Skyscrapers

[banth]

A friend told me that the really high skyscrapers have to use revolving doors for entrances and exits to control air flow because if there was just a door, and it was left open, the people on the top floors would be pushed over by the pressure/wind caused.

Is this true or was he pulling my leg?

Ta
x

[xrayspecs]

Partly. The reason is that a tll building acts like a chimney. updraft cause by rising warm air in tall buildings creates a positive pressure. This means that potentially anyone opening a ground floor door would be sucked in to the building as pressure equalized. Revolving doors prevent excessive pressure building up and being relesaed in one dramatic burst when a door is open.

[gary baldy]

This follows on (sort of) from a question yesterday about skyscrapers. The height of buildings was held back not because of the technology to build the actual structure but by really mundane things like water pressure, plumbing and the air pressure issue xray talks about. And of course it wasnt until Mr Otis invented the elevator that engineers could consider building very tall buildings because people were not prepared to walk up flights and flights of stairs.
Some of the problems with 'equalisation' in tall buildings have been over come but is still an issue.

[qapmoc]

Didn't you know that the famous photo of Marilyn Munroe with her skirt blown up was actually taken coming out of an office on the upper floor of a old skyscraper when somebody left the door open at ground level.

[kempie]

You should also consider that for buildings in the USA, it is conventional for external doors to open outwards. This would mean that the problem was not that you would get sucked in through the opened door, but rather that the door would be very difficult to open in the first place.

[jimmer]

i think its more to do with heating the lobby more efficiently.

jim