Put simply, EXAP stands for extended field of application. These are the only EN standards allowed to go beyond the fire test standard to extend the number of 3rd party approved applications.

Why EXAP and why now?

In 2018, the Hackitt report triggered changes to Approved Document B. The changes meant that products and systems for fire resistance are tested against EN standards; that only extended (EXAP) or direct (DIAP) application rules can be used to extend results; and that official classifications to EN 13501-2 should be provided. It also states that all these tasks need to be conducted by approved 3rd party bodies.

The strict extension rules in an EXAP standard mean that certain criteria must be met to increase height or change components.