FireNet Community
FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Fire Safety => Topic started by: Tom Sutton on January 31, 2008, 04:01:47 PM
-
Loft conversion, all doors upgraded to 20/30 FR doors. Original doors had 2 X 3 inch steel hinges do they need to be replaced with 3 X 4 inch hinges or is this overkill? Also does BS EN 1935:2002 answer this question fully.
-
tw
BS8214 recommends 3 X 4 plain knuckle butt hinges.
Presumably the upgrade was in accord with the several guides floating about in cyberspace?
davo
-
You have to understand why 3 of 4 ins hinges is recommended in the first place. When the door model was tested the manufacturer ensured that, for the sake of a few pounds, it passed the acid test, whether it needed it or not, with intumescent strips, smoke seals, a third hinge and bigger than normal, intumescence on the hinges, 25mm door stops etc,etc.
I have no doubt that had there been a lump of chewing gum inadvertantly stuck to the door during the test that would now be regarded as a key component of a fire door.
Thing is nobody is going to pay to have a fire door tested without, for example, a 3rd hinge, which only costs a few pounds, to see if it satisfies the standard. No point really. Why spend thousands to see if you can save £10.
This then means that many inspectors or assessors do not accept a fire door without the 3rd hinge or without the smoke seals etc.
-
Is it a single private dwelling or HMO?
If private dwelling was the loft conversion started before or after 6 April 2007?
Are we talking doors to rooms lining the staircase or the door separating the new storey from the rest of the house?
For single private dwellings rooms, prior to this date the ADB allowed retention of existing doors and asked for rising butts or self closers, after this date 20 minute fire doors without self closers.
For HMO it will need the full monty.
-
tw
BS8214 recommends 3 X 4 plain knuckle butt hinges.
Presumably the upgrade was in accord with the several guides floating about in cyberspace?
davo
Davo
Could you give more details, unfortunately I do not have a copy and would like to pin it down. The doors are new doors, using 3 X 3 inch hinges which is not acceptable to the Building Inspector.
Kurnal
The conversion is a private dwelling and was started after last April, and provides 30 minute fire doors without closers. The doors are separating the existing inhabited rooms from the loft escape route (ie hall & landing).
-
Since the reuirement is for 20 minute doors - not 30- and there does not have to be a self closer of any description the building inspector could be accused of being rather pedantic. Three hinges are normally a requirement for fire doors both due to the weight of a fire door and to resist the warping that occurs when a fire heats one side of a door ( Though I always take that reason with a pinch of salt myself cos the door can be unsupported on the other side!!!)
Heres one of many typical useful webstes on the subject- most local authorities do similar- but look out as many have not yet updated since the change to Approved document B 6 April 2007.
http://www.swansea.gov.uk/media/pdf/d/l/Loft_Conversions_and_the_Building_Regulations.pdf
Later edit- on further reflection I guess logic would say that since it was the client who elected to install 30 minute doors rather than 20s, and since all 30 minute door sets are tested with three hinges it is reasonable for the inspector to require them.
-
TW
I have emailed you some of the the free stuff from Trada/BWF/ASDMA.
Cannot send you the BS as it is copyright, sorry
davo
-
Thanks to you all.
Kurnal I think it was more about other people telling him it was OTT and he decided to fight but now I think he will concede.
Davo Thanks very much, I have some of the docs you highlighted, but the others I will add to my list.
For the moment I will study BS in my local reference library but if my sponsors come up with the goods this year I will buy BS8214.
My main point was I have known for years that 3 X 4 inch steel butts are required for Fire Doors but when I was asked show me in black and white I was stumped.
-
Hinge requirements are generally as follows:
They must be either as tested or of a nominally similar size and pattern to that tested. The reason we test with 3 hinges is that the third hinge performs one of two functions - either when fitted at half height prevents the door from deflecting (bowing), or when when fitted with two at the top increases the load bearing capacity.
The reasoning behind 4" / 100mm butts and 3 of them is that smaller or less hinges will not carry the weight of the door.
-
Hinge requirements are generally as follows:
They must be either as tested or of a nominally similar size and pattern to that tested. The reason we test with 3 hinges is that the third hinge performs one of two functions - either when fitted at half height prevents the door from deflecting (bowing), or when when fitted with two at the top increases the load bearing capacity.
The reasoning behind 4" / 100mm butts and 3 of them is that smaller or less hinges will not carry the weight of the door.
Redbadge. Don't quite understand the bit "either when fitted at half height prevents the door from deflecting (bowing), or when fitted with two at the top increases the load bearing capacity".
When fitted with two at the top to increase the load bearing capacity then the door could bow as there is none at half height. And when fitted at half height to prevent the door bowing the load bearing capacity is reduced because there is only one at the top.
Why only one or the other and not both?
You commented that "we test with three hinges......" Are you in the door testing business?
-
The measurements of a hinges are now irrelevant, hinges should be selected by use, measurements of door and category in accordance with EN 1935:2002.
Timber doors fitted with door closers should normally use three or more hinges. Door manufacturers may recommend the use of only two hinges under special conditions, if experience allows demonstrating adequate performance of the door.
Door closers which include hold-open devices or a back-check facility can impose substantially increased stresses on hinges and their fastenings. Hinges of grade 12, 13 or 14 should be used with such closers. If three hinges are used the third hinge should be fitted approximately 200 mm below the top hinge, in which position it supports some of the additional outward bending moment exerted on the top hinge. Substantial fastenings are recommended for both hinges and closers in such situations to prevent loosening of the fastenings and possible damage to the door or frame as a consequence of such loosening.
Check out http://www.gai.org.uk/_img/pics/TechupdateMarch06.pdf for more info.
-
Nearlythere,
I am in the fire door industry. Hopefully to clarify about hinge positions....
When testing it's fairly normal to fit the hinge at the centre point in height to reduce distortion. As with most building components performance is "certified" by subsequent engineering assessments that extrapolate data gathered from various test specimens of the same construction, within these the third hinge location will be generally specified as "equispaced" (between the other 2) - unless there is specific test data to demonstrate that the hinge may be raised towards the top of the door, in which case the alternative location will be stated in the assessment.
Also bear in mind that different types of door construction behave very differently under test conditions. For example, a solid timber core (lamels faced with ply mdf or chipboard) will distort far more than a solid particleboard core which tends to stay fairly flat but has greater tendency towards shrinkage.
The type of construction also influences to type of intumescent seals use which perform in quite different ways dependent on chemical composition.
-
Nearlythere,
I am in the fire door industry. Hopefully to clarify about hinge positions....
When testing it's fairly normal to fit the hinge at the centre point in height to reduce distortion. As with most building components performance is "certified" by subsequent engineering assessments that extrapolate data gathered from various test specimens of the same construction, within these the third hinge location will be generally specified as "equispaced" (between the other 2) - unless there is specific test data to demonstrate that the hinge may be raised towards the top of the door, in which case the alternative location will be stated in the assessment.
Also bear in mind that different types of door construction behave very differently under test conditions. For example, a solid timber core (lamels faced with ply mdf or chipboard) will distort far more than a solid particleboard core which tends to stay fairly flat but has greater tendency towards shrinkage.
The type of construction also influences to type of intumescent seals use which perform in quite different ways dependent on chemical composition.
Thank Redbadge
Never thought that door hinges on fire doors could be a subject in itself.
-
It's just occurred to me that the whole of this subject could be viewed as irrelevant from one technical perspective...
When testing we often use a double swing doorset which automatically gives us approval for a single swing door, rather than testing both - which would cost twice as much, the point of this being that a double swing door is hung on a floorspring and restrained by a top centre - so no hinges at all!
-
My second and third paragraphs are direct quote from BS EN 1935:2002.
-
Nearly there/TW
On checking some of my docs-
ASDMA (Auntie Lin?) top & bottom 250mm from top/bottom, third hinge 200mm below top hinge.
CAE just says two towards the top
BS8214 is vague
ASSA says same as ASDMA but 250mm for third hinge
Don't get me going on intumescent under the hinges!
saddo uup't north
-
It's just occurred to me that the whole of this subject could be viewed as irrelevant from one technical perspective...
When testing we often use a double swing doorset which automatically gives us approval for a single swing door, rather than testing both - which would cost twice as much, the point of this being that a double swing door is hung on a floorspring and restrained by a top centre - so no hinges at all!
Thanks RB
That clears it up no ends.
-
Don't get me going on intumescent under the hinges!
saddo uup't north
Funny thing is I was just wondering what people think about the use of intumescent under the hinges and around the lock?
-
Don't get me going on intumescent under the hinges!
saddo uup't north
Funny thing is I was just wondering what people think about the use of intumescent under the hinges and around the lock?
Is that not the result of throwing everything at the door to ensure it passes the test first time? How much would be saved by leaving it out compared to a test failure and retest?
-
Intumescent under hinges:
Don't usually use it in 30 minutes tests, but always do on 60 minute as the likliehood of burnthrough is to great at this level.
Again assessments vary as to requirements i.e. if the construction has only been tested with intumescent pads then they must be included.
Similar situation for all recessed ironmongery.
It'll save a whopping 30p (ish) to omit the pads - so not really that great a consideration, and err yes we do throw everything at test specimens!!!
-
Intumescent under hinges:
Don't usually use it in 30 minutes tests, but always do on 60 minute as the likliehood of burnthrough is to great at this level.
Again assessments vary as to requirements i.e. if the construction has only been tested with intumescent pads then they must be included.
Similar situation for all recessed ironmongery.
It'll save a whopping 30p (ish) to omit the pads - so not really that great a consideration, and err yes we do throw everything at test specimens!!!
How much does it cost RB to test a door?
-
3 or 4k for FD or E 30, 5 or 6 for FD or E 60, you can usually squeeze a couple of specimens in as long as they're single.
From a developement point of view you'd probably need to do a minimum of 4 or 5 tests to get a meaningful set of approvals -
single and double doors with or without overpanels, single and double swing, with and without glazing etc etc etc
Typically 20 to 30k to develope a 30 minute design...
-
3 or 4k for FD or E 30, 5 or 6 for FD or E 60, you can usually squeeze a couple of specimens in as long as they're single.
From a developement point of view you'd probably need to do a minimum of 4 or 5 tests to get a meaningful set of approvals -
single and double doors with or without overpanels, single and double swing, with and without glazing etc etc etc
Typically 20 to 30k to develope a 30 minute design...
So my value for money blowlamp test could very easily take off then?
-
3 or 4k for FD or E 30, 5 or 6 for FD or E 60, you can usually squeeze a couple of specimens in as long as they're single.
From a developement point of view you'd probably need to do a minimum of 4 or 5 tests to get a meaningful set of approvals -
single and double doors with or without overpanels, single and double swing, with and without glazing etc etc etc
Typically 20 to 30k to develope a 30 minute design...
So my value for money blowlamp test could very easily take off then?
I have to confess that I have been discovered outside with a couple of blow lamps myself, purely for intellectual reasons of course
-
Why do different guide books mention different lengths of screw?
Keep it clean or funny, please!
Anyways, you would always fit intumescent when you look at the standard of some of the chippies nowadays.
-
Screws -
Generally the screws are supplied with hinges and are 32mm long which is adequte to secure them.
Moving away from fire performance a door has to perform other everyday functions, to mis-quote someone else "a door is always a door but only a fire door once".
Other tests exist which determine the mechanical durability of the leaf, and there are also other standards which are used to establish the crfedentials of a doorset in operational mode. When testing open close cycles the proprietry screws supplied with the hinges were found to be inferior in performance so specialised screws were used - not length but quality!!!
-
oops, posted before completing....
Intumescent will not detract from performance if it is fitted around / behind ironmongery provided it is the correct type - it's conceivably possible that using the wrong type can be problematic - a high pressure uni-directional seal in a substantial mortice could in theory push the face of the door away.
Also, too much intumescent can be as bad as too little so the seal dimensions must replicate that tested or approved.
There are massive performance differences on certain door constructions when differing seal compositions are used - so the base composition of the seal should also be established as correct.
-
Redbadge
Phewww........, seems to me someone ought to write a definitive spec for a fire doorset.
My library on fire doors runs to 20 documents and they all come from different angles.
I knew there were different types of intumescent from downloading some freebies from IFSA, didn't realise it applied to more than just frames/lips. The hinge stuff I have seen is red mainly pre shaped, the stuff in the frames mostly is white.
-
So upgrading a door set with products from such companies as Envirograph is fine as long as the door set the original test was performed on matches the door your upgrading... I guess it's better than nowt.
-
Davo,
the easiest way to tell what intumescent type you're using is to lick it (believe it or not) as they all taste different - don't ask how I discovered that.
"Interdens" is the best stuff to protect hardware as it exerts minimal pressure but expands muli-directionally a hell of a lot.
We use the pink substance for lining 60 minutes vision panels, although other systems have a white liner.
Generally (assuming it's not marked) a salty tasting white seal will be palusol based. A black one intercalated graphite. any others will be either mono ammonium phosphate or amonium polyphosphate.
Be careful of the less expensive products as they do not perform as well (surprise surprise).
-
Davo,
the easiest way to tell what intumescent type you're using is to lick it (believe it or not) as they all taste different - don't ask how I discovered that.
"Interdens" is the best stuff to protect hardware as it exerts minimal pressure but expands muli-directionally a hell of a lot.
We use the pink substance for lining 60 minutes vision panels, although other systems have a white liner.
Generally (assuming it's not marked) a salty tasting white seal will be palusol based. A black one intercalated graphite. any others will be either mono ammonium phosphate or amonium polyphosphate.
Be careful of the less expensive products as they do not perform as well (surprise surprise).
Hi again RB.
Fraid I've never had intercalated graphite and chips before. Can you equate your strange tastes to something I may have eaten at one time, whilst sober?
-
Nearlythere,
I can't account for the behaviour which proceeded the discovery that these things taste different! A bit off the subject but do you know how to tell the difference between white and red oak? An equally bizarre answer awaits
-
Nearlythere,
I can't account for the behaviour which proceeded the discovery that these things taste different! A bit off the subject but do you know how to tell the difference between white and red oak? An equally bizarre answer awaits
Thinking.
-
Hey Redbadge I heard a rumour that your wife is a fireeater and thats the only way you can kiss her after a show?. Someone else mentioned dragon but we wont go there.
-
Hey Redbadge I heard a rumour that your wife is a fireeater and thats the only way you can kiss her after a show?. Someone else mentioned dragon but we wont go there.
It was me that started the dragon rumour!