PFC Corofil Cavity Fire Barriers

Cavity Fire Barriers

Cavity fire barriers are passive fire protection products installed within concealed wall, floor and roof cavities to restrict the unseen spread of fire and smoke.

PFC Corofil’s range includes open state cavity barriers for ventilated façades and full-fill cavity barriers for closed cavities, with solutions suitable for both horizontal and vertical installation across external wall systems, including rainscreen cladding, masonry and brickwork façades.

All cavity barrier systems are third-party tested and certified, in accordance with BS EN 1363-1 and ASFP TGD19 for open state barriers, and BS EN 1366-4 for full-fill barriers.

PFC Corofil Cavity Barrier Range

PFC Corofil offers a focused, compliant cavity barrier range comprising:

Open state COSB systems for ventilated façades
CCFS and CCFB full-fill barriers for closed cavities
Solutions for both horizontal and vertical compartmentation

Each system is designed to maintain fire safety, regulatory compliance and buildability, supporting modern construction requirements across residential and commercial projects.

What Is a Cavity Barrier?

A cavity barrier is a fire-resisting component installed within concealed voids such as:

External wall cavities behind cladding systems
Voids within timber frame construction
Ceiling and floor voids

Without cavity barriers, these spaces can allow fire and smoke to spread rapidly through a building, often undetected.

Approved Document B requires cavity barriers to be installed at key points, including:

Compartment lines
Around openings such as windows and doors
At junctions with floors and walls
At the edges of cavities

Types of Cavity Barrier

Cavity barriers are typically classified by:

Ventilation requirement (open state vs full fill)
Installation direction (horizontal vs vertical)

Open State (Ventilated) Cavity Barriers

Open state cavity barriers are used within ventilated façade systems, maintaining airflow during normal conditions while providing fire stopping when exposed to heat.

When activated by fire, the intumescent component expands to close the air gap, preventing fire and smoke spread through the cavity.

PFC Corofil Open State Range:

Open State Barrier COSB 25 – designed for cavities with a 25mm air gap
Open State Barrier COSB 44 – designed for cavities with a 44mm air gap
Open State Insert (COSI) – used in conjunction with COSB systems

These systems are designed specifically for ventilated rainscreen and façade applications, supporting airflow, drainage and moisture control while maintaining fire performance.

Horizontal Cavity Barriers

Horizontal cavity barriers are installed at floor levels within external wall cavities, preventing vertical fire spread between storeys.

PFC Corofil open state systems such as COSB barriers are suitable for horizontal applications within ventilated façades, while full-fill barriers such as CCFS are used where cavities are closed.

Vertical Cavity Barriers

Vertical cavity barriers are installed at party wall lines and compartment walls, preventing horizontal fire spread within cavities.

PFC Corofil full-fill systems such as CCFS are suitable for vertical installation across a wide range of substrates, including masonry, steel frame systems and timber constructions.

Non-Ventilated (Full-Fill) Cavity Barriers

Full-fill cavity barriers are designed for closed cavity applications, where ventilation is not required. These systems fully seal the cavity to maintain compartmentation.

PFC Corofil Full-Fill Range:

CCFS (Cavity Fire Stop)

Stone wool cavity barrier
Suitable for horizontal and vertical installation
For cavity widths up to 600mm
Provides up to 120 minutes fire resistance (integrity and insulation)

CCFB (Cavity Fire Barrier)

Stone wool barrier for masonry cavities
Designed for cavities up to 300mm
Allows compression during installation in brickwork
Provides fire resistance in line with EN 1366-4 testing

Full-fill systems can also be supplied:

Cut to specification
With foil facing
With integral DPC where required

Fire Performance and Compliance

PFC Corofil cavity barriers are:

Tested to relevant EN fire resistance standards
Third-party certified (including UL-EU certification on CCFS)
Designed for real-world applications across multiple substrates and wall types

The range provides:

Up to 120 minutes fire resistance
Protection for cavities up to 600mm wide

All products are supported with:

Technical datasheets
Certification documentation
Specification guidance via NBS Source and the PFC Corofil website

Why should you use PFC Corofil Cavity Barriers?

Enhanced fire safety – By preventing the spread of flames and heat within cavity walls, our barriers play a critical role in safeguarding lives and property.
Regulatory compliance – Our cavity fire barriers ensure compliance with stringent fire safety regulations and building codes, providing peace of mind for architects, builders, and occupants.
High performance – With fire resistance durations of up to 120 minutes, our barriers offer reliable protection, maintaining structural integrity under fire conditions.
Versatility – Suitable for a wide range of applications, including ventilated and non-ventilated cavities, as well as various types of brickwork and masonry.

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