I could do with some advice on fire resistant glazing, specifically, how do you test existing glazing panels in a fire door to assure yourself it is fire resistant and not replaced with normal glass at some point in its life?

I am faced with this situation with a client requiring assurance and I cannot find any identification marks on some glazing panels.

Advice gratefully received.

As you stated all fire resisting glazing should have identification marks in the corner.

Have you visited Site yourself and sure there are no stamps on the glazing? The reason I ask is that I have visited a few Sites that did not have identification stamps but they actually did and they were just faint. Maybe the stamps are hidden by the beading?

No real way to test if it is fire resisting when it is insitu. The clear fire resisting glass is generally laminated (But with different interlayer) so it could look like thick shopfront glass.

Sorry cannot be much more assistance - I would raise this with the door supplier.

Thanks for the above everyone. The document above is very useful and I had not seen that before so thanks a lot firesafetybod!

In essence and for future reference, the glass panels should have a visible mark even after glazing in place.

As we cannot see this in some locations, we're going to have to review all CDM files for as built standards, any evidence of repair works undertaken by FM provider and possibly remove the relevant panels and replace..... !