The Art of Compartmentation:
Essential Strategies for Fire Safety in Buildings
Fire safety in buildings is often judged by what people can see: fire alarms, emergency lighting, extinguishers, and evacuation signage. Yet some of the most critical life-safety measures are entirely hidden from view. Fire compartmentation, a fundamental element of Passive Fire Protection (PFP), works continuously in the background to contain fire and smoke, protect escape routes, and limit damage from the earliest moments of a fire.
At Meritas Passive Fire Protection, compartmentation is understood as more than a regulatory requirement. It is a carefully engineered system that provides confidence and reassurance to building owners, occupants, and duty holders alike. When done properly, it delivers constant, unobtrusive protection that performs exactly as intended when it is needed most.
Understanding Fire Compartmentation
Fire compartmentation is the practice of dividing a building into fire-resisting sections, known as compartments. These compartments are formed using fire-resistant walls, floors, ceilings, and protected openings. Each compartment is designed to resist the passage of fire and smoke for a defined period, typically ranging from 30 to 120 minutes, depending on the building’s purpose, size, and risk profile.
The principle behind compartmentation is simple but powerful. By containing fire within a limited area, it slows the rate of fire spread, preserves structural stability for longer, and maintains tenable conditions in adjacent areas. This containment provides vital time for occupants to escape safely and for emergency services to intervene, while also reducing the extent of damage to the building.
The UK Regulatory Context
In the UK, fire compartmentation is primarily governed by the Building Regulations 2010, with detailed guidance set out in Approved Document B (Fire Safety). Approved Document B defines requirements for compartment sizes, fire-resisting construction, and the protection of openings that pass through compartment lines. These requirements vary depending on building type, height, and use, reflecting the differing levels of risk.
Additional guidance is provided by standards such as BS 9999, which takes a more holistic approach to fire safety design, and fire resistance test standards including BS 476 and the BS EN 1366 series. Together, these documents establish minimum expectations for performance. However, compliance alone does not guarantee real-world effectiveness.
Meritas applies these regulations with technical judgement, ensuring that fire strategies are not only compliant on paper but are fully realised in the built environment. This approach is especially important where buildings are complex, heavily serviced, or subject to change over time.
Fire-Resisting Construction and Continuity
The effectiveness of compartmentation depends on the integrity and insulation of fire-resisting walls and floors. These elements must perform as tested, maintaining their fire resistance for the specified duration without allowing flames, hot gases, or excessive heat transfer to pass through.
In practice, the greatest risks often arise at interfaces and junctions. Poor detailing, incorrect fixings, or unapproved substitutions can significantly reduce performance. Meritas focuses on maintaining continuity of fire resistance throughout the building, ensuring that what has been designed is what is actually delivered on site.
Service Penetrations and Fire Stopping
Modern buildings are densely packed with services, including electrical cabling, data infrastructure, pipework, and ventilation systems. Every service that passes through a fire-resisting element creates a potential weakness if it is not properly sealed.
Fire stopping is the process of reinstating fire resistance where it has been breached by services. This is a highly technical discipline that relies on tested systems, correct installation, and close attention to detail. Products must be matched precisely to the service type and supporting construction and installed exactly as tested.
Meritas brings specialist expertise to complex service penetrations, ensuring that compartment lines remain intact and that fire-stopping solutions perform as intended under fire conditions.
Fire Doors as Part of the Compartment Strategy
Fire doors play a crucial role in compartmentation, allowing buildings to function normally while still providing fire resistance when required. However, they are also one of the most common points of failure. Even a door with the correct fire rating will not perform if gaps are excessive, seals are missing, or hardware is incorrect.
A fire door must be considered as a complete door set, including the leaf, frame, seals, glazing, ironmongery, and installation. Meritas adopts a system-based approach, ensuring that fire doors form an effective and reliable part of the overall compartmentation strategy.
Hidden Risks: Cavities and Voids
Fire does not always spread where it can be easily seen. Concealed spaces such as ceiling voids, raised floors, and wall cavities can allow fire and smoke to bypass compartment lines entirely. Without correctly installed cavity barriers and fire-stopping measures, a fire can spread undetected until it is well established.
Meritas places strong emphasis on these concealed areas, recognising that effective compartmentation must address both visible and hidden routes of fire spread.
Compartmentation, Accountability, and the Golden Thread
The introduction of the Building Safety Act 2022 has placed greater responsibility on duty holders to demonstrate that fire safety systems are properly designed, installed, and maintained. Central to this is the concept of the “Golden Thread” of information, providing clear, accurate, and accessible records throughout a building’s lifecycle.
Meritas supports this requirement by delivering robust documentation, clear evidence of compliance, and transparent reporting. This not only supports regulatory obligations but also gives building owners and managers confidence in the long-term performance of their fire safety measures.
Beyond Compliance: The Meritas Approach
While regulations define what must be achieved, expertise determines how well it is achieved. Fire compartmentation failures are rarely caused by a lack of rules; they are usually the result of misinterpretation, poor coordination, or inadequate workmanship.
Meritas goes beyond compliance by combining technical knowledge with practical experience. This ensures that fire strategies are understood, tested systems are correctly applied, and risks are identified early. The result is compartmentation that performs reliably in real-world conditions, not just during inspections.
Confidence Built on Continuous Protection
Passive fire protection does not rely on activation, power, or human intervention. When properly designed and installed, it works continuously for the life of the building. This silent reliability is what makes compartmentation such a critical element of fire safety.
Through expertise in Passive Fire Protection and a commitment to setting higher standards, Meritas ensures that owners, staff, and residents can feel genuinely secure in the safety of their buildings. Compartmentation, when treated as an art as well as a science, becomes one of the most effective tools in protecting lives, property, and peace of mind.