double leaf door gap

[ahmedh]

Hi all,

this is probably a silly question but i am going to ask it anyway. Where you have a double leaf door set, what is the permissible gap between the cold smoke seals on each door? I understand that the gap around a door should be no more than 3mm+/-1mm to allow the intumescent seal to expand (although there is more leeway with the bottom of it)

To my mind there should be no gap, if i can see through the other side then smoke can get through. The reason i ask is that we have double doors where this is the case.

thanks

[kurnal]

There should be no gap between the smoke seals. Otherwise they will not do their job. You are right that you should not be able to see through the gap.

The ASDMA do a super guide to fire doors available for free download - here:

http://www.asdma.com/bpg.html

[ahmedh]

thanks for the prompt reply. That's a nice bit of bedtime reading.

[Phoenix]

Where the doors meet you would only expect to see a cold smoke seal on one of the door leaves, the other having only the intumescent strip.  If the cold smoke seals are on both door leaves they tend to catch and rip each other out.  The single cold smoke seal should fully seal any small gap.

Stu

[nearlythere]

Where the doors meet you would only expect to see a cold smoke seal on one of the door leaves, the other having only the intumescent strip.  If the cold smoke seals are on both door leaves they tend to catch and rip each other out.  The single cold smoke seal should fully seal any small gap.

Stu

Anyone advise as to the maximum gap that can be effectively smoke sealed with double doors?
Can you, for example, get a seal which would be suitable for a gap of asound 3-4 or even 5mm with the intumesence still being capable of working effectively?

[ahmedh]

Where the doors meet you would only expect to see a cold smoke seal on one of the door leaves, the other having only the intumescent strip.  If the cold smoke seals are on both door leaves they tend to catch and rip each other out.  The single cold smoke seal should fully seal any small gap.

Stu

expect would be the operative word Unfortunately seen a few of these.

Although in an ideal situation, there shouldn't be a visible gap there often is of a couple of mm, whether that is down to poor installation or wear from the compression nature of the seals. When there is a couple of mm gaps does this then mean refitting of a brush seal?

I wonder how much smoke would pass through bearing in mind a properly fitted FD30s lets through an average of 7.5m3 per 1/2 hr and a fire door without lets through 100.

[Tom Sutton]

admedh

Point of information, Auntie LIn's guide suggests "To put all this into context, the permitted air/smoke leakage through a typical single leaf FD30S door is 15m3/hour whilst without smoke seals the same door would leak 200m3/hour". (ASDMA FD Guide paragraph 15.2) This is double your figures?

Shirley if there is a visible gap then its not doing its job and needs replacing or the gap reducing.

[ahmedh]

admedh

Point of information, Auntie LIn's guide suggests "To put all this into context, the permitted air/smoke leakage through a typical single leaf FD30S door is 15m3/hour whilst without smoke seals the same door would leak 200m3/hour". (ASDMA FD Guide paragraph 15.2) This is double your figures?

Shirley if there is a visible gap then its not doing its job and needs replacing or the gap reducing.

I agree, just playing devil's advocate i guess. So any gap is too big (and don't call me Shirley

7.5m3 per 1/2 hr is the same as 15m3/hour or am i missing something. 2 half hours=1 hour?

[Tom Sutton]

Oops! I blame it on my age.

[Auntie LIn]

"To my mind there should be no gap, if i can see through the other side then smoke can get through. The reason i ask is that we have double doors where this is the case."

ahmedh - stick with this!   You're right to say if you can see through the meeting gap then you haven't got smoke sealing.   Things have moved forward quite well since the halcyon days when I was involved in such things, but I believe companies like Lorient and Sealmaster have done a lot of work, and they should be able to provide you with good advice.   

Don't get hooked up on having the smoke seal in one edge and intumescent only in the opposite one.   There are all manner of ways of achieving sealing at the meeting edges, from one combined seal in one edge, through fire seal in one edge with a smoke seal in the other, to a mix of fire and smoke seals in each edge, but making sure the fire seals don't sit opposite each other.

[ahmedh]

thanks Auntie Lin. I will those up.

[nearlythere]

Anyone have knowledge of a product or system to seal a gap of around 6mm on single swing double doors? Thinking about putting 1mm spacer behind hinges to close to 4mm ish and then use Sealmaster system.

[kurnal]

If I recall correctly Sealmaster and envirograf do seals for up to 12mm. But the gap needs to be consistent and even.

[Auntie LIn]

Nearly - you're right to be wary of a 6mm gap, and Kurnal - anyone who sells a seal specifically to fill a gap of up to 12mm really should know better.
In a fire door test, any door with a gap greater than 6mm will fail the fire test before it's even started, because one of the failure criteria is that a 6mm gap gauge passes through the full thickness of the construction and over a designated length - which offhand I can't remember.