Hi,

I am getting more and more passionate about fire safety regulations, especially on fire rated doors, also thanks to this forum.

I am trying to understand more about why gaps are so important and how they were determined.

For example

- why 10mm gap is allowed at the bottom but only 4mm on the sides and on top?

- why 5mm would fail? What's the difference with 4? That smoke seals are only 4mm or because flames would pass in 5mm but not in 4?

- why 2mm is ok but less it's not?

 

Thank you for helping me in understanding more. Could you suggest a good course or certification on these matters?

https://www.firedoorscomplete.com/training-qualification We would be please to help.

thank you!

It would be great if anyone could answers my questions, worst case I will learn at the course!

After looking more into gaps I'm a bit confused. It doesn't seem like those 3+/-1 mm are a legal requirement, they are "recommended". Is that true?

Referenced in BS 8214: 2016 Timber-based Fire Door Assemblies: Code of Practice  https://knowledge.bsigroup.com/products/timber-based-fire-door-assemblies-code-of-practice/standard but not necessarily a legal requirement

As Neil says the BS isn't explicitly a legal requirement, but would probably be cited by prosecution & used by the Magistrate as reference to a standard that would meet the requirements of the legislation - you would need to show why not following this still provided adequate protection & thus no risk of serious injury or death to relevant persons

Very few things in detail are explicit in the actual legislation, which sets broad functional aims, however many are implicit requirements, the onus being on the Duty Holder to show that an alternative approach would still equate to a suitable standard of safety.