Hinges on Fire Doors

[Tom Sutton]

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.

[Davo]

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

[nearlythere]

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.

[kurnal]

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.

[Tom Sutton]

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).

[kurnal]

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.

[Davo]

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

[Tom Sutton]

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.

[redbadge]

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.

[nearlythere]

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?

[Tom Sutton]

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.

[redbadge]

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]

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.

[redbadge]

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!

[Tom Sutton]

My second and third paragraphs are direct quote from BS EN 1935:2002.