Hi Glynn
I can agree with what you are saying about stack pressures and
positive/negative pressures which affect doors indirectly throughout a
building. It is not only tall buildings which are affected, smaller
buildings accross the road may also be affected.
One solution we used in industrial office blocks where we had pressure
problems was to introduce sliding doors at intervals throughout the building
in place of swing doors, we located these doors at Tee junctions to give the
doors space to slide.
This was overseas and I am not sure how the British Standards would apply as
I do not have a copy at present. However, it is a potential solution to the
closer problem.
Dave Croft
access.forall@ntlworld,com

----- Original Message -----
From: "Glynn Williams" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, June 26, 2003 12:05 PM
Subject: Re: door closers


> HI Marcus,
>
> I have just opened up my P.c and caught sight of this debate, which
> is an area in which I have been previously involved in some research.
>
> The problems arises in doors which are fire-doors and are unlatched
> and rely purely on the closer spring/hydraulics to keep a fire-door
> securely closed upon it's seals.
>
> Latched doors in public buildings with lots of traffic are not really
> suitable.
>
> Smoke-sealing and fire-doors have to comply with BS.476 Pt 31.1 (and
> I believe building regulations Part B, Appendix B.1 for new doors in
> alterations, fire-precaution work etc).
>
> Particularly if you were talking about circulation doors across
> corridors
> or protecting a stair shaft, means of escape. Where smoke leakage under
> a pressure of 25 pascals should not exceed 3 cubic metres volume per
> metre
> of door-seal per hour.
>
> Ever tried putting new smoke seals onto an existing and presumed to be
> sound
> fire-door in a public building (already subject to draughts and
> differential pressures in a stair-shaft) to improve fire-safety? I'm
> sure we may have done that thinking we have done a good job.
>
> But how many having specified the work to B.S etc have then gone on to
> test
> the door over a few hours with a pressure test rig and instrumented the
> test
> and recorded leakage and sustainability of air-pressures?...at 25
> pascals and beyond?
>
> You would be amazed how leaky some 'sound' looking doors, fully sealed,
> can be. Obviously the quality of the components and installation is very
> influential. We all quote B.S's etc in our specifications, thinking we
> have got it covered, then depend upon the ability of the average
> commercial contractor, who after all is only trying to make good to some
> doors (joinery work)to somehow make it work.
>
> Next time you go shopping to an old established, multi-story type store
> with a back of store fire-escape stair and with landings marked up as
> refuges. As you walk down the stair and past the doors accessing the
> store's various floor levels, if they are shut, as an experiment just
> check the chinks of light showing through the door gaps/seals from the
> more brightly lit shop interior. Remember B.S permits a bit of leakage
> around the lock and hinges.
> But it doesn't take much of a gap at 25 pascals to leak quite a lot!.
>
> At 25 pascals and above you would be amazed even with a fairly strong
> fire door spring, how some doors can be blown open completely loosing
> their
> seal. What if this was a refuge door?
>
> Clearly aiming to meet the standards for the protection of all the
> buildings
> occupants for fire escape and then still making them accessible for
> disabled people (25 to 30N max) is quite a task on unlatched doors.
>
> Strangely BS 8300:2001 section 7.3.2 'Fire Doors Fitted with
> Self-Closing
> Doors',  discusses this very issue, but then in Note 1 talks about a
> maximum
> closing force of 30N, when what we need for access/egress is a suitable
> closer for fire with a suitable opening force. Or am I being too
> pedantic here?
>
> O.k, so like hospitals, you can have circulation doors on mag-holdbacks
> released upon activation of the alarm system. But isn't this just the
> time
> when you want to get people (including disabled people) out of the
> building
> quickly? And disabled people will have to pass through doors then
> closed?
>
> A compromise (because I am not sure that there is a perfect and
> affordable answer) might be to choose a closer that has the special
> properties of having high-strength when shut, to try and maintain the
> integrity of BS.476 31.1 etc but which upon opening reduces it's force
> needed to push open once moved off it's seals. I will leave you to check
> out your own products.
>
> As for closing, latching speed, I suspect that some door-closer models
> on the market have better latching/closing speed adjustment than others.
> The
> ones suitable for electronic security latching where you need to avoid
> bounce, so have the characteristics of a decelerating but firm close
> could be suitable. But check out, if on a fire-route door, they meet all
> the other requirements! Setting the operating pressures at zero to
> reduce stiffness may not be the total answer. Maybe this is why
> BS.8300:2001 advises caution on the subject. If in a tall building,
> subject to stack-effect and variable
> pressure conditions you may find that keeping doors regularly adjusted
> and
> optimized quite an ongoing exercise.
>
> Regards,
> Glynn
>
>
> -----Original Message-----
> From: Accessibuilt list [mailto:[log in to unmask]] On Behalf
> Of Marcus Ormerod
> Sent: 26 June 2003 08:16
> To: [log in to unmask]
> Subject: door closers
>
> Hi all
>
> Yesterday I was asked about the effect of trying to reduce the closing
> force of doors with oil-filled door closers, rather than the spring
> mechanism type. This came about since I had generally recommend reducing
> the tension on door closers to make doors lighter to open. The
> maintenance person said that the only adjustment on an oil filled door
> closer is to reduce, or enlarge the size of the aperture through which
> the oil passes. However, the net effect of enlarging the hole whilst
> making the door easier to open (less oil resistance through the
> aperture) was that it would shut quickly as well (the oil flows back
> quicker). No other adjustment being available.
>
> If this is the case then recommending adjusting the door closer is going
> create a problem as much as it solves one. Has anyone else come across
> this issue?
>
> Thanks
> marcus
>
> Marcus Ormerod
> SURFACE
> The University of Salford
> Bridgewater Building
> Salford
> M7 1NU
> Tel +44 (0)161 295 5405
> Fax +44 (0)161 295 5011
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>
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