What's the deal with revolving doors?

January 7, 2007 10:56 AM

What exactly is the point of a revolving door? Besides getting in and out of buildings. What do they offer that normal doors don't?

Also, am I the only person who finds these things just a bit unnerving?

posted by GalaxieFiveHundred to grab bag (39 comments total)

It's all about air conditioning. Revolving doors let out much less conditioned air. And no, you're not alone - my wife will avoid them as much as she can, taking any fixed door if available.
posted by true at 10:58 AM on January 7, 2007

They are efficient from a climate-control point of view, and when two-way traffic is high, they are much higher throughput than regular doors, with crowders and bowers and scrapers and ladies-firsters. In addition, they save on doormen.

Still, Midtown Manhattan is the only place I've ever seen enough foot traffic to make this evident.
posted by ikkyu2 at 11:00 AM on January 7, 2007

Your last question is a rant and not really a question. Also a quick Google of "purpose revolving doors" got me this Straight Dope article.
posted by vacapinta at 11:00 AM on January 7, 2007

B.C. place stadium in (of all places) B.C. has revolving doors because it's a pressurized, soft-top dome, and revolving doors allow the inside of the building to remain pressurized. At least, this is what I was told when I was younger, and I've never actually questioned the validity of it. It makes sense though, given that just this past week part of the roof tore off in a windstorm and the entire roof deflated.

I don't know if this is a necessity in other buildings (perhaps it keeps heating/air-conditioning costs down?), or if it just keeps people moving more quickly.
posted by The God Complex at 11:03 AM on January 7, 2007

No drafts. In places with lots of bad weather outside, they keep the snow, wind and rain from coming inside every time someone goes in or out. Notice how you rarely see these doors in San Diego or Hawaii.

They're no more unnerving than escalators or moving sidewalks once you get used to them. You probably just didn't encounter them nearly as often when you were a kid though.
posted by dness2 at 11:03 AM on January 7, 2007

In very large buildings, sometimes the pressure differential between inside and outside can make a conventional door very difficult to open.
posted by autojack at 11:07 AM on January 7, 2007

The God Complex: I used to work in a pressurized dome, equipped with a revolving door for normal use and emergency crash doors per fire code. The couple times I disconnected the alarms and used the crash doors I found them damn hard to close against pressure, and if you opened them from the outside they were likely to smack you in the face.

One night a windstorm yanked one off. The building colapsed in short order.
posted by vonliebig at 11:12 AM on January 7, 2007

I seem to remember the stack effect having something to do with it. Autojack's point is related I think? Something about conventional doors being prone to slamming (shattering?) because of pressure differences. I'M SORRY I AM NOT MORE HELPFUL.
posted by wemayfreeze at 11:12 AM on January 7, 2007

This probably isn't why buildings utilize revolving doors, but another benefit is that you don't have to touch anything (therefore cutting down on passing around germs, etc.).

Also, I'm the opposite. I find revolving doors kind of fun. (No I'm not a kid, though I'm only 20; and yes, I didn't grow up around them.)
posted by mittenedsex at 11:14 AM on January 7, 2007

I love revolving doors and use them at every opportunity. Like escalators, they are something I thought was really cool when I was a kid, and my appreciation for them has not diminished.

Yes, it's basically all about climate control. For similar reason, you often see two sets of non-revolving doors at the opening of a store or office building in more extreme climates. Saw this at basically every store in Detroit, but rarely see it here in Seattle. Revolving doors are basically decorative here as well, although they are probably efficient enough to save money in some months.
posted by kindall at 11:14 AM on January 7, 2007

vonliebig: I thought as much, but thought I'd qualify my answer since it wasn't based on strenuous scientific or first-hand knowledge.
posted by The God Complex at 11:16 AM on January 7, 2007

Also, I'm the opposite. I find revolving doors kind of fun. (No I'm not a kid, though I'm only 20; and yes, I didn't grow up around them.)

Same. I always associate them with "special" occasions from childhood, like those walkways in airports (you know, those on-the-floor escalator things).

But I, too, am a youngin', metafilterianly speaking, so what do I know?! ;)
posted by The God Complex at 11:18 AM on January 7, 2007

you know, those on-the-floor escalator things

Slidewalks
posted by Lokheed at 11:21 AM on January 7, 2007 [1 favorite has favorites]

I love revolving doors - wish there were more of them - would have them in my house if it was practical!
posted by davidmsc at 11:39 AM on January 7, 2007

Like above has mentioned, you don't get drafts with a revolving door. There is never a direct path between the inside and the outside, so there is no way you can get any draft.
posted by defcom1 at 11:40 AM on January 7, 2007

It's simple: Revolving doors have built-in airlocks.
posted by cmiller at 11:44 AM on January 7, 2007

The big problem with them is handicapped access. Like escalators they assume a person has legs which work well.

They're too dangerous for someone using a walker, or someone on crutches, or someone who's blind, and outright impossible for someone in a wheelchair. So there will always be a more normal door.
posted by Steven C. Den Beste at 11:52 AM on January 7, 2007

Also, am I the only person who finds these things just a bit unnerving?

Yeah, I hate them, too. Especially here in NYC where others always seem to want to go through them faster then I do.

Another use for the revolving doors - you'll see this in a lot of NYC subway stations - a floor-to-ceiling revolving door leading from the subway platform to the rest of the station. This has nothing to do with climate control or pressurization, but has everything to do with preventing people from jumping over a turnstile at an unmanned subway entrance.
posted by Afroblanco at 12:09 PM on January 7, 2007

In places with lots of bad weather outside, they keep the snow, wind and rain from coming inside every time someone goes in or out.

This is exactlly it, nearly every building in Downtown Chicago has revolving doors/
posted by Steve_at_Linnwood at 12:46 PM on January 7, 2007

They are also useful in buildings with a security desk in the entrance lobby. The hospital building I work in prefers we use the revolving door to keep us in single-file so that the security desk can see each person flash their ID card, and can easily pull aside people who don't have one.
posted by twoporedomain at 12:56 PM on January 7, 2007

I've seen revolving doors in places like Schiphol that mitigate the issue of handicapped access by having a very wide radius -- perhaps three metres -- and a slow revolving speed that's motion sensitive. In places like that, I suspect the reason is more crowd control (and security) than climate control, ensuring that there's not a crush for the escalators or lifts.
posted by holgate at 1:20 PM on January 7, 2007

Revolving airlocks are common in SF. The way they usually work is to have a circular room with one door. You go in from the spaceship, the room spins a 180, and you go out through the hull. The most recent example I can think of offhand is Varley's Red Thunder.
posted by ROU_Xenophobe at 2:16 PM on January 7, 2007

It's already been stated, in a way, but here's the explanation I got. I work out with the building director of the Sears Tower, and I once asked him about the revolving doors in the building (they are notoriously hard to push) and he explained to me that if we didn't have the revolving doors, the building would become unstable the next time the elevators went all the way to the top. I am no physicist but my understanding of his explanation (which literally involved a formula that I no longer recall) had something to do with air displacement. The whooshing mentioned in the Straight Dope article gets to it somewhat. There are actually airlocks in the building's loading docks, and for handicapped access to the building, two separate doors are involved (one opens to let the handicapped individual into an anteroom, and then that one closes behind the person; then the other door opens to let the handicapped person on their way).

One of the coolest photos I've ever seen is a picture he took of a sunset from the antenna at the top of the Sears Tower (not the Skydeck - the literal top of the tower - outside).
posted by MeetMegan at 2:46 PM on January 7, 2007

Also, am I the only person who finds these things just a bit unnerving?

I got my arm stuck in one once in a hotel in Oslo.
posted by Brittanie at 3:12 PM on January 7, 2007

Living in New York, I love love love revolving doors because I have seen what happens when there is brisk two-way traffic and no revolving door: stack ups so severe I want to hurt people--slow people. With a revolving door and a fair amount of traffic, there is a certain equilibrium pace established and a wonderful dance of exiting and entering plays out. I recommend you come visit my office building in the morning and wonder at people working together so well.

(Also SCDB, nearly every building I've seen has regular doors, often with wheelchair buttons for those who cannot avail themselves of this wonderous contraption.)

Especially here in NYC where others always seem to want to go through them faster then I do.

Walk faster! I swear, there is nothing worse than being caught behind the slow guy.
posted by dame at 3:17 PM on January 7, 2007

Also, am I the only person who finds these things just a bit unnerving?

No, about 100 million Japanese are with you.
posted by A dead Quaker at 3:36 PM on January 7, 2007

In very large buildings, sometimes the pressure differential between inside and outside can make a conventional door very difficult to open.

In places with lots of bad weather outside, they keep the snow, wind and rain from coming inside every time someone goes in or out.

These are two of the biggest reasons -- I used to work in the Empire State Building and asked some of the facilities guys and they mentioned both of these points explicitly. The ESB was designed more as an office building than as a tourist attraction, so high-throughput of foot traffic is important, but the conventional hinged doors could be damn near impossible to open, and would result in a huge whoosh of air (along with whatever precipitation was present) when you did get them open, while the revolving doors just, well, worked.
posted by anildash at 3:56 PM on January 7, 2007

A lot of interesting answers to what I'll admit is probably a dumb question. But, I'm not very bright. So thanks for humoring me hive mind!
posted by GalaxieFiveHundred at 4:36 PM on January 7, 2007

I too like the fact that you don't have to touch anything. And, in connection to what dame said, I like the fact that they keep people moving. I actually enjoy entering a revolving door behind someone slow and then pushing them through the rotation faster than they're comfortable with. Their little yelps as they jump ahead to avoid getting smacked by a huge pane of glass are funny to me. And they can't really accuse me of doing anything except pushing through the door at my own pace.
posted by bingo at 4:48 PM on January 7, 2007 [1 favorite has favorites]

According to Modern Marvels (TV show on the history channel), the Sears tower needed revolving doors to prevent the draft discussed by previous posters - with conventional doors there would be a constant, serious draft.
posted by selfmedicating at 6:53 PM on January 7, 2007

ROUX, a similar sort of "light lock" is common on darkrooms. I used to see one in my orthodontist's office, where I assume they went to develop xrays or something.
posted by hattifattener at 11:39 PM on January 7, 2007

Just one thing that I don't think has been mentioned yet: in addition to revolving doors maintaining a basically even "equilibirum pace" that keeps people from slowing down, they also keep people from going fast. This is normally not a bad thing, but it's one of the reasons why you alway see regular doors nearby. You can't evacuate a building through revolving doors, they would create a bad choke-point and probably lead to hands/arms/etc getting caught; normal exits still have to exist with the standard push-out crashbars, in case everybody decides to get up and go in a hurry.

hattifattener: when I was in highschool, we used to have one of those light locks on the darkroom. (I suppose I'm dating myself here; I suspect highschool darkrooms have gone the way of the dodo.) I always thought it was neat. For those who have no idea what we're talking about, it's a sort of single-person revolving door. Basically it's a cylinder with a doorway cut in one face. You turn it so the opening is towards you, step in, then turn it so the opening is on the other side of the wall. Thus you can enter and exit a darkroom without ever allowing light in. It requires a lot less space than a walk-thru "light trap" (matte black hallway with 2 90-deg bends). It's different from a conventional revolving door because you stand in the pivot point and the door moves around you.
posted by Kadin2048 at 3:05 AM on January 8, 2007

Now that the OP's question is resolved, what's the ruling on revolving door etiquette? My sense is it's most polite to go first, so that the other person doesn't have to push the door (they can step in after and just walk). But when there's a stream of people, the door's already moving for me. So in that case do I let the other person go first?
posted by stupidsexyFlanders at 6:31 AM on January 8, 2007

I say it's most polite if you just go when it's your time and don't interfere with the stream. Misplaced chivalry leads to clogs.
posted by bink at 7:28 AM on January 8, 2007

bink is right. Also, learn to get into the same slice someone else is leaving--don't let it go by because you weren't ready.
posted by dame at 8:46 AM on January 8, 2007

Revolving doors operate primarly as pressure locks.
posted by econous at 10:33 AM on January 8, 2007

Regarding the etiquette point raised by stupidsexyflanders, I can comment on "let the lady go first" etiquette as it is (or was at one time) applied to revolving doors.

It's not obvious, but the idea was that the man would go first, pushing the door, and the lady would follow, but the man would not exit on the other side. Instead he would walk all the way around once, eventually exiting after the lady, even though she entered after he did.

That way she didn't have to push the door, and she got to go through first.

Regards
posted by lockedroomguy at 11:28 AM on January 8, 2007

Walk faster! I swear, there is nothing worse than being caught behind the slow guy.

I'm actually a very fast walker. I just don't like revolving doors.
posted by Afroblanco at 10:14 PM on January 8, 2007

I do not like them at all. Back when I was a kid, we went to the LA Zoo, and the exits were revolving hollow pipes of death that only turned one-way. Lucky for me, I put my head in and got stuck. Fire Department had to come and get me out. Not fun at all.

At some airports, revolving doors are mandatory, and if you go through them a little too much, alarms go off and underpaid immagrant security officers magically appear. Just try controlling a five year old and several pieces of luggage at the same time.

Escalators are something to be avoided as well. I was in the mall a few years ago, and I saw the up escalator get jammed and the top 'stair' was ejected forcefully from the 'chain' and went careening down the 'stairs', followed by one or two others. Luckily, there was nobody riding them at the time, otherwise, they would have been seriously injured in the face and upper torso.
posted by Monkey0nCrack at 2:35 PM on January 18, 2007 [1 favorite has favorites]