[Internal fire door facing communal stairs]

Hi, I was hoping that you could help with some questions regarding fire doors in a residential property.  I am changing my front door, which is situated internally between my flat and a communal hallway.  They apparently have to be fire doors, and my query is to what actually constitutes a fire door.  I know that it needs to hold back fire for a min of 30 minutes, but would that include something like an old solid wood door for example?  I'd really like an old door as opposed to a new one, but am unsure as to whether it would qualify.  Any help you can give would be much appreciated, thank you.