The Rotating Door

Day 245 / 365

Rotating doors are quite an interesting invention. They might feel like just a novelty thing to have but they actually serve an important purpose

There’s a myth that goes around that the guy who invented it did so as he didn’t have to hold the door open for women, or get stuck holding the door open for everyone.

Well, that isn’t the case. Rotating doors were invented as they are energy efficient. With normal doors, there will be a loss of cooling or heating inside the building whenever the door is opened. Rotating doors prevent this by acting as an airlock. In this way, they can provide up to 30% energy savings as compared to conventional doors.

In high rise buildings, hot air would rise up creating a lower pressure area at the bottom. This is known as stack pressure. With normal doors, as there is a pressure difference between the outside and inside air, air would come rushing in when the doors are opened. Rotating doors prevent this as well.

While these doors allow more people to get out at a time, they have been known to be fire hazards as well. In 1942, a building in Boston caught fire that led to about 500 deaths. One of the main reasons was that the building had a single revolving door exit and in the whole frenzy the people were not able to get out quickly enough. This is the reason why most buildings would have normal emergency exits on the sides of revolving doors.

This post is part of my 365 Day Project for 2019. Read about it here

Yesterday’s blog — Doctor’s recommending cigarettes and radioactive energy drinks