Wait a minute – WHAT???
For several months I’ve been trying to find out more about the research that was conducted years ago regarding the use of a mullion on a pair of doors. It could be one of those urban legends of door hardware, but as the story goes, when a university tested egress through a pair of doors, people could exit faster through a pair with a center mullion. I’ve tried to track this down through at least 30 different hardware people with a special interest in codes and I still haven’t been able to find it. If you have any insight into this research, click here and scroll down to leave a comment. If your tip leads to the successful apprehension of this research, you’ll receive a reward from the IR Prize Vault.
Today, an article hit my desk regarding recent research at the University of Tokyo. The study showed that placing an obstruction next to a door helped people exit more efficiently by preventing them from jostling for position at the door and creating friction. The research also showed that people exiting in a single-file line were the most efficient. Perhaps the mullion in the earlier test helped people form two lines to allow for faster egress.
It always shocks and saddens me to read about tragic fires and find out that many of the victims were trapped right at or in the door opening, only steps from safety. Hopefully this type of research will further improve the safety of our exits in the future.
Here is an article about this research from Inside Science, and another one from Homeland Security Newswire. This article from Physics Central Buzz Blog includes comments from readers.
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so THAT’S why many places leave the mullion in place on exit doors or doors exiting from a large area (auditorium or sports place)instead of using vertical rod exit device.
maybe also the theory of mullion in place helps faster exit is to remind people to be more aware of others during an emergency and to exit as you said single file instead of a big clump to block the flow and people get hurt. with a mullion it provides a physical divider in the opening so its 2 people at a time pass through instead of 4 or 5 and cause the big pile of people causing a “traffic jam” in the doorway.
I have always thought as well that no mullion=faster exit, but yea, this now makes alot of sense to provide a more organized egress and more awareness for others.
speaking of exit devices, those on this pair of doors appear to be Chip’s siblings in photo, (Falcons)
Be sure to thank your elementary school teachers for a fine job they did when you had to line up in single-file line for recess.
I was also taught that more people could exit thru a pair of doors with a mullion. The reason I was given is that with a mullion the door act as 2 single doors that would both open to 90 degree’s where a pair without a mullion the people funnel into the middle and both leaves only open to 75 degree.
I would REALLY like to find out where that is stated, or a study that supports it. I’ve been looking for it for years!