Fire Compartmentation Survey: A Complete Guide
If you manage, own or control a building, a Fire Compartmentation Survey can play a critical role in your fire safety strategy. It helps you understand whether the passive fire protection within a building will perform as intended during a fire. It can also reveal hidden defects that may undermine evacuation, firefighting operations and legal compliance.
For many dutyholders, compartmentation defects sit unseen above ceilings, inside risers, behind service penetrations and within concealed voids. Yet these defects can allow smoke and fire to spread rapidly, compromising escape routes and putting lives at risk.
A Fire Compartmentation Survey gives you evidence of how your building performs, where weaknesses exist, and what remedial actions you need to prioritise.
This guide explains what a Fire Compartmentation Survey involves, who needs one, what surveyors inspect, common defects found, relevant legal duties, and how surveys support wider fire risk management.
What Is a Fire Compartmentation Survey?
A Fire Compartmentation Survey is a systematic inspection of the passive fire protection measures that subdivide a building into fire resisting compartments.
Its purpose is to assess whether walls, floors, ceilings, risers, shafts, service penetrations, cavity barriers and fire stopping maintain the fire resistance needed to contain fire and smoke for the designed period.
In simple terms, compartmentation is intended to stop fire spreading from one part of a building to another.
A survey tests whether that protection remains intact.
Typical surveys assess:
- Fire resisting walls and compartment walls
- Compartment floors and ceilings
- Fire stopping around penetrations
- Service risers and shafts
- Cavity barriers
- Fire dampers
- Fire doors, where within scope
- Ceiling voids and hidden spaces
- Structural protection to steelwork where relevant
- Junctions between building elements
The survey often combines visual inspection, intrusive inspection and opening up works.
It is not unusual for surveys to reveal significant defects, even in relatively modern buildings.
Why Fire Compartmentation Matters
Passive fire protection works continuously. Unlike alarms or sprinklers, it does not rely on activation.
When it performs correctly, compartmentation can:
- Slow fire growth and spread
- Protect escape routes
- Support phased or stay put evacuation strategies
- Protect firefighters
- Limit smoke migration
- Reduce damage and business interruption
- Improve resilience of the building
When it fails, consequences can be severe.
Poor compartmentation has been identified in numerous post-fire investigations and has been a major focus of regulatory scrutiny following the Grenfell Tower fire.
Common defects often arise from later alterations, poor workmanship, undocumented services installations, maintenance works or deterioration over time.
A building may appear compliant on the surface while concealed defects seriously compromise performance.
That is why a Fire Compartmentation Survey often reveals risks not identified through a standard fire risk assessment alone.
What Is Fire Compartmentation?
Compartmentation divides a building into fire resisting cells designed to contain fire for a specified duration, often 30, 60, 90 or 120 minutes depending on the design.
Examples include:
- Flats separated from common corridors
- Protected stair cores
- Plant rooms enclosed from occupied areas
- Fire resisting risers around services
- Protected escape routes
- Separation between tenancy units
- Fire resisting floors between storeys
The concept supports life safety by giving occupants time to escape before conditions become untenable.
It also supports evacuation strategies.
For example:
A stay put strategy in residential buildings often depends heavily on robust compartmentation.
If compartment walls or floors are breached, that strategy may be undermined.
This is why compartmentation surveys are frequently commissioned alongside fire risk assessments and external wall appraisals.
What Does a Fire Compartmentation Survey Include?
A professional Fire Compartmentation Survey often follows several stages.
1. Document Review
Surveyors may review:
- Fire strategy documents
- As built drawings
- O&M manuals
- Previous survey reports
- Fire risk assessments
- Building plans
- Remedial records
- Construction details
This helps establish intended compartment lines and fire resisting elements.
2. Visual Inspection
Inspectors review accessible areas for visible defects such as:
- Damaged fire stopping
- Poorly sealed penetrations
- Unprotected cable trays
- Inadequate cavity barriers
- Damaged fire doors
- Breaches in compartment walls
- Gaps above suspended ceilings
3. Intrusive Opening Up
Many critical defects are concealed.
Opening up works may include:
- Ceiling void inspections
- Access panels
- Opening risers
- Wall probes
- Inspection behind service penetrations
- Investigation of cavity barriers
This stage often identifies the most significant defects.
4. Recording and Risk Grading
Findings are typically recorded using:
- Marked up drawings
- Photographic evidence
- Defect schedules
- Risk categorisation
- Prioritised remedial actions
Many reports distinguish critical life safety defects from lower priority issues.
5. Remedial Recommendations
Reports usually recommend:
- Fire stopping repairs
- Installation or replacement of cavity barriers
- Fire damper remediation
- Compartment wall repairs
- Penetration sealing upgrades
- Validation testing where required
- Further intrusive investigations if sampling indicates wider defects
Common Defects Found in Fire Compartmentation Surveys
Many buildings contain recurring issues.
Common defects include:
Unsealed Service Penetrations
One of the most frequent problems.
Cables, ducts and pipes pass through fire resisting walls and floors but lack suitable fire stopping.
Even small gaps can permit smoke and flame spread.
Poor Fire Stopping Installations
Products may be:
- Incorrectly installed
- Mixed in untested combinations
- Damaged
- Incomplete
- Unsupported by certification
Improvised sealing with foam or mastic often appears in defective installations.
Missing or Defective Cavity Barriers
Missing cavity barriers remain a common issue in both new and existing buildings.
These can allow hidden fire spread.
Compartment Walls Stopping at Ceiling Level
Walls sometimes terminate above suspended ceilings rather than extending to the soffit.
This can create concealed routes for fire spread.
Damaged Fire Dampers
Fire dampers may be absent, inaccessible, untested or improperly installed.
Breached Risers and Shafts
Service upgrades often leave openings unsealed.
Defective Fire Doors
Although often surveyed separately, compartmentation surveys may identify missing seals, damaged leaves or inadequate door sets affecting compartment integrity.
Which Buildings Need a Fire Compartmentation Survey?
Many premises can benefit. Common examples include:
Residential Buildings
Including:
- High rise blocks
- Medium rise residential blocks
- Social housing
- Student accommodation
- Build to rent developments
- Care homes
BS 9792 provides a framework relevant to housing fire risk assessments.
Commercial Buildings
Including:
- Offices
- Retail premises
- Warehouses
- Hotels
- Mixed use developments
- Industrial premises
For non-housing premises, structured fire risk assessment approaches are often informed by PAS 79-1.
Higher Risk Buildings
Under the Building Safety Act 2022, many dutyholders commission compartmentation surveys to support broader building safety management.
Buildings Undergoing Refurbishment
Alterations often compromise passive protection.
Surveys can validate existing conditions before or after works.
Buildings with Stay Put Strategies
Compartment integrity is fundamental where evacuation strategies rely on containment.
Is a Fire Compartmentation Survey a Legal Requirement?
Legislation does not generally prescribe a universal duty to commission a compartmentation survey by name.
But legal duties often make such surveys necessary to demonstrate compliance.
Under the Regulatory Reform (Fire Safety) Order 2005, responsible persons must take suitable fire precautions and undertake a suitable and sufficient fire risk assessment.
Compartmentation can form a critical part of that assessment.
If you cannot verify compartment integrity, you may struggle to demonstrate you have adequately assessed fire risk.
In some buildings, especially complex or higher risk premises, a Fire Compartmentation Survey may be the practical way to discharge that duty.
The Fire Safety (England) Regulations 2022 also strengthened duties for many residential buildings.
The Fire Safety (Residential Evacuation Plans) (England) Regulations 2025 add further duties relevant to some specified residential buildings from April 2026.
Regulators increasingly expect evidence.
A survey often provides that evidence.
Fire Compartmentation Survey vs Fire Risk Assessment
These are not the same.
A fire risk assessment identifies fire risks and necessary precautions.
A Fire Compartmentation Survey examines a specific part of passive protection in greater technical depth.
Think of the survey as specialist evidence that may support or inform the fire risk assessment.
Often they work together.
A fire risk assessor may recommend a compartmentation survey where:
- Building history is uncertain
- Intrusive inspection has not occurred
- Hidden defects are suspected
- Refurbishment has taken place
- Stay put strategies rely on compartment performance
- Previous surveys identified defects needing validation
How Often Should You Carry Out a Fire Compartmentation Survey?
There is no universal frequency.
It depends on risk.
Triggers often include:
- Acquisition of a building
- Major refurbishment
- Change of use
- After fire incidents
- Before major remediation programmes
- Following intrusive works affecting services
- Where previous surveys identified widespread defects
- Periodically in higher risk buildings as part of assurance regimes
Some dutyholders adopt cyclical survey programmes.
Others use risk-based sampling.
The right frequency depends on the building and risk profile.
What Does a Fire Compartmentation Survey Report Include?
A good report should provide more than photographs of defects.
It should help you make decisions.
Typical outputs include:
- Scope and methodology
- Areas inspected
- Limitations and access constraints
- Defect schedule
- Photographic evidence
- Marked drawings
- Risk prioritisation
- Recommended remedial actions
- Further investigation requirements
- Summary of implications for life safety strategy
Some reports also support tendering for remedial works.
What Happens After the Survey?
The survey is often the start, not the end.
Typical next steps include:
Prioritise Critical Defects
Life safety critical breaches often need urgent action.
Plan Remediation
Use competent contractors using tested systems and certified products.
Verify Repairs
Post-remedial validation is often essential.
Repair works that are not inspected can simply introduce new defects.
Update Your Fire Risk Assessment
Survey findings may change risk assessments and evacuation assumptions.
Maintain Records
Document:
- Findings
- Remediation
- Certifications
- Verification inspections
- Ongoing maintenance strategy
This helps demonstrate compliance.
Choosing the Right Fire Compartmentation Survey Provider
Ask practical questions. Do they:
- Understand passive fire protection systems?
- Have experience with your building type?
- Carry out intrusive inspection where required?
- Use clear defect classification?
- Provide actionable remediation advice?
- Understand links to fire strategy and fire risk assessments?
- Have experience in higher risk residential buildings?
Competence matters. A poor survey can create false reassurance.
Fire Compartmentation Surveys and Building Safety
Compartmentation has become central to building safety governance.
For many dutyholders, surveys support:
- Building safety cases
- Golden thread information
- Remediation strategies
- Resident safety assurance
- Regulatory engagement
- Due diligence during acquisition
Increasingly, investors, managing agents and regulators expect evidence rather than assumptions.
A Fire Compartmentation Survey helps provide that evidence.
Why Early Surveys Save Money
Many clients commission surveys only after problems emerge. That often increases cost.
Early surveys can:
- Identify defects before they worsen
- Avoid disruptive emergency remediation
- Support planned maintenance budgets
- Reduce liability exposure
- Inform refurbishment design
- Reduce scope creep in remediation projects
Finding issues early often costs less than reacting late.
Key Takeaways
A Fire Compartmentation Survey helps you verify whether your building’s passive fire protection will perform as intended.
It can reveal hidden defects that ordinary inspections may miss.
A survey supports legal compliance, fire risk management and occupant safety.
It is particularly important in higher risk, complex and residential buildings where evacuation strategies depend on compartment integrity.
Most importantly, it gives you evidence for decisions.
And in fire safety, evidence matters.
FAQs About Fire Compartmentation Survey
What is a Fire Compartmentation Survey?
A Fire Compartmentation Survey inspects fire resisting walls, floors, penetrations, cavities and related passive fire protection measures to assess whether they can contain fire and smoke as intended.
Who needs a Fire Compartmentation Survey?
Landlords, managing agents, responsible persons, developers, housing providers and employers may all need one, particularly for higher risk or complex buildings.
Is a Fire Compartmentation Survey the same as a fire risk assessment?
No. A fire risk assessment considers wider fire risks. A Fire Compartmentation Survey focuses specifically on passive fire protection and compartment integrity.
What defects are commonly found?
Typical issues include missing fire stopping, unsealed penetrations, breached compartment walls, missing cavity barriers and defective fire dampers.
How intrusive is a Fire Compartmentation Survey?
It depends on scope. Some are largely visual. Others involve opening up ceilings, risers or walls to inspect concealed defects.
How often should compartmentation be surveyed?
There is no fixed universal interval. Frequency should reflect risk, building type, changes, previous findings and maintenance history.
Can poor compartmentation affect stay put strategies?
Yes. Stay put strategies often depend on robust compartmentation. Defects may undermine that strategy.
Does a Fire Compartmentation Survey include remedial works?
Usually the survey identifies defects and recommends repairs. Remedial works are normally separate.
Can a Fire Compartmentation Survey help with compliance?
Yes. It can support evidence of compliance with fire safety duties and help inform a suitable and sufficient fire risk assessment.
What should I do if a survey finds major defects?
Prioritise urgent risks, commission competent remediation, verify repairs and review your wider fire safety strategy.
Need help with a Fire Compartmentation Survey
Anstey Horne’s expert team of fire safety professionals are here to assist with comprehensive and compliant Fire Compartmentation Surveys. Whether you manage a single block or a national portfolio, we can help you stay safe and compliant.
Get in touch with us today to arrange a no-obligation consultation - please call 020 4534 3130.
If you would rather we called you instead, please fill in our Contact form and we will be in touch.
For further information on all aspects of this service see the collection of articles in our blog.
To commission a Fire Compartmentation Survey please call 020 4534 3130.
For further information on Fire Risk Assessment, Retrospective Fire Strategies, FRAEWs or advice in respect of your obligations as a building owner, developer or manager, please contact :
Sarah Taylor
Business Support Manager
Building Surveying
London