simont | See the doors about to swing both ways

See the doors about to swing both ways

When you have an opaque door with a push plate on one side and a pull handle on the other side, I'm always a little nervous when I approach from the pull side: if I'm just reaching out for the handle and someone pushes the door vigorously from the other side, it could hurt my hand, and I rely on my hands a lot. It's likely that my paranoia about this is unnecessarily strong; if so it's due to an incident when I was about thirteen and a kid at school kicked a door incredibly hard from the push side so that it swung through 90 degrees and then shattered the doorstop; nobody's hands were near the pull side at the time, but it always stuck in my mind that they could have been, and that whenever you approach an opaque door there might be a kick-happy rugby player on the other side of it.

Clearly the correct strategy given such a door is always to push it gently if you're on the push side, so that whoever's approaching the pull side has plenty of time to get out of the way, and if you're on the other side to keep your arm loose so that it will just be pushed aside rather than hit painfully if the door suddenly opens. I do both these things conscientiously, but I can't help wondering if there ought to be a better solution involving modifying the door itself to avoid this race condition entirely.

In most cases, the simplest answer is just to put a small window in the door, but that doesn't work when it's the door to (say) a toilet and half the point is that it doesn't have a window in. There must be other options, though. Perhaps if you made the door swing in both directions and put a pull handle on each side, so that simultaneous bilateral access would result in a harmless tug-of-war rather than a painful clobbering? But some people would probably push the door regardless, and I can't think of a cunning mechanism which allows a door to be pulled from both sides but pushed from neither. Alternatively, you could have the door slide open, so that you had to push sideways on the handle, and then simultaneous operation would merely cause it to open twice as fast; but that would require structural cleverness in the wall around the door, and might well turn out to be unacceptably fiddly to implement. I wonder what other simple solutions exist.

Flat | Top-Level Comments Only

What you need is a rate-limiter on the speed of the door, like some kind of governor (http://en.wikipedia.org/wiki/Governor_%28device%29). Then the door can't be pushed open too hard.

Very firm damping on an automatic closing mechanism will do that for you.

Or non-linear damping, so the door is only hard to open if you shove it violently.

Or paint the door with percussion-sensitive explosive ;-)

I had a chemistry teacher who told a story about, when he was at school, getting hold of some of that for a practical joke on a teacher who liked to slam doors loudly. He put percussion-sensitive explosive around the doorframe before the teacher came in, with the intention that the door would slam, latch shut, and go BANG very loudly and startle the teacher. Instead, it went off before the door latched, so it sprang open again violently and knocked the teacher flying. Oops.

I think chemistry labs might have been better-stocked and less well guarded in his day...

Oh, there are plenty of stories of fun with NI₃ out there, even from my generation. Apparently it makes wonderful purple smoke.

when it's the door to (say) a toilet and half the point is that it doesn't have a window in

Frosted glass? Enough visibility to make out shapes, but not enough to see the stuff that's supposed to be hidden.

You could have an "Engaged/vacant" display[1].

[1] NB: one that works. It's REALLY ANNOYING when they don't.

The nearest gents' to my desk has two cubicles with engaged/vacant displays. One of them displays a little white blob for vacant and a red one for engaged (as you'd probably have guessed given that choice of colours). The other one is precisely the opposite way round, apparently because the door handle mechanism was put on back to front and nobody can be bothered to fix it...

Teaching everybody to be polite.

I think that if somebody pushes the door very hard, you reflexively jump backwards and don't get your hand mashed.

You can have a windowed door on toilets if there is a chicane immediately beyond it.

(S)

How about having doors which require a handle to be pushed down to unlatch them, rather than free-swinging. That way you'd get some warning from the handle that someone was coming the other way.

But people with crutches or with some kind of coordination difficulty would be entirely unable to use the door, which would be a problem if it was a toilet.

Ooh, I just had an idea. Somebody ought to build an art exhibit where to get in, the doors are all incredibly thin or with complicated handles that you need more hands than you've got to open and unacceptably high up, and there are massive giant steps up to another level - and then there are sane ways of getting into it, but you have to walk all the way around the entire exhibit to get to the first door, then all the way around to get to the second one, then to get to the sane staircase you have to walk all the way round again...and then in the middle there are models of all these incredibly tall thin people with several arms, and a little button with a picture of a normal person and "press for assistance" on it.

The Tate Modern has a room for people like you...

I always thought the room for people like me in the Tate Modern was the toilets :) they're shiny and black.

In the lab in Oxford, there was a door that had a window in it so you could see if anyone was coming through or not. However, the window was placed right above my head, so I couldn't see anyone on the other side, and to anyone in the room when I pushed it open it looked like a ghost was making the door open...

A handle that requires you to pull it the first bit to unlatch it, then pull it further to actually open it (enforcing that the door cannot be pushed open) doesn't sound too infeasible. But in plenty of places there is physically only room for the door to open one way.

You're only allowed to push the doors hard if you're wearing a white coat and pushing a trolley. You also have to say "20mg 10,000 Atropine, stat" or similar nonsense. And you mush push both doors, at once, as hard as you can!

I know what you mean about the fear of them flying open, though. Are there conditions where push/pull and no-window are required simultaneously? I can't think of any to hand.

And if someone gets hurt there's a doctor *right there*

Hmm. I wonder what the risk-minimizing way of opening a door is. The conventional palm-forward way might give you a broken wrist if slammed open.

Hand at chest level, palm down in a loose fist, like a karate block, then open the door by hinging from your elbow? As long as you have a foot out in front of you as well, so it impacts your toe rather than your face, that would result only in bruises to arm, elbow, toe and possibly backside rather than delicate bits of hand and wrist.

Dude. Iris doors!

Totally! :D

This assumes that you wear proper shoes with a rigid sole and some grip. Do not do this wearing sandals, deck shoes or trainers - if you wear light footwear, beware and be light on your feet.

Step up to the door, with your foot ahead of you in an oblique posture; place your foot firmly and move forward with your hand over the leading foot, edge-on as if cutting the air ahead of you. Approaching a door with your palm forward is asking for a broken wrist, even if the door is opened gently.

On touching the door, your knee should be behind the leading foot (you really don't want the door to hit your kneecap) and your arm should be bent, about two palms' width short of fully outstretched and resilient rather than rigid. If you can do this without breaking stride, your momentum will then carry you smoothly through the door; an unexpectedly heavy door gets an extra shove as your hips and your trailing leg launch into the next stride forward.

Your arm may flex a bit, but you're using it as a shock absorber rather than actively extending your shoulders and elbow to push the door: let your lower body do the work. Yes, this sounds like a lot of mental effort for a door... But I am a skinny weakling with arms like knotted string: most doors are a lot heavier than I am and some are deliberately designed as fire doors. Or barriers to keep the elderly, the disabled, weedy runts and mothers with pushchairs out of the nice clean photogenic building.

So what happens when someone on the other side pushes the door gently? You feel it as your arm starts moving in, or meets resistance, and can step back. When someone pushes the door hard, your arm pushes *you* backward, and you will naturally step away, withdrawing the forward foot as your centre of gravity moves backward.

When some violent nutcase hurls the door open at you, the heel of your hand and your half-bent arm will absorb the initial shock, but it will happen too fast for your body to move backwards. The door will then hit your shoe with a bang and stop. The moment you feel the bastard on the other side lose contact with the push plate, stride decisively forward with your whole body - no jerking, no slapping or punching forward, just move.

The moron then gets a taste of what he was only too happy to mete out to people on *your* side of the door - he will be off-balance, moving backwards, and the door will accelerate smoothly until it re-establishes contact. The harder he shoved the door, the harder it will hit and shove him. Walk through, brisk and confident, and ignore any protests: be sympathetic, but don't apologise to people who are beneath courtesy and never, ever admit to fault.

It is particularly satisfying watching people who have just kicked the door land sprawling on their backside; the phrase 'Stop kicking doors, it's rude' is especially helpful in these moments.

This description sounds as if you're talking about doors with a push plate on each side, rather than (as I was) ones with a pull handle on one side and a push plate on the other.

Door handles probably hit them harder.

Flat | Top-Level Comments Only

See the doors about to swing both ways

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Stat!

Re: Stat!

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