This question has come up yet again…Is it true that people can exit more quickly through a pair of doors with a mullion than through a pair without a mullion? I have been hearing about this since my early days in the hardware industry, and apparently, many of you have heard it too. Dozens of people have contacted me over the years to ask where to find data corroborating this, and many mentioned that they heard it in “hardware school.” Despite my exhaustive attempts to find the original source of the information, I have not located it.
I’m not sure why it is so important to have concrete evidence of egress movement through a pair of doors, as the model codes don’t really differentiate. If I encountered an architect who didn’t want me to specify a removable mullion, I might try to use the egress theory as support for a mullion, along with the benefits of using rim panic hardware with a removable mullion – increased security, decreased maintenance. But otherwise I’m not sure what the compelling need for the data is…it’s not like adding a mullion will allow the number of exits to be reduced. Maybe everyone continues to search for it because it’s seemingly impossible to find.
I know that some of you use software for egress modeling – I even found a professor who had run this particular test before and said that it was indeed true that you can move people through an opening with a mullion more quickly. But he had not officially documented the data or saved a video of the test that was run using their software. I’d love to end this quest once and for all…is there anyone out there who has the ability (or knows someone who has the ability) to run a comparison using software and save it in a format that I could share it? Video would be ideal.
This is an interesting video about egress when there is an obstacle in front of the door, but I’m not sure what the impact would be if the “obstacle” (the mullion) was right in the door opening. I’d also be interested to see if having the doors NOT held open would have an impact.