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Guide

What is passive fire protection?

Passive fire protection (PFP) is the part of a building that stops fire and smoke spreading without any power or action: fire-resisting walls and floors, fire doors, fire stopping, cavity barriers, fire dampers and protected structure. Alarms and sprinklers are active systems. PFP is what you cannot see working until a fire happens, which is why it fails silently.

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By DC Fire & Security, Luton. Updated October 2026.

Surveys, inspections and repairs

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Passive fire protection at a glance

Passive: works by being there: walls, floors, doors, seals, barriers and coatings
Active: detects or fights fire: alarms, sprinklers, smoke control, extinguishers
Why it matters: it holds a fire in its compartment so people can leave and firefighters can work
Who is responsible: the responsible person for the building under the Regulatory Reform (Fire Safety) Order 2005

The passive measures, mapped

Measure	What it does	How it usually fails
Compartment walls and floors	Divide the building into fire-resisting cells	Holes drilled through them, damaged boards, missing fire-resisting lining
Fire doors	Hold the fire and smoke at openings in compartment lines	Wrong gaps, missing seals, broken closers, doors held open
Fire stopping	Seals gaps and penetrations through walls and floors	Untested foam or mastic, no seal at all, undocumented repairs
Cavity barriers	Stop fire travelling through hidden voids	Missing or badly fitted in roofs, ceilings and walls
Fire dampers	Close ducts where they pass through compartments	Seized, blocked or never tested
Structural protection	Keeps steel and timber strong for longer	Coatings damaged by later works

Cables passing through a compartment wall, sealed with fire stopping and labelled — Cable penetrations sealed and labelled

Pipe penetration through a metal-clad duct sealed with fire stopping and a warning label — Pipe penetration sealed, label fixed alongside

Coated board closing a service opening above a ceiling in a residential building — Opening closed with tested board and coating

Measuring the gap at the edge of a fire door with a gauge — Gap measured in millimetres, not by eye

Active versus passive

Active systems detect, signal or suppress a fire. Passive systems limit where it can go. A building needs both: an alarm gives warning, but if the fire can spread through a gap in a wall the alarm has bought little time. Our fire alarm work covers detection in commercial buildings; this page is about the part that stops the spread.

Why passive fire protection fails silently

It is hidden behind ceilings, boxing and cupboards, so nobody looks at it
Every cable, pipe or duct installed after the building was finished is a chance to leave a hole
Fire doors are knocked, repainted, wedged open and adjusted until they no longer work
Records are lost when buildings change hands, so nobody knows what was installed

How to check yours

Start with a fire risk assessment, which looks at how the whole building relies on its fire resistance.
Have the fire doors inspected door by door. See fire door inspections.
For hidden defects behind walls and in risers, commission a compartmentation survey.
Repair what is found: fire stopping for the gaps and fire door repairs or new doors for the openings.
Keep the records. Photos, schedules and certificates are the building's evidence.

Who is responsible?

The responsible person: the employer, landlord, managing agent or whoever controls the building. In a block of flats that is usually the freeholder or the managing agent acting for them. For higher-risk buildings the Building Safety Act 2022 adds duties around information and the golden thread. See the Building Safety Act explained.

Getting help

We survey, inspect and repair passive fire protection. Surveys and inspections are carried out by DC. Where work needs a third-party certificate, it is done by our BM TRADA Q-Mark / FIRAS-certificated contractors. Tell us about your building and we will say what to start with.

Related guides and services

Fire protection services — everything we offer, in one place
Fire stopping — sealing penetrations with tested systems
Compartmentation surveys — finding hidden defects
Fire door inspections — door-by-door reports
Fire door installation — certified doorsets
Fire risk assessments — the starting point for most buildings
Compartmentation survey findings — what surveys typically uncover

Certification

Who does the work

The surveys, inspections and assessments are carried out by DC. Where a third-party certificate is needed for the work itself, it is done by our BM TRADA Q-Mark / FIRAS-certificated contractors, and the certificate goes in your fire safety file. That is the evidence managing agents, councils, insurers and building control usually ask for.

Frequently asked questions

What is passive fire protection?

The parts of a building that resist fire and smoke without needing power or action: fire-resisting walls and floors, fire doors, fire stopping, cavity barriers, fire dampers and protection to the structure.

What is the difference between active and passive fire protection?

Active systems detect, signal or suppress a fire: alarms, sprinklers, smoke control and extinguishers. Passive systems stop it spreading. Buildings need both.

Is a fire door passive fire protection?

Yes. A fire door is a passive measure that keeps a compartment line intact at an opening, but only when the door, frame, seals, hinges and closer all work together.

What is compartmentation?

Dividing a building into fire-resisting compartments so a fire is contained long enough for people to escape. It depends on walls, floors, doors and fire stopping being intact.

How do I know if my passive fire protection has failed?

You usually cannot tell by looking. Fire door inspections, fire risk assessments and compartmentation surveys are how defects are found, because most breaches are hidden.

Who is responsible for passive fire protection?

The responsible person for the building under the Regulatory Reform (Fire Safety) Order 2005, which is usually the owner, landlord, employer or managing agent. Higher-risk buildings have extra duties under the Building Safety Act 2022.

Do I need a survey?

If your fire risk assessment flags concerns, the building has had works through compartment walls, or you do not know what is behind the walls, a compartmentation survey is the next step.

Can you help with my building?

Yes. We cover Luton, Bedfordshire, Hertfordshire, Buckinghamshire and London, and work in the Thames Valley and East Midlands. Send the postcode.

Tell us about your building

Not sure where to start? Email the address and what you know to info@dcsecurity.co.uk, or use the form. Luton, Bedfordshire, Hertfordshire, Buckinghamshire, London, the Thames Valley and the East Midlands.

01582 227 123Call us directly info@dcsecurity.co.ukEmail us anytime

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