cutting the door stop to fit a maglock on FD30

[Brig]

Having googled and searched this forum to no avail I'm hoping someone here can help...

A site has FD30's fitted with 25mm door stops. I'm in the process of fitting maglocks to them and on one door I have to mount it vertically on the side (the door has a curved top), in order to stop it sticking out further than necessary I was wondering if I could cut out a 20cm section of the doorstop and fit it there?

Google only seems to mention gaps in the intumescent strips and nothing about a continuous door stop.

Any advice is appreciated.

Thanks

[Tom Sutton]

In the 1970's fire doors were tested to BS 476 part 8 and required an inch (25mm) doors stop to pass the test. Later that decade intumescent strips (IS) were introduced to improve the fire resistance and it was claimed the inch stops prevented the heat getting to the IS making it less effective. By the time BS 476 part 22 was introduced the inch rebates had been removed and the fire doors passed the new test, which was more demanding, indicating that with IS you didn't require inch rebates.

Consequently I would suggest providing the lock doesn't break the continuity of the IS the fire doors integrity will not be reduced. 

[Brig]

Thanks a lot for the reply Tom, the lock won't inhibit the IS at all.

[Neil Ashdown MAFDI]

You should be aware that, in a fire situation, heat transfer from this large amount of metal to the timber door leaf could cause premature fire separation failure. The top edge and the upper part of the closing edge is more vulnerable to fire (than the lower parts of the door leaf) and therefore it would be sensible to risk assess the effects of a premature failure for the timber based doors that are fitted with magnetic locks. 

With regard to removal of stops, it is always better to add a timber fillet to the door frame reveal instead so as to support the hardware securely. I realise this may not be very practical, but fitting such a device to the door-frame closing jamb doesn't seem very practical anyway!

You should also bear in mind that mag-locks tend to distort the timber door leaf where they pull the leaf towards to magnet. During installation, care should be taken to ensure the leaf remains in plane in its closed position.

[Tom Sutton]

I must clarify that my response assumes the fire doors are fitted with intumescent strips as well as inch door stops, if not, then I do not recommend the breaking the continuity of the inch door stops for any distances.