In modern buildings, compartmentation is achieved by a network of coordinated fire-resistant walls, floors, and doors, effectively creating a series of sealed boxes. Each box or 'compartment' will contain a fire for the prescribed timespan in an effort to protect life, property and the lifes of firefighters.

The Fundamental Challenge in Heritage Buildings

Traditional heritage buildings (e.g., manor houses, churches, historic theatres) were constructed long before modern fire safety codes. Their very design often works against compartmentation:

• Large, Undivided Spaces: Great halls, ballrooms, worship spaces, and atriums are inherent to these buildings.
• Combustible Structure: Extensive use of timber in floors, roofs, and panelling.
• Voids and Hidden Spaces: Complex roof voids, floor voids, and service ducts allow fire and smoke to travel unseen over long distances. A small fire in a wall can quickly spread into a roof space.
• Historic Openings: Large, open staircases often act as chimneys, drawing smoke and fire vertically through the building. Gaps around original floorboards and doors are common.
• Inherent Weaknesses: Original lath and plaster ceilings and walls have limited fire resistance. Historic doors are often thin and panelled.

The Regulatory Framework in the UK

The primary legislation is the Regulatory Reform (Fire Safety) Order 2005 (England and Wales), with similar legislation in Scotland (Fire (Scotland) Act 2005) and Northern Ireland.

• The 'Responsible Person' (e.g., building owner, manager) must conduct a Fire Risk Assessment (FRA).
• The FRA must be suitable and sufficient, and for a heritage building, this requires a specialist approach. Standard prescriptive codes (like Approved Document B) are often impractical or damaging. Therefore, a fire engineering approach is essential.

This involves:

• Performance-Based Design: Instead of saying "this wall must have a 60-minute rating," the goal is: "We need to ensure occupants can escape safely, and the fire service can operate effectively." Solutions are then tailored to achieve this performance goal.
• Qualitative/Quantitative Analysis: Using tools like computational fluid dynamics (CFD) modelling to understand how fire and smoke might spread in the unique geometry of the building.

Key Strategies for Heritage Compartmentation

The goal is to achieve the necessary level of safety with the least possible intervention to the historic fabric. The hierarchy of consideration is:

1. Avoidance and Management (First Choice)
• Reducing Fire Load: Removing or carefully managing potential fuel sources like stored archives, displays, and furniture.
• Strict Control of Ignition Sources: Managing electrical systems, catering equipment, and works (e.g., hot works permits).
• Staff Training and Procedures: Ensuring vigilant monitoring and swift alarm response.


2. Passive Fire Protection (Physical Alterations)

This is where compartmentation is physically created or enhanced, but must be done sensitively.

• Upgrading Historic Doors: Instead of replacing a beautiful panelled door with a modern fire door, it can often be upgraded by:
• Adding an intumescent strip and smoke seal to the frame.
• Lining the back of the door with a thin, fire-resistant board (like Vermiculux) that is discreet.
• Ensuring a good fit to minimise gaps.
• Protecting Escape Routes: Creating protected corridors and stairways using fire-resistant materials that are visually sympathetic. This might involve lining walls with plasterboard that is then finished to match the historic aesthetic.
• Sealing Voids: Using intumescent pillows, seals, and fire-stopping mortars to block hidden routes for fire spread in floor, wall, and roof voids. This is highly effective and often invisible.
• Compartment Floors: Introducing new fire-resistant floors or upgrading existing ones (e.g., adding a fire-resistant layer from below) to separate risk areas, like between a basement kitchen and historic rooms above.


3. Active Fire Protection Systems (Supporting Compartmentation)



These systems are often crucial to compensate for the limitations of passive measures.

• Automatic Fire Detection (AFD): Early warning is critical. Wireless systems are often preferred to avoid damaging historic fabric with cables. Aspirating smoke detection (VESDA) is excellent for sensitive areas and large voids.
• Automatic Fire Suppression (Sprinklers): Arguably the single most effective measure for heritage buildings. Modern mist and water-mist systems use less water, causing less collateral damage. Sprinklers can control or extinguish a fire before it breaches compartment boundaries, effectively "managing" the inherent lack of compartmentation.
• Smoke Ventilation: Systems to control smoke movement, keeping escape routes clear.

The Role of Consultation and Specialist Advice

This process cannot be undertaken without consulting key stakeholders:

• Conservation Officer: From the local planning authority, they must approve any alterations to a listed building. Their primary concern is preserving significance.
• Historic England / Cadw / Historic Environment Scotland: Provide guidance and may be involved in major projects.
• Specialist Fire Engineer: Essential for developing a fire strategy that balances safety and conservation.
• Architect/Surveyor Specialising in Heritage: To design sensitive and appropriate physical interventions.

Fire compartmentation in heritage buildings is not about creating a perfect, modern fire-resistant box. It is about developing a holistic, engineered strategy that understands the building's unique fire dynamics.

The most successful strategies use a combination of:

• Good management to prevent fires.
• Early detection to warn of a fire.
• Automatic suppression to control the fire.
• Sensitive, targeted passive protection to compartment the highest risks and protect escape routes.

This approach ensures that these invaluable buildings are preserved for future generations without compromising the safety of those who use and enjoy them today.