fire doors are 44mm thick
Actually, John,
30 minute (FD30) fire doors are
normally 44mm thick, 1 hour (FD60) fire doors are generally 50 to 52mm thick, but other specs are manufactured and available. The sticker on the top of the edge of the leaf, or the coloured plugs in the same place indicate the actual fire rating,
NOT the thickness . It is important to fit a door with the appropriate rating.
For maximum sound resistance, seal it to the wall with pink fire-foam injected into the gap, and fit the intumescent strips with a furry brush-pile.
In point of fact so-called fire foam is AFAIK no longer permissable on its' own in a multiple residency property and the building may well have a document stating what is the minimum requirement (which would be in the possession of the duty holder/landlord/lease-owner). For a 30 minute fire rating this may be 10mm of intumescent sealant beneath the architraves on one side (with the packers cut back 10mm from the surface) and either mineral wool or fire foam beneath that. In the case of 1 hour doors this is doubled-up with 10mm depth of intumescent sealant
on both sides in addition to which it is generally a requirement for the hinges (class 11 or 12 fire rated, normally stainless steel, ball bearing - also required on FD30 doors) to be fitted with intumescent hinge pads and for locks and keeps to be wrapped with
intumescent paper and fire rated door closers (also required on all fire doors in multiple occupancy buildings) to be insulated from the door by a combination of intumescent paper and intumescent sealant. There is also a requirement that the gapping around the three sides of the door be between 2 and 4mm
ONLY (generally checked at 3 to 4 points per side using a taper gauge or brake calliper gauge) and that the gap at the bottom of the door be no more than 4mm at any point when the door closed. If it is more than that then an
intumescent drop seal which meets this requirement must be fitted. This may even mean relevelling the door threshold area if the floor in not flat enough.
The
"intumescent strips with a furry brush-pile" are combined intumescent strips and cold smoke seals and there are also types with rubber "wiper blade" seals available these days (often used in hospitals). Helps when asking for these things if you know the proper terminology I find
BTW these regs aren't new - they came into force in
2006 and seem to be generally ignored by certain domestic and small scale builders. Where I often work (in commercial/public buildings) they are often being rigorously enforced, and even more so after Grenfell. TBH I find that the average joiner I work with is also completely ignorant of what they are required
by law to do when installing fire doors (and yes, I'm a joiner, too, although I also hold a fire door inspection ticket, hence the long response)
Fire doors are very dense and heavy, and good for blocking sound. Being thick, they will take a mortice lock and/or a nightlatch. However they are usually unglazed. Fire-resisting glass is very expensive. Georgian wired glass was formerly used, I don't know if it is still acceptable.
Locks need to be wrapped, as stated above. Night latches are generally very poor in fire doors and ideally should be avoided due to the large void (hole) in the door needed to install them. Glazed doors need to have been tested as such and supplied with the glass fitted (or it can be fitted on-site by the supplier) - you can no longer convert a door on site as that doesn't meet the regs, just as you are given limited leeway on trimming doors to fit openings (manufacturers tend to quote 2 to 5mm trim allowance in my experience). As to Georgian wired, that is no longer permitted (the wire transmits heat through the door) - it is now often replaced by either appropriate fire-rated DG units in intumescent seals or pyro glass, again with appropriate intumescent seals
You can easily get a panelled solid fire door. Due to the weight I strongly recommend hanging it on three lift-off hinges. paint-grade ones are much cheaper than veneered.
Panelled doors need to be specifically fire tested and rated - most aren't. The majority of lift off hinges are most definitely NOT fire rated and must never be fitted to a fire door - doing so will nullify the fire rating of the door. The only permissable hinges on fire doors are now fire rated ones - which are generally stainless steel or in some cases brass or bronze and are invariably ball bearing types (see above)
Sorry, John, but your understanding of fire doors is 15 years or more years out of date. To update yourself why not have a read of
this page on the Fire Safety Advice Centre web site which explains the salient points. There's a lot there, but I felt that you original response really warranted some correction and updating, and I hope that you'll find it informative
