctly installed
• Fire doors — assessing condition, gaps, seals, closers, and signage (this can be done separately as a dedicated fire door inspection)
• Risers and shafts — checking vertical service risers for fire stopping and compartmentation integrity
• Roof spaces — inspecting fire barriers where the building adjoins party walls or changes construction

3. Photographic evidence

Every defect is photographed and located within the building. Good practice is to record both the defect and its location in relation to the building layout.

4. Reporting

The surveyor produces a detailed report listing all findings, categorised by severity, with photographic evidence and recommended remedial actions. The report should clearly identify which compartment lines are compromised and what work is needed to restore them.

Who Needs a Compartmentation Survey?

A compartmentation survey is recommended for:

• Residential blocks of flats — particularly those with communal areas, risers, and flat entrance fire doors
• Higher-risk buildings — buildings over 18m or 7+ storeys (these have specific requirements under the Building Safety Act 2022)
• Care homes and healthcare facilities — where vulnerable occupants depend on compartmentation for their safety
• Commercial buildings — offices, retail, warehouses, and mixed-use buildings
• Buildings undergoing refurbishment — renovation works frequently breach compartmentation without proper reinstatement
• Buildings that have never been surveyed — if you don’t know the condition of your compartmentation, a survey is the only way to find out

Common finding: Buildings that have been refurbished, had new services installed, or changed use are the most likely to have compromised compartmentation. Trades that install plumbing, electrics, or data cabling frequently penetrate compartment walls and floors without reinstating the fire stopping.

Common Defects Found in Compartmentation Surveys

The most common issues found during compartmentation surveys include:

• Missing fire stopping around service penetrations — pipes, cables, and conduits passing through compartment walls with no fire sealant
• Incorrect fire stopping products — builders’ foam or generic sealant used instead of tested, certified fire stopping products
• Holes in compartment walls — left after removed services, abandoned cables, or building works
• Missing cavity barriers — particularly in ceiling voids above corridors and in vertical risers
• Defective fire doors — see our guide to failed fire door inspections
• Breached fire walls during renovation — works carried out without fire stopping reinstatement

Compartmentation Survey vs. Fire Door Inspection

A fire door inspection and a compartmentation survey are related but different:

• Fire door inspection: Focuses specifically on the fire door assemblies — the door leaf, frame, seals, closer, gaps, and hardware. Assessed against BS 8214:2016.
• Compartmentation survey: Covers the entire fire compartment boundary — walls, floors, fire stopping, cavity barriers, and doors. A broader assessment of the building’s passive fire protection.

Many buildings need both. Fire doors are one element of compartmentation, but the walls, floors, and fire stopping are equally important. A building can have perfect fire doors but still have compromised compartmentation if the fire stopping around service penetrations is missing.

How Often Should Compartmentation Be Surveyed?

There is no single prescribed frequency, but good practice is:

• Baseline survey: Every building should have at least one comprehensive compartmentation survey
• After any building works: Re-survey areas where refurbishment, renovation, or new service installations have taken place
• Regular review: Review compartmentation as part of your annual fire risk assessment
• Higher-risk buildings: More frequent surveys may be required under the Building Safety Act 2022

What Happens After the Survey?

If defects are found, remedial works are needed. This typically involves:

• Fire stopping installation — using certified intumescent sealants, wraps, collars, and pillows to seal penetrations through compartment barriers
• Cavity barrier installation — fitting fire-rated barriers in ceiling voids and risers
• Wall and floor repairs — reinstating fire-resistant construction where breaches have occurred
• Fire door remediation — repairing or replacing defective fire doors

All remedial works should use third-party certified products and be carried out by competent contractors. The work should be documented and signed off, ideally with a re-survey to confirm compliance.