Fire compartmentation is a critical element in building fire safety. It involves dividing a structure into separate fire-resistant areas to slow the spread of fire and smoke. This delay provides more time for occupants to evacuate safely and for emergency services to respond. However, in many UK buildings, compartmentation fails due to poor design, construction faults or improper maintenance. These failures increase the risk of uncontrolled fire spread, putting lives and property at serious risk.

What is Fire Compartmentation?

Fire compartmentation refers to the use of fire-resistant walls, floors and ceilings to separate sections of a building. These barriers are designed to contain fire and smoke within a defined space for a specific period, typically 30 to 120 minutes. This containment helps protect escape routes and reduces the likelihood of fire moving quickly through a structure.

Role in Passive Fire Protection

Fire compartmentation is part of a building’s passive fire protection system. Unlike active measures such as alarms and sprinklers, passive systems are built into the structure. They require no activation and provide continuous protection by resisting fire and smoke movement through physical barriers.

Regulatory Context in the UK

UK building regulations set out clear requirements for fire safety in new and existing buildings. Approved Document B outlines how compartmentation should be designed and maintained. Failure to comply may result in enforcement action and increased liability in the event of an incident.

The Fire Safety Act 2021 and the Regulatory Reform (Fire Safety) Order 2005 further strengthen these obligations, particularly for high-risk residential buildings. Those responsible for fire safety and fire stopping should take a fire stopper course to get an understanding of these duties and how to fulfil them.

7 Common Places Fire Compartmentation Fails

1. Risers and Service Voids

Service risers are vertical shafts used to run cables, pipes and ducts through multiple floors. These often breach fire compartments if left unsealed or poorly patched. Over time, maintenance work or upgrades can worsen the issue as trades may remove fire-stopping to access services but fail to reinstate it.

2. Ceiling Voids and Suspended Ceilings

Ceiling voids often contain hidden gaps where fire or smoke can bypass fire barriers. Installations such as lighting or air conditioning systems may require cutting through these areas. If contractors do not seal the penetrations correctly, the compartment line is compromised.

3. Door Upgrades or Poorly Maintained Fire Doors

Fire doors are essential to any compartmentation strategy. Problems occur when they are damaged, wedged open or replaced with non-rated alternatives. Even small faults like worn seals or incorrect gaps around the frame can allow smoke or flames to pass through. Regular checks and maintenance are needed to ensure fire doors remain effective.

4. Incomplete or Damaged Fire-Stopping

Fire-stopping materials seal gaps around cables, pipes and ducts where they pass through compartment walls or floors. These materials must be correctly applied to maintain integrity. Failures are common where fire-stopping is poorly installed, removed during works or damaged over time.

5. Unprotected Ductwork and Dampers

Ductwork can act as a hidden path for fire and smoke. If ducts pass through compartment lines without fire dampers or fire-resistant sleeving, they break the barrier. Even when dampers are present, they must be properly installed and maintained to function during a fire.

6. Roof Spaces and Loft Voids

Roof spaces are often overlooked during fire safety checks. These areas can run across multiple compartments, allowing fire to travel unchecked if proper fire barriers are not installed. In older buildings or conversions, compartment lines rarely extend fully into the loft or roof void. Gaps at party walls, missing firestops and exposed timber structures are all common risks. Once fire enters the roof, it can rapidly spread across the building.

7. Penetrations After Refurbishment or Retrofit Work

Refurbishment and retrofit projects often involve new electrical or mechanical installations. This work usually requires creating openings in existing walls or floors, many of which serve as compartment lines. Contractors may drill through fire barriers to run cables or plumbing but leave the holes unsealed or inadequately patched. These breaches are especially dangerous because they are usually hidden behind walls or ceiling tiles. A failure to re-establish fire integrity following such work undermines the entire compartmentation strategy.

Identifying and Preventing Failures

Early detection and proper rectification are essential to prevent compartmentation issues from becoming major hazards. Building owners and facility managers should prioritise checks and repairs as part of regular fire risk assessments.

A fire compartmentation survey involves a thorough inspection of all fire barriers in a building. This includes checking voids, service risers, doors, floors and roof spaces. These surveys are usually carried out by qualified fire engineers or passive fire protection specialists. They identify non-compliant installations, unsealed penetrations and other failure points. Reports from these surveys guide necessary remediation work.

Only trained professionals should carry out fire-stopping installations or repairs. Other workers whose work may involve coming into contact with fire safety systems should also take fire safety training, perhaps through health and safety awareness courses.

Fire compartmentation is one part of a larger framework aimed at keeping buildings safe. Its effectiveness depends on how well it integrates with other fire safety and health protocols.

No Room for Assumptions

Fire compartmentation failures are often invisible and easy to miss. They may remain undetected for years until a fire exposes the risks. When barriers are breached or neglected, fire spreads rapidly, threatening lives and property.

To avoid this, building managers must treat compartmentation as a living system that requires maintenance, inspection and prompt repair. Regular fire surveys, competent contractors and staff training are all part of the solution. While the problem areas are well known, action is often delayed or ignored. Proactive management can prevent disaster.