Fire Compliance:
Managing the details behind effective compartmentation
Fire stopping is not simply an item to close out once services are installed. It is a fundamental part of maintaining a building's compartmentation strategy. Every service penetration, construction interface, door opening, and junction within a fire-resisting element can compromise its performance if it is not properly designed, coordinated, installed, and evidenced.
The challenge is that passive fire protection rarely sits within one party’s scope. The fire consultant establishes the strategy, the architect develops the compartmentation and construction details, the structural and MEPH designs create interfaces with those elements, and specialist subcontractors ultimately install the systems. Each package can appear compliant when reviewed individually, while the completed construction still contains gaps between them.
For us, this is where design management plays an important role: understanding the interfaces, establishing the required evidence, and ensuring the final solution is coordinated and can demonstrate compliance before it is built.
FIRE STOPPING IS AN INTERFACE, NOT A PRODUCT
A common misconception is that specifying a fire-stopping product resolves the requirement. It does not. Fire resistance is achieved through a completely tested or appropriately assessed system. Its suitability depends on the supporting construction, service type, penetration size, opening dimensions, orientation, required period of fire resistance and installation arrangement.
A tested penetration seal within one type of drylining system cannot automatically be assumed to provide the same performance when the wall construction, stud arrangement, service configuration or opening size changes.
The same principle applies across passive fire protection. Drylining interfaces, deflection heads, wall-to-soffit junctions, fire doors, service penetrations, structural interfaces and changes in substrate all need to be considered as part of the overall compartmentation strategy.
The design therefore needs to go further than identifying where fire stopping is required. It needs to establish how the fire-resisting construction is maintained at each condition.
MANAGING NON-STANDARD DETAILS
Standard tested details will not cover every condition encountered on a complex construction project. This is particularly relevant on refurbishment and fit-out projects, where new construction frequently interfaces with retained structure, existing substrates or geometries that do not correspond directly with a manufacturer's standard tested arrangement. In these circumstances, simply selecting the nearest standard detail is not sufficient.
Where a proposed arrangement falls outside the direct field of application of existing test evidence, we work closely with the project fire consultant, passive fire specialists, manufacturers and other members of the design team to establish what further evidence is required. Depending on the condition, this can include manufacturer technical assessments, fire engineering assessments or engineering judgements supported by relevant test evidence, project-specific detailing and, where necessary, physical fire testing.
Our role is to manage that process through to conclusion; identifying the non-standard condition, obtaining the relevant technical input, coordinating amendments between disciplines and ensuring the final agreed detail is captured within the construction information. This is particularly important for drylining and compartmentation details. Small changes to board build-up, supporting construction, service configuration or junction details can move an installation outside the scope of the evidence being relied upon.
The question cannot simply be: does the product have a fire rating? The question is whether suitable evidence supports the complete proposed construction for that particular application.
FROM ENGINEERING JUDGEMENT TO FIRE TESTING
In some cases, existing test evidence does not adequately represent the proposed construction. Where that occurs, resolving the detail can require considerably more technical coordination than issuing a standard manufacturer's detail.
We actively develop and manage the bespoke fire details through this process, including liaising directly with the fire consultant, specialist subcontractors, and manufacturers to establish appropriate engineering judgements and determine where additional testing is required.
Where physical testing is necessary, our involvement extends beyond arranging the test. We have attended fire and burn tests to understand first-hand how proposed systems perform under test conditions, ensuring that the construction presented for testing accurately represents the intended site installation and that any observations or failures are fed back into the design.
After testing, an equally important evidence and approval process follows. Test reports, assessments, supporting technical information and revised construction details need to be brought together into a coherent package. Any limitations or conditions in the test evidence must be reflected in the final design, and the agreed solution must be reviewed by the appropriate project stakeholders before construction proceeds.
We manage this process through to technical close-out, working with the fire consultant, design team, specialist subcontractors, and Building Control, as applicable, to establish a clear and auditable basis for the final detail.
Testing is therefore not treated as an isolated exercise. The objective is to turn the test evidence into a detail that can be designed, installed, inspected and ultimately demonstrated as compliant.
FIRE DOORS AND COMPARTMENTATION
Fire doors are another area where the interface between design, specification and installation is critical. A fire door is not simply a door leaf with a fire rating. The doorset's performance depends on the complete assembly, including the leaf, frame, ironmongery, glazing where applicable, seals, supporting construction, and the interface between the frame and surrounding wall. This becomes increasingly complex where fire doors are incorporated into bespoke architectural packages or non-standard wall constructions.
Our experience includes designing fire doors to ensure compliance with numerous test data components, coordinating fire-door requirements with architectural, joinery and drylining packages, reviewing interfaces with specialist suppliers, and ensuring the supporting construction and installation details align with the evidence being relied upon.
Where an architectural requirement moves away from a standard tested arrangement, the implications need to be understood early. A seemingly minor amendment to a frame profile, door size, ironmongery arrangement, glazed opening, or adjacent wall construction may affect the evidence supporting the doorset.
The design management process provides the control needed to identify those changes before manufacture and installation.
COORDINATION WITHIN RETAINED STRUCTURES
The risk becomes particularly acute on refurbishment projects. A new-build project can, to a large extent, develop compartmentation around known construction build-ups. A refurbishment must often achieve a current fire strategy within an existing building where the retained structure was never designed around the proposed works. Every location where new fire-resisting construction meets retained fabric therefore needs to be understood and coordinated, not assumed.
On our Mode Tower project at 125 London Wall, an 18-storey commercial refurbishment, existing retained elements created several conditions that required further consideration against the proposed fire strategy. We led a dedicated coordination exercise to identify and resolve these interfaces, bringing together the fire consultant, Building Control, design team and specialist subcontractors to establish technically acceptable solutions before the relevant works were completed on site.
This process goes beyond securing approval against a drawing. The agreed detail must be capable of being installed within the physical constraints of the existing building, inspected once constructed and supported by the appropriate technical evidence.
EARLY ENGAGEMENT WITH THE MEPH
By the time an MEPH service reaches a compartment wall on site, many of the decisions affecting the fire-stopping solution have already been made. The route has been established. The opening may already have been formed. Supports, insulation and adjacent services may already determine the available space. Trying to resolve passive fire protection at that point unnecessarily limits the available solutions.
Early engagement allows service routes, opening sizes, penetration types, separation distances and access requirements to be reviewed alongside the passive fire strategy while the design can still be adjusted. This is particularly important within heavily serviced areas, risers and ceiling voids where several systems may compete for a relatively small area of compartment wall.
Good coordination asks the question before installation “Can this arrangement actually be fire stopped using an evidenced system?” If the answer is no, the service arrangement should change while it remains on the drawing, not after the penetration has been formed.
EVIDENCE, INSPECTION AND THE GOLDEN THREAD
Designing a compliant detail is only part of the process. The completed installation also needs to demonstrate that what was designed is what was built.
For higher-risk buildings, the Building Safety regime places specific requirements around maintaining a digital golden thread of information capable of demonstrating compliance with the Building Regulations throughout the design and construction process. The same principles of controlled, accessible and auditable information are good practice across our wider project portfolio. For passive fire protection, this may include the relevant product and system information, tested or assessed details, location references, installation records, photographic evidence, inspection records and details of the competent installer.
Our approach is to establish those information requirements early rather than attempting to reconstruct the compliance record at handover. Where non-standard details, engineering assessments or test reports form part of the compliance strategy, those documents are incorporated into the project record so there is a clear link between the issue identified, the technical evidence obtained, the detail approved and the installation completed on site.
WHERE THE LIABILITY SITS
Passive fire protection is not only a technical issue. It forms part of the wider statutory obligations applying to those involved in designing and carrying out building work. The Building Safety Act introduced a strengthened dutyholder and competence regime for building work in England and has increased the emphasis on demonstrating how Building Regulations compliance has been managed through design and construction.
The implications are clear: passive fire protection needs to be technically robust and supported by an evidence trail that reflects what was actually designed and installed. Documentation cannot be treated as a handover exercise separate from the technical work. It is part of demonstrating how the solution was developed, reviewed and delivered.
WHERE WE ADD VALUE
The most difficult passive fire issues are rarely solved by one discipline working in isolation. They require the fire consultant to understand the design intent, the architect and engineers to understand the construction interface, the specialist contractor to understand what can physically be installed and the wider project team to understand what evidence is required to demonstrate compliance.
Our role is to bring those parties together and maintain control of that process. Whether we are coordinating a standard service penetration, resolving a non-standard drylining junction, reviewing a fire-door interface, managing an engineering judgement or attending a physical burn test for a bespoke detail, the principle remains the same: identify the condition early, establish the evidence required, coordinate the solution and close the technical loop before it becomes a site issue.
That is how passive fire protection moves from a line on the fire strategy to a coordinated, evidenced and buildable part of the completed building.
At Hot Pickle Consulting, we build that approach into our process from pre-construction through to handover. We have extensive experience in coordinating non-standard passive fire protection details, establishing appropriate routes to technical acceptance.
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