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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Fire Safety => Topic started by: Mushy on August 07, 2009, 10:55:05 AM
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Hi
most fire doors I have come across have 3 hinges...is this the rule or the practice?
I came across this... http://www.firesafe.org.uk/html/fsequip/firedoor.htm
but I can't find the info on the number of hinges
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Hi Frank
First of all firesafe.org is run by our old friend TW Sutton and is an excellent source of good information.
Ideally all fire doors should be purchased and installed as complete door sets or as door assemblies. In such a case the number of hinges will be determined by the manufacturer and whatever configuration was submitted for testing.
Guidance on the specification of hinges etc for fire doors is given in the Door and Hardware Federation / Guild of Architectural Ironmongers Code of practice for fire door hardware.
BS8214 - the code of practice for door assemblies does not refer to the number of hinges (or very little else of use for that matter)
In the real world it is common to find upgrades to existing buildings in which fire door leaves are fitted to existing frames. Timber fire doors are generally heavier than standard doors and need the support of three hinges, in addition the exposure to a fire on one side of the door tends to cause the door to warp towards a fire- tis said that three hinges help reduce the distortion (but how many doors have you seen with three latches?)
The best source of info on this subject is the "Best practice Guide to timber fire doors" published by the Architectural and Specialist Door manaufacturers and if you speak to Auntie Lin of this forum she will probably let you have a copy. This guidance contains a recommendation 20-8-1 that all fire door leaves (remeber this is only covering timber doors) should be hung on at least three hinges or four if the door leaf exceeds 2250mm ( but then this would surely be a specialist door set).
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Thank you for that Kurnal...its appreciated :)
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Mushy
If you had gone to the section "Fire Door Furniture and Ironmongery" there is a link to Fire Door Fittings and Ironmongery
(http://www.firesafe.org.uk/html/fsequip/fd_irnmon.htm) click on Fire Door Fittings and Ironmongery (http://www.firesafe.org.uk/html/fsequip/fd_irnmon.htm#hod) and and finally there is a link to pfd document "Guide to interpreting Markings for Single Axis Hinges" (http://www.firesafe.org.uk/assets/docs/guid1935.pdf) which should tell you all you need to know.
In that document you will find,
"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."
If you do not seek you shall not find.
However all this applies to certified fire doors and as I suspect the vast majority of fire doors do not fall into this category then Kurnal’s advice is stop on.
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I am not savvy enough with the history of doors prior to the BS476 regime for testing of them to be sure of this, but I would imagine that the third hinge used to be more of a 'requirement' (Just like the 25mm rebate) to stop the door bending when subjected to fire, and they used to be fitted half way down the door as this is where they will perform that duty more efficiently. The more recent (Post BS476) ones tend to have the third hinge fitted close to the uppermost hinge, which is indicated in the pdf TW linked to be more of a physical support to counteract the bending force of the self closer.
That is an interesting document TW. Just something else to be aware of. :)
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Absolutely Civvy our mentors told us we needed three hinges and we never questioned them. However when I was treading the boards, we nearly always required doors to be upgraded and when you plant a three eighths sheet of asbestalux on a door then the third hinges was needed. I just seems, although necessary, things are just getting more complicated by the hour. :(
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All this three hinges bit is because that is how the door was tested. Testing doors is expensive and for the sake of a £2.00 hinge why not go for the belt, braces and a piece of rope.
Fire doors can be heavier than non FR doors but maybe not that much heavier to require a third hinge. Someone probably just said lets just stick on another hinge to be sure, to be sure, to be sure. If the door passes it then becomes the normal level of fire door hardware.
Who would now want to spend thousands to have a fire door tested with two hinges. For the sake of maybe saving a couple of quid there is no point really.