Stud opening size for fire doors and lining

[ivanfabian]

Hi all.

I need to fit two 1981x762 (6'6" X 2'6") fire doors (FD30). I don't yet have the door and lining so don't have anything to measure off to make sure I get the opening wide enough. I've fitted normal doors and linings before but not done a fire door. Just because I want it done right first time I'll get someone qualified to do that part for me.

I have two doors that I need to prepare the opening for. One will be in a stud wall that I will build the other is in an existing brick wall where I am expecting to raise the lintel and also widen the opening. The wood floor will be carpeted.

The questions are how big must the opening be width and height. Is a FD30 lining different from a standard softwood internal door lining. How much do you add for carpet when a fire door is fitted. Is a special threshold strip needed with a fire door.

Thanks everyone. I look forward to any advice hints or tips.

 

[baldkev]

They are often 30 to 32mm thick.... so door width plus gap ( usually set by the pre trenched head at about 4mm ) 2 thicknesses of jamb ( say 64mm ) plus wedging space. I like 12mm per side for folding wedges..... that should be safe. Height depends on floor levels and finished floor ( carpet / vynil / tiles etc )

 

[JobandKnock]

The gap has to be 2 to 4mm round three sides with a maximum of 4mm gap at the bottom to to floor at any point when the door is closed. Any more than 4mm and you should fit an automatic drop seal, eithervrouted into the door bottom or face fixed. A fire door should not have carpet on the floor beneath it. Packers must not be nearer to the edge face than 10mm on one side (FD30, FD60 it's both sides) and that 10mm set back should be filled with intumescent caulk - in other words beneath the architrave on one side of the door opening (both sides for FD60). Gaps between door casing and opening should be packed with mineral wool if the gap is 10mm or greater, or fully caulked with intumescent caulk if the gap is less than 10mm. This is basically the standard we've been required to work to in public buildings for a few years

 

[Garden Shed Projects]

The fire doors I am currently installing have frame thickness of 30mm plus a 10mm gap for foam/ mastic.
Apolgies for metric calc. 2’6” is 750mm plus 2x3 mm gap plus 2x30 mm frame plus 2x10mm mastic is 836mm. Height will be 6’6” is 2m plus 3mm plus 30mm plus 10mm plus carpet thickness, say 12mm, is 2043mm. Frame thickness is the thing you will need to confirm.
Hope this helps.

 

[Garden Shed Projects]

The fire doors I am currently installing have frame thickness of 30mm plus a 10mm gap for foam/ mastic.
Apolgies for metric calc. 2’6” is 750mm plus 2x3 mm gap plus 2x30 mm frame plus 2x10mm mastic is 836mm. Height will be 6’6” is 2m plus 3mm plus 30mm plus 10mm plus carpet thickness, say 12mm, is 2043mm. Frame thickness is the thing you will need to confirm.
Hope this helps.

I agree with jobandknock regarding carpet under doors. You will need a threshold as Max gap allowed beneath is 4mm. If the door opens across the carpet you should make allowances when setting the height of the opening.

 

[Garden Shed Projects]

Google “Blue60 fire foam” for gap filling. Generally fire foam looses it’s integrity when you cut back the crispy shell for architrave. This stuff lets you cut it back with no loss of integrity and doesn’t require capping off with mastic.

 

[ivanfabian]

That's really useful advice. Thanks very much. It seems like all I need now is to be sure of the lining thickness then I can work it out from the numbers you have given. So no carpet under the closed door but I still have to allow for it in the door swing of course and make sure the closed under door gap is right. Thanks again.

 

[LeeAkeroyd]

We normally trench fire door heads at door width +6mm (allows 3mm each side) for a single door. For a 762mm door using a 32mm thick lining would give an overall width of 832mm or if a 30mm lining is sufficient then the overall width would be 828mm.

Before ordering your lining check the fire door certificate as this will tell you the minimum dimensions permitted.

 

[hairy]

So domestic fire doors from new should always have a threshold under to allow for any future floor covering that may go under the door opening? Didn't know that.

 

[JobandKnock]

Not really. If the property is sold with laminate flooring (fairly common) you just ensure that there is a 4mm gap beneath it!

 

[owen]

Can have more than a 4mm gap underneath on most, normally 8-10mm if I remember correctly.

 

[JobandKnock]

AFAIK 10mm is the maximum gap on a basic fire door (the type which has a flat intumescent strip, e.g an equipment room or riser) whilst 4mm is gap on a smoke control fire door where a cold smoke seal intumescent strip is required. At least that's the standard we have to work to

 

[JobandKnock]

Gets even more complex when you have to take fire exit doors into consideration. Maybe the question to ask is what the architect has classed the OPs door(s) as

 

[Chippysu]

Hi all.

I need to fit two 1981x762 (6'6" X 2'6") fire doors (FD30). I don't yet have the door and lining so don't have anything to measure off to make sure I get the opening wide enough. I've fitted normal doors and linings before but not done a fire door. Just because I want it done right first time I'll get someone qualified to do that part for me.

I have two doors that I need to prepare the opening for. One will be in a stud wall that I will build the other is in an existing brick wall where I am expecting to raise the lintel and also widen the opening. The wood floor will be carpeted.

The questions are how big must the opening be width and height. Is a FD30 lining different from a standard softwood internal door lining. How much do you add for carpet when a fire door is fitted. Is a special threshold strip needed with a fire door.

Thanks everyone. I look forward to any advice hints or tips.

I was informed a couple of years back that all new door linings now have to be fire rated too. Although the dimension thickness I've seen stocked are still 32mm. I was wondering about the threshold gap and swing, if the floor is out of kilter & the door with 4mm under gap then scrapes floor instead of increasing said gap are there such a thing as fire rated rising but hinges?

 

[Corset]

As a letting agent thios is a daily consideration. The fire doors rating is affected by the material is composed of and its use. The application of varius seals affects its rating in the property. ie if the door is for House in multiple occupation the alarm system dictates the type of strip. Ie if the room has a smake alarm and sounder the door with a have a cold smoke seal and intumescent strip. If it has no alram it will need just an intumescent strip. If the seal is cold strip the the rebat must be a certain size and the gap no greater than 4mm. The rating of the door will actually be varied by the seals used and i believe the door is generally an fd30 (30mins) but the addition of the seals and the type of frame will raise this to fd60. The thickness of the door is irrelevant if it has a rating as there are thin profile fd30s and the more standrd 44mm. I am not an expert but factrors such as alrmas hinges, closures etc all play into the spec. Commercial will be different to residential. not sure if that helps.. Building regs and lacors (domestic fire regs for rented property) will be your friend here. Some flats have additional floor seals that need to be incorparated for additional measures.....

 

[JobandKnock]

I was wondering about the threshold gap and swing, if the floor is out of kilter & the door with 4mm under gap then scrapes floor instead of increasing said gap are there such a thing as fire rated rising but hinges?

If there is I've never seen them! What you often need to do is fit an intumescent drop seal to the door, either let into the bottom edge (I.e routed, now you know what that weird Festool jig is for) or surface mounted on the inside face of the door. The latter is more common in retro fits

To answer your other query, 30 minute fire door casings are generally softwood (although I have seen MDF) whilst 60 and 120 minutes are normally hardwood (but I have seen a few softwood ones). FD60 rated casings have a deeper stop /rebate than FD30 in my experience

 

[LeeAkeroyd]

If there is I've never seen them! What you often need to do is fit an intumescent drop seal to the door, either let into the bottom edge (I.e routed, now you know what that weird Festool jig is for) or surface mounted on the inside face of the door. The latter is more common in retro fits

To answer your other query, 30 minute fire door casings are generally softwood (although I have seen MDF) whilst 60 and 120 minutes are normally hardwood (but I have seen a few softwood ones). FD60 rated casings have a deeper stop /rebate than FD30 in my experience

As far as I'm aware no FD60 frame should be made from softwood. If you ever come across any in service I'd implore you to raise the concern with the relevant person to investigate if softwood meets the requirements of the fire door certificate.

 

[LeeAkeroyd]

As a letting agent thios is a daily consideration. The fire doors rating is affected by the material is composed of and its use. The application of varius seals affects its rating in the property. ie if the door is for House in multiple occupation the alarm system dictates the type of strip. Ie if the room has a smake alarm and sounder the door with a have a cold smoke seal and intumescent strip. If it has no alram it will need just an intumescent strip. If the seal is cold strip the the rebat must be a certain size and the gap no greater than 4mm. The rating of the door will actually be varied by the seals used and i believe the door is generally an fd30 (30mins) but the addition of the seals and the type of frame will raise this to fd60. The thickness of the door is irrelevant if it has a rating as there are thin profile fd30s and the more standrd 44mm. I am not an expert but factrors such as alrmas hinges, closures etc all play into the spec. Commercial will be different to residential. not sure if that helps.. Building regs and lacors (domestic fire regs for rented property) will be your friend here. Some flats have additional floor seals that need to be incorparated for additional measures.....

A FD30 and FD60 doors are completely different animals, you can't make a FD30 perform as a FD60 by adding seals.

 

[JobandKnock]

As far as I'm aware no FD60 frame should be made from softwood. If you ever come across any in service I'd implore you to raise the concern with the relevant person to investigate if softwood meets the requirements of the fire door certificate.

Never fitted any myself, but I am aware of one project where they were used. They apparently did pass a burn test but were also made from a fire reltardant treated timber and sdfitionslly needed to be finished in an intumescent lacquer to satisfy the insurance company and the fire authorities

 

[Corset]

yes my apologies, the door rating is linked to its testing and an fd 60 will not be the same as a fd30. However its end rating in us will be determined by its frame seal hinges etc. So plonking a fd60 door into a frame with the wrong hinges, rebate and seals etc will not give a better fire rating than a properly fitted fd30. If that makes sense.