How do I know if an interior door is a fire door?

[jumbob]

I'm looking to replace an interior door with a new door that is more aesthetically pleasing but am unsure if the existing door is a fire door. How would I tell if it is?

The existing door is 45mm thick and has three hinges with 15 panes of steel re-inforced glass, although there is no auto-closing mechanism and no markings on the top or bottom to indicate any special type of door. There is also no intumiscent on the door or the frame.

 

[^woody^]

The door may have a small, coloured plastic disc near the top hinge

Most modern doors will have a tamper-resistant label on the top edge - BWF-CERTIFIRE from the BWF - www.bwf.org.uk

From your description the door is a fire door, but the doorset (whole installation) is not up to todays standards

Domestic fire doors are normally only in flats or on houses of three-storeys or more and on certain rooms.

 

[r896neo]

only one way to find out!

 

[JohnD]

door is 45mm thick and has three hinges with 15 panes of steel re-inforced glass

and I expect it is surprisingly heavy. So yes it is

anyway, you decide if you need a fire door regardless of what sort the old one is.

glazed fire doors are incredibly expensive if they use unwired fire glass