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What does the “field of direct application” for a product mean?

The field of direct application (DIAP) sets out minor variations which are allowed to be made to a product or how it is used, compared with the specific design/sample that was tested, under a product certificate. DIAPs are commonly used in key product testing standards, including fire resistance standards such as BS EN 13501-2: 2016.

Why are field of direct application variations included in product standards?

Regulators recognise that testing every possible variation of a product or system can be impractical. The DIAP provides a formal and transparent process through which minor changes can be made to the specific design/product that has been certified without requiring additional assessments or testing.

What variations may be allowed by a DIAP?

Acceptable variations may include changes to:

  • wall height;
  • wall thickness;

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  • product thickness; and/or
  • number of fixings or fixing centres.

    • The DIAP for a product will be set out in the testing classification report and will be specific to the design/sample that was tested. In some cases, variations may only be possible if the design/sample has achieved a specified level of performance in testing. It is therefore essential to refer to this report to confirm both the tested design and what variations are allowed. 

    What is the difference between DIAP and EXAP?

    In some cases, testing standards may allow more significant variations to be made from the tested sample/design. These will be set out in a separate Extended Field of Application (EXAP) standard. As the variations under a EXAP are more extensive than under a DIAP, they can only be made on the basis of a formal assessment by a qualified technical assessor.

    For details of Kingspan Insulation's fire resistance testing, including field of direct application for specific tested systems, please visit our fire resistance page.

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