A compartment line can appear complete until a cable bundle, altered ceiling, unsealed riser or poorly fitted access panel breaks it. That is why knowing how to inspect fire compartmentation is not a box-ticking exercise. It is a disciplined assessment of whether the building fabric will resist fire and smoke for the period intended, protecting escape routes, limiting damage and giving the fire service valuable time.
For principal contractors, building owners and facilities teams, the objective is twofold: identify deficiencies before they become life-safety risks, and create evidence that remedial decisions have been made on a sound, traceable basis. The inspection must consider more than visible mastic around services. It must follow each compartment boundary, understand its construction and examine every interface that could compromise its performance.
Start with the intended compartment strategy
An inspection should begin before anyone enters a riser or lifts a ceiling tile. Obtain the fire strategy, relevant drawings, specifications, test evidence where available, previous inspection reports and records of alterations. These documents establish what the building is meant to achieve: the location of compartment walls and floors, required fire-resistance periods, protected shafts, cavity barriers, fire curtains and the treatment of structural elements.
On refurbishment projects, this information may be incomplete or no longer reflect the building as it stands. That does not remove the need to inspect. It changes the approach. The surveyor should record assumptions, identify unknown constructions and recommend opening-up works where the fire-resisting line cannot be verified visually.
The required standard also depends on the building’s use, height, occupancy and fire strategy. A hospital ward, occupied residential block, hotel and office floor may all present different risk profiles and operational constraints. In England, the inspection should be considered alongside the relevant fire-safety duties and Building Regulations requirements, including Approved Document B where applicable. Projects elsewhere in the UK must be assessed against the relevant national requirements.
How to inspect fire compartmentation systematically
A reliable inspection follows the compartment line rather than inspecting isolated defects. Start at a known point and trace the boundary through walls, floors, ceiling voids, service risers, façades, roof spaces and plant areas. A wall that appears intact at room level may stop at a suspended ceiling, leaving an unprotected void above.
The survey should establish three things: what the barrier is made from, whether it is continuous, and whether every penetration and junction has been protected with a suitable system. Record the exact location, orientation and condition of each item. Photographs should include a wider image for location and a close image of the defect, with a reference to the drawing grid, floor level or asset identification number.
Inspect walls, floors and junctions
First, confirm that compartment walls and floors are continuous and free from visible damage. Look for cracks, gaps at slab edges, unsealed perimeter joints, incomplete wall heads and holes left by previous trades. Pay particular attention to junctions between different substrates, such as blockwork meeting concrete, drywall meeting steelwork, or masonry interfaces in heritage buildings.
Movement is a frequent issue. A seal that is adequate in a static opening may not be appropriate where deflection, vibration or thermal movement is expected. The inspection should therefore consider the joint type and likely movement, not simply whether a sealant is present.
Where the construction is concealed, targeted opening-up may be necessary. This should be planned carefully, particularly in occupied buildings and sensitive historic fabric. The purpose is not to cause unnecessary disruption, but to obtain sufficient evidence that the compartment line continues as designed.
Check service penetrations and firestopping systems
Service penetrations are among the most common failure points. Inspect cables, cable trays, conduits, plastic and metallic pipes, ductwork, mixed-service openings and redundant penetrations. A firestopping system must suit the service, aperture, substrate and required fire rating. A product used in isolation is not evidence of compliance; it is the tested or assessed system, installed in the specified configuration, that matters.
Look for missing or damaged firestop products, unsupported services, excessive annular gaps, incorrect backing materials, incomplete wraps around combustible pipes and penetrations added after the original work. Cable additions are particularly easy to overlook. A once-compliant seal can be compromised when new cables are pushed through it without reinstatement.
Ductwork requires close scrutiny. Where a duct passes through a fire-resisting element, the arrangement may require a correctly specified fire damper, suitable firestopping around the sleeve and access for future testing and maintenance. Damper access panels that are inaccessible, incorrectly located or not reinstated after maintenance can undermine the intended protection.
Examine ceiling voids, cavities and façade interfaces
The most significant defects are often hidden above ceilings, within raised floors or behind wall linings. Inspectors should not assume that a ceiling provides the compartmentation line. Confirm whether the wall is required to continue to the soffit, and inspect the void where access allows.
Cavity barriers need the same level of attention. They must be correctly positioned, continuous and compatible with the cavity construction. In external wall systems, roofing details and internal cavity walls, missing, displaced or compressed barriers can allow fire and smoke to travel beyond the intended compartment.
At façades and slab edges, inspect perimeter fire barriers for continuity, correct compression and protection against damage. These locations are technically demanding because they may need to accommodate façade movement while maintaining fire resistance. They should be assessed against the relevant system details rather than a generic visual standard.
Assess quality, not appearance alone
A neat finish is useful, but it is not a fire test. The inspector should compare the installation with the manufacturer’s installation guidance, tested detail or suitable fire-engineering assessment. Dimensions, depth, fixing centres, substrate condition and the arrangement of services can all affect performance.
This is where competency matters. Some defects are obvious: an open hole through a riser wall needs no interpretation. Others are less clear, particularly where multiple services pass through one aperture, where the original construction has been altered, or where modern materials meet historic fabric. A competent passive fire protection specialist can distinguish between a cosmetic imperfection and a condition that calls the entire system’s performance into question.
Sampling also requires judgement. Inspecting a proportion of repetitive installations can be appropriate where workmanship, products and conditions are genuinely consistent. It is less reliable in complex refurbishment work, buildings with numerous later alterations, or areas where hidden conditions are likely. A sample should never be presented as proof that every uninspected item is compliant.
Create an evidence trail that supports action
The final report should give the client more than a defect list. It should identify each issue, its location, the affected compartment line, likely consequence, recommended action and priority. Clear language is essential. “Seal gap” is not enough; the record should state whether the gap is at a compartment wall head, around a cable tray, within a riser or at a floor perimeter.
A practical report normally includes annotated drawings, photographs, defect references, a schedule of remedial works and limitations of the survey. Where opening-up was not possible, say so. Where a construction cannot be confirmed, identify the further investigation required. Transparent limitations protect the client from false assurance and help the project team plan the next stage properly.
After remedial works, reinspect the completed installation. Capture before-and-after photographs, product identification, installer details and any relevant certification. This evidence is particularly valuable for future maintenance, tenant alterations, fire-risk assessments and handover records. In higher-risk and complex buildings, disciplined information management is part of maintaining control throughout the building’s life.
Prioritise defects by life-safety risk
Not every observation has the same urgency. Open penetrations in protected escape routes, risers or compartment floors may require immediate action, especially where they create a direct route for smoke and fire. Defects affecting healthcare, sleeping accommodation or occupied residential premises may also demand a faster response because evacuation is more challenging.
Lower-priority items may still need planned repair, but they should not distract from breaches that compromise the core compartment strategy. The priority should reflect the location, fire-resistance requirement, size and nature of the opening, services involved, occupancy and existing mitigation measures.
Where remedial works are required, appoint a third-party-approved passive fire protection specialist with experience of the relevant substrates and systems. ATOL Construction approaches this work as the final barrier between a building and fire: a responsibility that requires verified systems, careful installation and accountable records.
A thorough inspection does more than find gaps. It gives the dutyholder a clear view of where fire and smoke could travel, what must be corrected and how the integrity of the building can be protected long after the work is complete.
