Revolving door
They are also energy efficient; they act as an airlock to prevent drafts, decreasing the loss of heating or cooling for the building as compared to a standard door.
[2] Skyscraper design requires a means of draft block, such as revolving doors, to prevent the chimney effect of the tall structure from sucking in air at high speed at the base and ejecting it through vents in the roof while the building is being heated, or sucking in air through the vents and ejecting it through the doors while being cooled, both effects due to convection.
Normally, the revolving door is always closed so that wind and drafts cannot blow into the building, to efficiently minimize heating and air conditioning loads.
Turnstile exit-only doors are also often used in subways and other rapid transit facilities to prevent people from bypassing fare payment.
They are similarly used at large sports stadiums, amusement parks, and other such venues, to allow pedestrians to exit freely, but not to enter without paying admission fees.
[6] H. Bockhacker of Berlin was granted German patent DE18349[7] on December 22, 1881 for Tür ohne Luftzug or 'Door without draft of air', which used a rotating cylinder with a door which after entering, the user then turned around to the exiting direction.
The patent describes it as having "three radiating and equidistant wings ... provided with weather-strips or equivalent means to insure [sic] a snug fit".
[9] An urban legend, dating back to perhaps 2008, claims that the invention was motivated by his phobia of opening doors for others, especially women; according to Snopes, there is no evidence to support this.
[10] In 1889, the Franklin Institute of Philadelphia awarded the John Scott Legacy Medal to Van Kannel for his contribution to society.
[11] In 1899, the world's first wooden revolving door was installed at Rector's, a restaurant on Times Square in Manhattan, located on Broadway between West 43rd and 44th Streets.
These studies focused on providing detailed measurements of the quantities of air and heat transferred inside the compartments of a door as it revolves.
[citation needed] A more recent experimental study[19][20][21] carried out at Imperial College London's Department of Civil and Environmental Engineering, provided more insight into the flow physics by which air is transferred across a revolving door.
As such these design curves still form the basis of the target leakage rates for revolving doors recommended by the ASHRAE standard 90.1 in the US.
While preferred by building owners for energy conservation, revolving doors may be avoided by some people due to the perceived greater physical effort in using them.
