Hi Iv recently won a contract up grading the iron mongary and fire/smoke seal on old fire doors. I know the gap has to be 3-4 mm but a lot of these doors have a decent leading edge on them. Will this fail the door? as it makes the door stop side edge over 4mm when the door is shut.... also if the 8mm hard wood edging has been completely planed through does this affect the integrity of the door? 

Thanks chudy 

Suggested sources for information to help:

The 'Code of Practice: Hardware for Fire & Escape Doors' http://firecode.org.uk/Code_of_Practice_hardware_for_fire_and_escape_doors.pdf

Intumescent Fire Seals Association  www.ifsa.org.uk 

'BS 8214 : 2016 Timber Based Fire Door Assemblies Code of Practice'  https://shop.bsigroup.com/ProductDetail/?pid=000000000030332501

'Timber Panelled Doors & Fire' https://planning.islington.gov.uk/NorthgatePublicDocs/00243092.pdf

With regard to planing through lippings, I don't know of any 'lipped FD30 or FD60 timber fire door' that permits planing-through. Usually a 6mm retained thickness is required. The website https://www.falconpp.co.uk/technical/ provides access to technical manuals for a number of fire door leaves and deals with lipping of fire doors.

Access to Certifire data sheets for certificated timber based fire doors https://www.warringtonfire.com/certified-companies 

BWF Certifire best practice guides https://firedoors.bwf.org.uk/publications/guides-and-directories/

I'm enquiring regarding old style doors without current markings smoke seals or intemicent strips but are of a solid construction and are inline with the aesthetics of the building.

would all this type of door need to be replaced or can they be upgraded to comply?

You would need to seek advice from a competent fire door upgrading contractor or fire door inspector.  There's a variety of fire door upgrading products on the market but not all doors are suitable for upgrading.