EDITOR ' S CHOICE
FIRE TESTING AND THE ROAD FROM BS TO EN
In recent years, the UK construction sector has moved from historic British Standards( BS) toward European( EN) test methods and classification systems as part of the process to strengthen fire performance standards and legislation. This transition creates a more structured framework for demonstrating performance, with clearer links between what is tested in the laboratory and what is ultimately installed on site. True assurance depends not only on how products are tested, but on how results are interpreted and how far those results can legitimately be applied.
TRANSITIONING FROM SINGLE TEST RESULTS TO DEFINED APPLICATIONS
Historically, fire testing has been conducted as a oneoff event: build a sample system, test it, record the result. The difficulty came when applying that result to products of different sizes or configurations. The boundaries were not always obvious.
The transition from historic BS 476 methods to BS EN test standards and classification systems addresses this. It builds rules for practical application directly into the framework of standards, so performance can be fully defined and traceable.
The results of a fire resistance test such as BS EN 1364-1( which replaces BS 476-22) determines the tested system performance to BS EN 13501-2( for example EI 240 – 240 minutes integrity and 240 minutes insulation fire resistance). However, this classification is just the start.
DIRECT FIELD OF APPLICATION( DIAP).
DIAP rules are written directly into the test standard. They define specific, limited variations that are automatically covered by the test result without further assessment. Depending on the standard and construction, DIAP may permit defined adjustments such as reductions in size, increases in certain component thicknesses, or dimensional changes permitted by the test standard. DIAP provides a clearly defined starting point. It ensures that every test comes with an inherent, published scope of application.
EXTENDED APPLICATION( EXAP).
EXAP standards provide a structured, rulesbased method for extending fire test results using recognised technical principles. EXAP is carried out in accordance with the relevant EXAP standard, which may be supported by:
• EN extended application standards
• European Assessment Documents( EADs)
• Relevant European Commission Decisions or delegated acts
• EN 13238( conditioning procedures)
• CEN / TS 15117 and other sector-specific technical specifications
The process typically follows one of several recognised methods:
1. Direct reference to product technical specifications where extension rules are already defined
2. Relationship-based assessment, demonstrating how performance varies with defined parameters
3. Experimental or empirical programmes, using additional test evidence to map performance changes
4. Recognised calculation methods where validated models are available
The objective is to ensure that any extension remains technically justified and consistent with established European methodology.
The pathway from test to classification The overall process can be visualised as:
The final classification report records not only the fire resistance performance, but also the permitted field of application derived through DIAP and any applicable EXAP.
At Attain RTC, we work within this framework every day, delivering EN fire testing and supporting clearly defined DIAP and EXAP pathways in line with current standards. Our UKAS-accredited laboratory was developed specifically for this more structured testing environment. By combining state-of-the-art equipment with technical expertise and well-defined processes, we focus on producing evidence that is robust, traceable and aligned with today’ s regulatory and compliance landscape.
In a system where assurance depends on the quality and clarity of the underlying evidence, our role is to provide reliable testing and technical support— helping turn fire test results into performance information that can be confidently understood and applied across real projects
• EN product standards www. cagroup. co. uk
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