Any claim of fire resistance in a construction product (as under the Construction Products Regulation (CPR)) must be backed up by proof of extensive testing and examination that demonstrates its
compliance with the relevant UK or European
standards.
It all starts with primary fire and smoke testing
A Conformity Assessment Body (UK Approved Body) classifies fire-resisting products in line with EN 13501 and standardised technical procedures. Certification is underpinned by primary fire and smoke testing, which defines its exact application, or Direct Field of Application, known as DIAP.
DIAPs are strictly limited to the specification of the tested sample, including its size and specific hardware configuration. The doorset sample tested will be of a certain size, with specific hardware, fitted in a certain configuration. With all these details recorded, the resulting report often runs to hundreds of pages!
A successful pass enables the conformity assessment test lab to declare a Direct Field of Application; there is primary evidence that this particular doorset’s design, specification, and construction meet the standard (eg EN 1634-1).
However, this single test alone only provides a very narrow scope, demonstrating the reaction to fire of this exact configuration and dimension. What about different sizes or hardware configurations, even those that would improve resistance to fire and smoke? Many real-life scenarios call for variations, from retrofitting old buildings with modern fire doors to meeting case-specific environmental or security performance standards.
This is where Extended Fields of Application (EXAP) come in, enabling third-party assurance that the original fire-performance characteristics aren’t compromised.
What is EXAP (“Extended Field of Application”)?
EXAP is a formal process defined in recognised standards (see below, ‘How EXAPs are overseen’) that enables an approved technical assessor to extend a certificate’s field of application (DIAP) based on known, verifiable information. It covers minor variations of a product or system, such as sizes, glazing options, or hardware features, without re-testing every single combination.
EXAP – Maintaining safety across every application
An important point to stress here is that EXAP is designed reduce the amount of
re-testing – which would impede the development of new and improved fire safety products for no practical reason. Following relevant EN or ISO standards, the assessor makes calculated decisions on extending the scope of certification. Technical assessments, engineering analysis, and verified knowledge of material performance are used to justify the EXAP report.
Loose examples of EXAP could be extending certification to cover a fire-rated door that has a smaller glazed viewing panel than the design that was tested, or uses a 60-minute door closer on a previously tested 30-minute (E30) fire door. Suppose the examiner can show justification that the variation would not reduce the doorset’s fire-resistance below the designated rating (E30). In that case, they can extend – “without further testing” – the field of application to cover this variation.
How EXAPs are overseen
To ensure technical rigour and consistency in applying engineering judgement across certification bodies, EXAPs themselves are governed by a dedicated range of EN standards.
BS EN 15269 is a series of EXAP rules that formalise the decision-making process for fire doorsets, fire-resistant hardware, and shutters that the examiner must take.
Additionally, even the format of the EXAP report has its own standard – EN 15725.
With the removal of BS476 from Approved Doc B in 2029, EXAPs are likely to become more important to door manufacturers who tested to the legacy standard, as they move over to the sole use of the EN equivalent.
EXAPS are designed to remove ambiguity and unnecessary cost in achieving a wider scope to certification. The Government’s aim is to help maintain safety standards while enabling innovation, a wider range of consumer options, and a healthy supply chain for fire-rated construction products.
Rutland helps door manufacturers increase their range of approved hardware options.
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