Mitigating Dead End Corridors
For years, architect clients have asked me for solutions to mitigate a dead end corridor condition. As a quick reference, dead ends are limited to 20 feet, except in Groups B, E, F, I-1, M, R-1, R-2, R-4, S and U with a full NFPA 13 sprinkler system, where the limit is increased to 50 feet (2015 IBC 1020.4).
Up until recently, my normal suggestion has been to place a cross-corridor door to break up the length of any one corridor segment to less than 50 (or 20) feet. This has been accepted in numerous jurisdictions and also validated by an ICC staff opinion that I requested on the topic. In many cases, I have seen the cross corridor door on magnetic hold opens, to release upon activation of the fire alarm system
But on a recent project, a local AHJ has taken the stance that a cross corridor door does not mitigate a dead end condition. I scheduled a meeting with the AHJ to explain how this has been done on other projects and to share the ICC interpretation, but they were reluctant to budge. After some negotiations, the AHJ allowed the door, but insisted that it not be held open and also required a large "Not an Exit" sign on the door itself.
I have drawn up a similar situation in the image below. The corridor is serving a Group A occupancy, so the dead end limit is 20 feet. The added door is shown in red.
Dead End Corridors: What Do You Think?
Do cross-corridor doors mitigate the 20 foot dead end limit? Do you think they should be permitted to be held open?
Let me know your thoughts in the comment box!
4/16/2020 09:45:54 am
Sounds like a valid approach. I think the "Not an Exit" sign is a must have on this type of a door as the whole purpose is to prevent the rest of the normally dead end corridor as being attempted to be used for egress. Whether the door is held open or not doesn't seem to be a huge issue to me, except that I would think that a door which is not magnetically held open is probably more likely to be propped open by other means, this negating the door.
4/16/2020 09:58:50 am
Thanks for the reply, Matt. I like the point about the door being more likely to be propped open if the magnetic hold opens are not provided...will have to bring that up next time I chat with this particular AHJ!
4/16/2020 06:14:46 pm
I have seen this situation approved with a locking hardware set on the cross-corridor door in addition to the door holder and signage. Some other things to consider:
4/17/2020 07:57:56 am
5/9/2020 11:49:44 am
2) You can require all doors on magnetic holds to close upon alarm regardless of alarm initiation point. It's all in the wiring and programming, but that could mitigate concerns regarding doors being held open when no smoke is in that corridor.
4/16/2020 09:57:25 pm
4/17/2020 07:59:13 am
Thanks for sharing your thoughts Bruce!
4/27/2020 11:54:07 pm
If an AHJ is hesitant to approve a cross-corridor door to prevent continued travel in the opposite direction of an exit, I would be curious to hear their thoughts on interruption gates within exit stairs.
5/9/2020 11:57:09 am
I think in a lot of ways, dead ends are bad design. Bad for egress and life safety, but also bad for circulation under normal circumstances. My first line of defense is trying to get the architects to improve their design and eliminate long dead ends altogether. Normally a long dead end is an opportunity for another through-way for circulation or an opportunity to add some closets.
5/18/2020 11:30:05 am
Thanks for the thoughts Kelly, hope all is well with you!
10/18/2021 07:31:25 am
10/19/2021 08:53:39 am
2/1/2022 01:35:46 pm
"This has been accepted in numerous jurisdictions and also validated by an ICC staff opinion that I requested on the topic."
4/7/2022 02:03:51 pm
Is the consensus here that a cross-corridor wall and door would be treated like any other corridor wall/ door from a fire-rating standpoint?
4/7/2022 03:33:42 pm
I'm not aware of anything that would require a higher rating.
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