Update on Water mist Standards: BS 8458 and BS EN 14972-17

BS 8458 has now been withdrawn and replaced by BS EN 14972-17. This change brings water mist systems under a single European “Family of Standards,” which the UK is required to follow as a member of the European Committee for Standardization (CEN).

What does this mean?

• The fire tests within BS EN 14972-17 are the same as those previously used in BS 8458, including:
  • Corner fire tests
  • Beneath nozzle tests
  • Ventilation tests
  • Between nozzle tests
• Currently, only one UK test house is accredited for BS EN 14972-17 testing. The Fire Protection Association (FPA) gained UKAS accreditation at the end of 2025, and iMist is first in the queue when testing commences.

Existing projects and approvals

Projects that were previously approved under BS 8458 remain valid. Any requirement to upgrade to BS EN 14972-17 is at the discretion of the Authority Having Jurisdiction (AHJ).

This means that in most cases, existing certified systems can continue to be used and recognised.

About BS EN 14972

BS 8458 was the standard for water mist. It was a single document made up of design, installation, maintenance and testing guidance.

The new BS EN 14972 Series is multiple documents, each providing guidance on different areas:

Part 1 – Design, Installation and Maintenance

Parts 2-17: Fire testing for different occupancies/hazards

Our certifications

You can view iMist’s current accreditations and certifications here.

Statement from BSI

Prior to the release of BS EN 14972-17, BSI issued the following statement:

“BS 8458:2015 will be withdrawn at the same time EN 14972-17:2025 is published…
As a non-harmonised European Standard, there is no legal obligation for EN 14972-17:2025 to be used unless imposed by statutory or regulatory bodies…
It should not be inferred that products or certification schemes developed to BS 8458 can no longer be used or recognised.”