Under-stairs electrical cupboard in block containing 2-Flats. Can I fit a stainless steel mortice rack bolt as the security device on the FD30 rated fire door?

So the door will be a FIRE DOOR KEEP LOCKED and kept locked at all times. The door should be fitted with a fire rated mortice lock and a 'Fire Door Keep Locked' sign to the outside. I assume the door is made from timber based materials.

The document 'Hardware for Fire & Escape Doors' at http://firecode.org.uk/Code_of_Practice_hardware_for_fire_and_escape_doors.pdf provides the information you need on pages 60 to 68.

Neil,

Many thanks for your prompt response to my query.

My only concern is that in our Development there are 5 of these doors and it's proving difficult to find reasonably priced 5x keyed alike 3-lever mortice locks. The advantage of rack bolts are that they are cheap, easy to fit and one key fits all. The doors are in hallways with no public access and only 2 or 4 flats, so security is not an issue - especially the doors would only need to be opened for fire inspections!

I was hoping that if rack-bolts were installed in the same manner as fire rated tubular latches that this would be OK, especially as the key hole would only penetrate the outer skin of the fire door. 

My understanding is that the doors are FD30s fire resisting doors. Are the rack bolts compliant with paragraphs 6.2.2 and 6.2.3 on page 61 of the document 'Hardware for Fire & Escape Doors' ?