Some planning and fire authorities require Intumescent fire and smoke seals to be fitted to the top and sides of the door.
They may also want door stops to be 25mm thick. Some form of door closer will be required.
Please remember that the hinges have to be up to a suitable fire standard.
Be careful to find out if a 30 minute or 60 minute rated door is required.
More info available at this page on DirectDoors.com
Fire doors at www.DirectDoors.com
Info supplied by www.directdoors.com