Choosing Fire Passive Protection Materials – From Intumescent Coatings to Fire Doors

Fire safety in buildings is often associated with alarms, sprinklers, and evacuation procedures. While these active fire protection measures are vital, they rely on activation and human response. Passive Fire Protection (PFP), by contrast, is always working in the background. Built into the fabric of a building, it is designed to contain fire and smoke, protect structural integrity, and preserve escape routes, without any manual intervention.

At Meritas Passive Fire Protection, our mission is simple but uncompromising: to ensure owners, staff, and residents feel completely confident and secure in the fire safety of their buildings. Through carefully designed and expertly installed passive fire protection systems, we go beyond compliance to deliver continuous, unobtrusive protection that can be trusted when it matters most.

This article explores the most commonly specified passive fire protection materials, how they work, where they are used, and what UK regulations require, helping both technical and non-technical readers make informed decisions.

Understanding Passive Fire Protection

Passive fire protection is fundamentally about compartmentation. By dividing a building into fire-resisting sections, PFP limits the spread of fire and smoke, allowing occupants time to escape and emergency services time to respond.

In the UK, passive fire protection is governed primarily by The Building Regulations 2010, with detailed guidance provided in Approved Document B (Fire Safety). For occupied buildings, the Regulatory Reform (Fire Safety) Order 2005 places a legal duty on the Responsible Person to ensure that fire-resisting measures are suitable, maintained, and effective.

What is often misunderstood is that compliance is not achieved simply by installing products. Fire protection systems must be correctly specified, installed, inspected, and maintained, and this is where specialist expertise becomes critical.

Intumescent Coatings: Protecting Structural Steel

Steel is a strong and efficient construction material, but it performs poorly in fire. At temperatures above 550°C, steel can lose around half of its structural strength, potentially leading to premature collapse.

Intumescent coatings are one of the most widely used solutions to address this risk. Applied as a thin film paint, the coating reacts to heat by expanding many times its original thickness, forming a char layer that insulates the steel beneath. This delays temperature rise and allows the structure to maintain load-bearing capacity for a specified period, typically 30, 60, 90, or 120 minutes.

From a regulatory standpoint, the required fire resistance period is determined by building height, use, and occupancy, as set out in Approved Document B. However, performance also depends on accurate section factor calculations, correct dry film thickness, and strict adherence to manufacturer test data.

At Meritas, we treat intumescent protection as an engineered solution rather than a decorative finish. Our approach ensures that coatings are correctly specified for the steel profile, exposure conditions, and fire strategy of the building, providing genuine, test-backed protection rather than superficial compliance.

Fire Stopping: Sealing the Weakest Points

Even the most robust fire-resisting walls and floors can be compromised by service penetrations. Pipes, cables, ducts, and trays create gaps that allow fire and smoke to spread rapidly if left unprotected.

Fire-stopping systems are designed to reinstate the fire resistance of a compartment where it has been breached. These systems include fire-resistant sealants, mortars, collars, wraps, pillows, and coated batts. Many products are intumescent, expanding under heat to close voids created by melting services such as plastic pipes.

UK guidance is clear that fire stopping must achieve the same fire resistance as the element it penetrates. Crucially, products must be installed exactly in accordance with their test certification; substitutions or “like-for-like” assumptions can invalidate performance entirely.

Meritas places particular emphasis on the quality of fire-stopping installation and documentation. We understand that poorly installed fire stopping is one of the most common causes of fire compartment failure, which is why our work focuses on precision, traceability, and long-term integrity.

Fire Doors: Protecting Escape Routes

Fire doors are among the most visible elements of passive fire protection, yet also among the most frequently misunderstood. A fire door is not just a door leaf, it is a complete, tested assembly comprising the leaf, frame, seals, ironmongery, glazing (if present), and correct installation.

Fire doors are typically rated FD30 or FD60, providing 30 or 60 minutes of fire resistance. Their primary function is to protect escape routes such as corridors and stairwells, preventing smoke ingress and maintaining tenable conditions during evacuation.

Under the Fire Safety Order, fire doors must be maintained in efficient working order. This includes ensuring that self-closing devices function correctly, intumescent and smoke seals are intact, and gaps remain within permissible tolerances.

Meritas supports clients not only with fire door installation but with ongoing inspection and compliance strategies. We recognise that fire doors are only effective if they are properly maintained throughout the building’s life cycle.

Matching Materials to Building Risk

Choosing the right passive fire protection materials is not a matter of preference; it is a matter of risk-based design. Factors such as building use, occupancy profile, height, means of escape, and structural form all influence the required fire strategy.

For example, a residential building may place greater emphasis on compartmentation between dwellings, while a commercial building may require enhanced protection for structural steel to prevent progressive collapse. Heritage buildings may need discreet solutions that balance fire safety with conservation requirements.

This is where Meritas sets itself apart. We do not simply install products; we design and deliver integrated passive fire protection solutions aligned with the building’s fire strategy, regulatory requirements, and real-world use.

Beyond Compliance: The Meritas Approach

Fire safety legislation in the UK establishes minimum standards, but minimum standards do not always equate to maximum confidence. At Meritas Passive Fire Protection, we believe that true safety comes from depth of knowledge, attention to detail, and accountability.

Our expertise spans intumescent coatings, fire stopping, fire doors, and wider compartmentation strategies. By combining technical understanding with practical delivery, we ensure that passive fire protection systems perform as intended, not just on paper, but in reality.

For building owners, facilities managers, and duty holders, this means peace of mind. For occupants, it means a safer environment at work, at home, and in shared spaces.

If you would like expert guidance on selecting, installing, or maintaining passive fire protection systems, Meritas is here to help, setting the standard, not just meeting it.