I’m sure that you’ve encountered this phenomenon at some point during your life. You’re walking into a building and come up to a set of double doors. You grab the handle on the left and give a tug. Instead of the door opening you just about dislocate your shoulder, at which point you notice the small sign that says “Please use other door —>”. You grab the other handle, give it a tug (but not as hard as the first tug) and continue on your way, probably cursing the owner of the door under your breath and wondering why the door isn’t allowed to open.

My most recent encounter with this was yesterday when I offered my boss a ride home. On our way into the lobby of the building I live in, I chose the door on the right (which I knew opens) and he chose the one on the left (which I knew doesn’t open). Before I could warn him, he tugged on the door, which didn’t move, and complained loudly about this.

Why do buildings with doors like this often have one of the doors set so it can’t be opened?

The commercial building next to where I live has a bunch of double doors on its various entrances and as far as I know none of the double doors open on both sides, even though there are hundreds of people who pass through them every day. At lunch time, it’s not uncommon to see people bunching up because there’s not enough capacity, which there would be if both doors opened.

Can anyone shed some light on this?