Talk:Revolving door

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[edit] Revolving Doors

What advantages do revolving doors have over normal ones?

There is a full explaination of energy savings and sustainablity and stack pressure on MIT's Sustainablity Website:
         http://sustainability.mit.edu/Revolving_Door

 The article mentions that they can installed to minimize heat loss.  However, I would think a normal door would do a better job of that.  Also, it claims security is one factor, but many revolving doors are permanently unlocked.  What other theories or facts do you have about them? Superm401 | Talk 22:06, July 13, 2005 (UTC)

The number of people is usually in the thousands that use revolving doors, in large lobbys, skyscrapers, storefronts with glass, malls : with lots of traffic.

Well, IMO, revolving doors increase the efficiency and flow of human traffic. One (normal) revolving door can have four people at once, and serves both entering and exiting traffic. Meanwhile, hinge doors usually only serve one direction. Thus, it is more efficient to have revolving doors rather than hinge doors. Hope this helps! Flcelloguy | A note? | Desk 22:10, 13 July 2005 (UTC)

I suppose that's right. I guess I've seen too many situations when there wasn't a large flow of traffic and revolving doors actually slowed people significantly. I can understand how much time could be saved in a high-flow environment, though. Superm401 | Talk 22:37, July 13, 2005 (UTC)

"With revolving doors, the directions of traffic are well defined and while a given individual may take longer to get in or out, the overall throughput is probably higher." Anonymous comment by 68.179.157.56 Samw 03:14, 26 October 2007 (UTC)

I think the genesis of revolving doors was high-rise buildings, which my memory tells me are or were associated with differential air pressures at different heights, which can lead to a tendency to draw air in or expel it at ground level ... a revolving door does not care about such things; whereas hinged doors can be held closed or blown open by air pressures ... indeed, for whatever reason, I thought revolving doors were an enabling technology. But I could be wrong. Memory eh? Who'd trust it? Meanwhile the diverse answers you might get for this question bring to mind Call My Bluff. But I see that airlock has a passing mention of revolving doors. And a little googling brings up this article which talks about differential air pressures but in the context of keeping cold air out. More generally, they seem to be a good thing for keeping a controlled environment isolated from the outsider world.

Check engineering "STACK PRESSURE"

Try this google query for some more.  --Tagishsimon (talk)

The air pressure comment seems to be a valid possibility. However, cold air can be brought in through revolving doors fine, so that part seems incorrect. Anyway, both are insufficient because revolving doors are used in many one floor buildings as well. Superm401 | Talk 22:37, July 13, 2005 (UTC)

Revolving doors also save money by keeping in air conditioned air in the summer, and reducing heat loss during winter. --HappyCamper 22:27, 13 July 2005 (UTC)

I simply don't see how this is true. There is still air flow. Superm401 | Talk 22:37, July 13, 2005 (UTC)

An exterior revolving door setup has walls around 2 opposing quarters of its perimeter [1]. If you are passing through the system, the "door" in front of you will leave contact with the wall of the system as the "door" behind you makes contact. There is never a complete path for air to flow between inside to outside. Only the parcels of air actually inside the door will be exchanged. -- Cyrius|✎ 22:56, 13 July 2005 (UTC)

I already knew that. As you said, the air in the chambers is exchanged. I think that is about the air that would be exchanged because of the opening of a normal door. Do you disagree? Superm401 | Talk 23:26, July 13, 2005 (UTC)

When you open a normal door the difference in air pressure can cause a wind to flow in and up the lift shafts. I've hears that it can be so bad that it's difficult to close the door. Theresa Knott (a tenth stroke) 00:01, 14 July 2005 (UTC)

And a normal door in a high traffic building would be open almoste all the time. EnSamulili 12:21, 14 July 2005 (UTC)

In summary: yes, each trip through a revolving door may exchange one "parcel" of air, but a steady breeze through an open, conventional door could exchange much more air than that. Thus the efficiency claim. Steve Summit 22:13, 15 July 2005 (UTC)

Also, with respect to the air pressure claim: there's a reasonably well-known story at MIT that when the 20-story Green Building (building 54) first opened, an unexpected wind-tunnel Bernoulli effect at the base of the building meant that the (conventional) doors couldn't be opened if there was ay significant wind blowing, and people had to enter and exit via the basement tunnels to adjacent buildigs, until revolving doors could be retrofitted. Steve Summit 22:21, 15 July 2005 (UTC)

Security: The hinges aren't right there to play with as with normal doors. If you manage to get through a normal door, you're home free - with a revolving door you may still have another "door" to go through. ¦ Reisio 23:11, 2005 July 13 (UTC)

As I said, many are permanently unlocked. Superm401 |

(usually with attendents in the lobby) Talk 23:26, July 13, 2005 (UTC)

There's more security even when they're unlocked - it takes longer to get through them to the other side. ¦ Reisio 23:40, 2005 July 13 (UTC)

But even if that is security, why would a company want that? Superm401 | Talk 23:46, July 13, 2005 (UTC)

Sorry, but are you really asking why a company would want security? ¦ Reisio 02:07, 2005 July 14 (UTC)

NO. I am really asking why a company would want "security" that only entails slowing down customers entering to transact while the business is open. Superm401 | Talk 03:38, July 14, 2005 (UTC)

Simple - it doesn't slow them from entering. It takes longer to get from outside to inside, not to actually cross the area. When you open a normal door, you are immediately accessing a new area. When you're using a revolving door, you are not. As for actually going from point A to point C with door B somewhere in the middle, a revolving door probably decreases total travel time. ¦ Reisio 12:36, 2005 July 14 (UTC)

Why would the company want it to "take longer to get from outside to inside" while they are open? Superm401 | Talk 12:51, July 14, 2005 (UTC)

You're missing the point. It's not that it takes longer to get inside, it's that the (number of seconds) transition from being outside to being inside is longer. The only situation in which this might actually hamper efficiency would be if all business inside were done within a few feet of the doors...and even then it'd probably still be more efficient to use revolving doors. ¦ Reisio 15:02, 2005 July 14 (UTC)

I agree with Flcelloguy. The problem with standard doors is that when foot traffic increases, you have a situation where people get in each others' way and are constantly trying to push past each other. With revolving doors, the directions of traffic are well defined and while a given individual may take longer to get in or out, the overall throughput is probably higher --CVaneg 23:20, 13 July 2005 (UTC)

When a hinged door is open there is a direct path for wind to enter at high speed, and wind can blow a hinged door open or hold it shut. In high traffic places even two sets of swing doors don't help because often both sets will be open at once. Revolving doors provide no path for wind because at least one doorseal is in contact with the "jamb" at all times, and because they have equal areas all around their point of revolution, no amount of differential pressure will cause or prevent rotation. Sure a finite amount of air is exchanged with each person that passes but this is minor; with no wind behind it, most of the air probably keeps rotating with the door. For security, I believe the chief advantage is the difficulty of rapid egress of fleeing felons; a regular door can be held open by an accomplice, but a revolving door is a much less appealing getaway channel. The mention of no exposed hinges (and perhaps a more easily secured locking mechanism) also rings true. The bit about two-way traffic I think is less clear; larger revolving doors take as much lateral space as two normal doors (which could be allocated to "in" and "out" directions) and with smaller revolving doors it's hard to enter the same chamber that someone is leaving, so with constant traffic in one direction the backchannel goes unused. Sharkford 15:24, July 14, 2005 (UTC)

In answer to several questions about security, in day and age, with a regular door someone can walk up to an open door, throw a bomb inside and run. That's a lot more difficult with a revolving door. DJ Clayworth 17:01, 14 July 2005 (UTC)

I added a history section, quoting from the original patent the advantages cited by the author. Samw 02:29, 15 July 2005 (UTC)

Also, revolving doors are used in air-supported domed stadiums, like the Pontiac Silverdome (which I've personally been to several times). When 80,000 people try to leave at once, the revolving doors keep the air pressure relatively moderated while still providing significant traffic movement. If they had 'standard' doors, the sheer number of people living in a small time span (15 minutes or so) would deflate the roof in hardly any time. PolarisSLBM 18:35, 21 November 2006 (UTC)

[edit] Needs better diagram

I think the graphic being used could be improved in a number of areas:

• It needs to be shown in an isometric projection, straight on and top-down views fail to convey how they work,
• Pushbars should be added,
• The partially curved walls need to be shown as well,
• Bonus points if someone can show an animated version

--Hooperbloob 05:26, 3 February 2006 (UTC)

Gimme a few days and I can toodle about in AutoCAD, see what I can come up with, huh? PolarisSLBM 18:32, 21 November 2006 (UTC)

[edit] Image on revolving doors in Turkey

This image is listed as a door from Turkey revolving clockwise. I believe Turkey is a right-hand drive country. Shouldn't it have a counter-clockwise revolving door? Samw (talk) 00:04, 29 May 2008 (UTC)