One hour fire door and frame query

[Davo]

A bit of technical help. please

Should a one hour fire door always be supplied as a set or can the frame be made seperately?

http://s690.photobucket.com/albums/vv266/DavoB/?action=postuploadshare

note the different timber for the top of the frame!


cheers

davo

[kurnal]

You are right to be cautious Davo. A frame for a one hour door will invariably be hardwood - that head looks like pine?

One hour doors should ideally be tested and supplied as a doorset with frame but I am not certain that this always HAS  to be the case. Certainly at 90 and 120 minutes this is true.

And certainly fabricating a one hour door frame needs to be done with great care. It is far more onerous than a half hour door.

[nearlythere]

Looks like even if they did and could make the door and frame up to 2 hours a fire could find plenty of other ways to flank around it.

[Davo]

Same topic, different query


New One hour doors being fitted to protected 9 storey stair with new dry riser has the usual twin strips but no smoke seals, should they be fitted? Building regs not clear, FRS designating stair as FF.
Doors supplied with frame into twin plasterboard on softwood battens.

Premises has 180 beds, occupants not always compos mentis due to on site libation.


davo


Prof

The other chap has been here also......

[kurnal]

Davo it is not straightforward and hopefully Auntie Lin will post something that will make more sense than the following:
The fire door designation in the UK ie FD30, FD60 stands alone - there is no test pass or failure criteria relating to the passage of smoke past the door under BS476 part 20 and 22. These tests measure integrity. A door will be given its integrity rating FD30, FD60 in its own right.
Smoke control is a separate factor. Many doors are required under Building Regs to provide resistance to the passage of smoke. This  is tested using the procedure in BS476 part 31.

So the answer is - taking into account the position and role of the doors, look at ADB table B1 and see if for the table lists these doors as requiring smoke leakage performance eg FD30S FD60S.

I think you will find they do if you are doing what I guess you are doing in the building that the other chap looked at.  I accept that it is difficult to interpret the need for smoke seals for firefighting shafts (especially improvised retro fitted firefighting shafts!) from table B1, if you have a copy of BS9999 you will find some diagrams in chapter 21 that are much clearer to follow.

[nearlythere]

Davo it is not straightforward and hopefully Auntie Lin will post something that will make more sense than the following:
The fire door designation in the UK ie FD30, FD60 stands alone - there is no test pass or failure criteria relating to the passage of smoke past the door under BS476 part 20 and 22. These tests measure integrity. A door will be given its integrity rating FD30, FD60 in its own right.
Smoke control is a separate factor. Many doors are required under Building Regs to provide resistance to the passage of smoke. This  is tested using the procedure in BS476 part 31.

So the answer is - taking into account the position and role of the doors, look at ADB table B1 and see if for the table lists these doors as requiring smoke leakage performance eg FD30S FD60S.

I think you will find they do if you are doing what I guess you are doing in the building that the other chap looked at.  

But fitting a smoke seal does not necessarily make them capable of preventing the  passage of smoke Kurnel. Making them fit neatly can which may require the provision of smoke seals.

[jokar]

Have they been removed for a pressurisation system?

[kurnal]

Great point Jokar you are absolutely right but unless Davos boss has very deep pockets I am sure that is not the case. I understand this to be remedial works on an existing building.

[Davo]

Thanks Prof

9999 show the same diagram as DocB but now adds commentary about the doors in that seals are now required!
(This now agrees with B1!)


Jokar, due to lack of finanaces, all non-substantials will not be done for two years. When you factor in 135 premises this adds up to an awful lot. The powers that be call this risk management, apparently )

cheers

davo

[Tom Sutton]

Davo what they doing is to limit the ingress of smoke into the escape route (A ff staircase is also an escape route) or they could restrict a fire and remove the smoke. They need to do this to meet Regulation B1 see Performance para e in ADB vol 2  page 16. I would suggest fitting smoke seals and/or AOV or pressurization would meet that clause.

You have discount pressurization and aov I guess so you are only left with smoke seals.

[Auntie LIn]

Blimey chaps - few days off the Forum and you find me all manner of questions to answer!

Davo - you will find much greater emphasis on doorsets now, as a prelude to CE marking (apparently you can't mark components, but you can mark a hinge.   What's a hinge if not a component?.   At the moment under E&W regs you are not obliged to fit sets but if you are not fitting pre-hung sets it's vital to follow the manufacturer's instructions about what to use.   If he says an ex-100x 40 hardwood frame 650kg/m3 density or above then that's what should be used.   Sadly, too many 'fitters' think wood is wood is wood - hence you get them using whatever comes to hand.   There are some doors that have been tested with softwood frames, but these are very few and far between and rely heavily on both the specification of the frame and things like gaps. Certainly you should never pick & mix timber for frames.

Picking up on one of Kurnal's comments - like so many things in British Standards we have no definitive pass/fail criteria for smoke control.   In the days when BS5588 was king, they actually wrote an amendment to some of the sections to set a limit on smoke leakage.   Can't find my 5588s to check the details but I think it called for leakage not to exceed 3cu m/hr/m of leakage path when tested to BS476:31.1 at a pressure of 25Pa and with the threshold taped.   Sounds dead quaint, I know, but the reasoning was that under smoke test conditions, the pressure was constant across the whole height of the door, while under fire conditions you get a higher pressure at the head and this reduces so that somewhere between latch height and 1/3 height you're reaching a neutral pressure and from there on down it goes negative.   The effect of taping up the threshold was to try and make some sort of allowance for this diminishing pressure.

Nearlythere's right that smoke seals won't necessarily make them resist the passage of smoke.   Fit of the door is everything.  A really well fitted door with smoke seals stands a good chance of working.   One that's been thrown into its frame on a Friday afternoon, after a liquid lunch really doesn't stand much chance at all however good the seals were when they were put on.