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Fotheringay-Phipps
01-19-2016, 12:22 PM
I'm thinking the best idea would be to lie down on the floor. Since the force of the impact will be directly down, it will press your body into the floor, but there wouldn't be much if any external trauma, since the floor would shield your body from the impact. The only problem is that your internal organs will be violently thrown about inside your body. Doesn't sound pleasant, but I'm thinking it might be preferable than having your body slam into the floor.

As to what position, I could see it to ways. My first thought is to lie on your side with one arm under your head, thus giving your brain some cushion. But I'm wondering if the internal organs issue might be worse if you're on your side (since people are wider than their thickness).

But of course, this is idle speculation and not based on any sort of knowledge or expertise. I'm wondering what more informed opinion holds.

Czarcasm
01-19-2016, 12:40 PM
How many floors free-fall are we talking about here?

running coach
01-19-2016, 12:41 PM
Bend over, kiss your ass goodbye.

Lying down won't work. Your entire body will still experience the sudden stop at the bottom.

Si Amigo
01-19-2016, 12:41 PM
Get on all fours and let your arms and legs act as shock absorbers between the trunk of your body and the floor, allowing a better chance for your internal organs and head to remain less injured.

Inner Stickler
01-19-2016, 12:43 PM
I would assume you'd want to lie as flat as possible with your arms over your head to distribute the force of the impact as widely as possible and provide your fragile head with some protection and padding from anything falling on top of you.

Chihuahua
01-19-2016, 12:43 PM
I once read that falls from dangerous heights are most survivable for people who land on their feet rather than land in a horizontal position. The thinking is that the energy transfers into your legs first, and so even if you suffer terrible fractures it still absorbs some energy before it transfers to your pelvis, spine, and (eventually) head.

You wouldn't want to be laying prone on the floor of the elevator any more than you would want to fall out of a tree and land in a belly flop position. I'm not sure what the difference is between falling onto an immobile floor and having a moving floor abruptly stop. The mechanism of injury appears to be identical.

Czarcasm
01-19-2016, 12:45 PM
If there is someone else inside the elevator with you, lie on top of them.

cochrane
01-19-2016, 12:48 PM
I once read that falls from dangerous heights are most survivable for people who land on their feet rather than land in a horizontal position. The thinking is that the energy transfers into your legs first, and so even if you suffer terrible fractures it still absorbs some energy before it transfers to your pelvis, spine, and (eventually) head.

You wouldn't want to be laying prone on the floor of the elevator any more than you would want to fall out of a tree and land in a belly flop position. I'm not sure what the difference is between falling onto an immobile floor and having a moving floor abruptly stop. The mechanism of injury appears to be identical.

If you're in an elevator free-falling at a conservative speed of 60 mph, I think that if you're standing, the shock of the impact is likely to knock you off your feet, anyway.

Chihuahua
01-19-2016, 12:51 PM
nm

CalMeacham
01-19-2016, 12:56 PM
People always talk about elevators falling, as if this is some common occurrence. It's like the way they're worried about teleporters scrambling their body parts with those of a fly.


Moving boxes that transport people and material up and down have been around for hundreds of years. They'[re depicted in Pieter Brueghe the Elder's paitning of The Tower of Babylon (1563), and are probably a great deal older.

Elisha Otis didn't inventor the Elevator (he actually purchased an elevator company, Evans Lifts, from Britain) -- he invented a safety stop that would prevent the elevator from falling if the chain/rope snapped.

https://en.wikipedia.org/wiki/Elisha_Otis

At the New York Crystal Palace, Elisha Otis amazed a crowd when he ordered the only rope holding the platform on which he was standing cut.[1] The rope was severed by an axeman, and the platform fell only a few inches before coming to a halt. After the World's Fair, Otis received continuous orders, doubling each year

All elevators have arresting devices to prevent accidents. Despite what you might see in films likeThe Matrix, cutting the cables on an elevator won't precipitate people to their deaths.

enalzi
01-19-2016, 01:10 PM
The other problem not mentioned is that the elevator not going to stay intact with any significant fall. Even if you survive hitting the ground, you not have the entire top of the elevator crashing down on top of you.

DrCube
01-19-2016, 01:12 PM
If you're in an elevator free-falling at a conservative speed of 60 mph, I think that if you're standing, the shock of the impact is likely to knock you off your feet, anyway.

Absolutely. That's also part of the shock-absorbing effect of standing up when you land. Paratroopers learn to land in ways that minimize injuries and they start with their feet. I wasn't a paratrooper, but Drilll Sergeants always called our ass the "fourth point of contact", and I'm assuming points 1-3 were feet, ankles and knees.

sitchensis
01-19-2016, 01:14 PM
How do you lay on the floor when you're weightless?

cochrane
01-19-2016, 01:17 PM
People always talk about elevators falling, as if this is some common occurrence. It's like the way they're worried about teleporters scrambling their body parts with those of a fly.


Moving boxes that transport people and material up and down have been around for hundreds of years. They'[re depicted in Pieter Brueghe the Elder's paitning of The Tower of Babylon (1563), and are probably a great deal older.

Elisha Otis didn't inventor the Elevator (he actually purchased an elevator company, Evans Lifts, from Britain) -- he invented a safety stop that would prevent the elevator from falling if the chain/rope snapped.

https://en.wikipedia.org/wiki/Elisha_Otis



All elevators have arresting devices to prevent accidents. Despite what you might see in films likeThe Matrix, cutting the cables on an elevator won't precipitate people to their deaths.

Absolutely. When the Mythbusters tested the elevator free fall, they disabled all of the safety stops before they cut the cable.

DrCube
01-19-2016, 01:23 PM
How do you lay on the floor when you're weightless?

You don't. You're going to be in free fall just as if you were jumping from the upper floors down an empty elevator shaft. The only difference an elevator will make is that the ceiling will crash down on top of you after you land.

And possibly (?) there are some shock absorbers or something that might make landing on the elevator floor slightly better than landing on the concrete floor of the elevator shaft. I don't know, I haven't been in the bottom of an empty elevator shaft. Possibly there will be some friction on the way down that will prevent the elevator from being in complete free fall, so you might still have some weight holding you to the floor.

TriPolar
01-19-2016, 01:37 PM
And possibly (?) there are some shock absorbers or something that might make landing on the elevator floor slightly better than landing on the concrete floor of the elevator shaft.

I saw the bottom of an elevator shaft that had some huge coil springs at the bottom. I imagined after slamming into the floor of the elevator car I'd be suddenly hurled upward to crash into the ceiling.

There are pneumatic elevators that have a very limited rate of descent, on top of the already mentioned safety devices that will stop a falling elevator car. The much greater danger is stepping into an elevator car that isn't there, or one that stops when it's not aligned with the floor. Even an inch of misalignment can cause people to trip and fall, and it's an indication that the elevator is malfunctioning and may move again with the doors open.

Peter Morris
01-19-2016, 02:07 PM
People always talk about elevators falling, as if this is some common occurrence.
...
All elevators have arresting devices to prevent accidents. Despite what you might see in films likeThe Matrix, cutting the cables on an elevator won't precipitate people to their deaths.

This.

Depending on design, an elevator car may have several cables suspending it from above.

If all of them are severed, the car has a counterweight that will stop it falling too fast.

If the counterweight is also severed, the car will have some sort of braking mechanism that will grip onto the shaft and stop it falling.

If all else fails, the car and/ or the shaft will have buffers (big springs) at the bottom to soften the impact.

If you are ever in a falling elevator, just keep calm, you're gonna walk away from it.

iamthewalrus(:3=
01-19-2016, 02:09 PM
I saw the bottom of an elevator shaft that had some huge coil springs at the bottom. I imagined after slamming into the floor of the elevator car I'd be suddenly hurled upward to crash into the ceiling.I don't think the physics on that work out. The whole car might bounce, but what's going to accelerate you faster than the rest of the car to bounce into the ceiling?

Whiskey Dickens
01-19-2016, 02:11 PM
If there is someone else inside the elevator with you, lie on top of them.

One last romp, hey? Sure hope it's Jennie from HR and not Marvin from Accounting I'm in there with.

Tom Tildrum
01-19-2016, 02:17 PM
Your best bet is probably to do like Kirk with the Kobayashi Maru. Add some extra cables before you get on.

kayaker
01-19-2016, 02:18 PM
Take the stairs.

Chronos
01-19-2016, 02:38 PM
You want to distribute the impact over as much of your body as you can. Therefore, lying down flat is the absolute worst possible thing you can do. Start off vertical, and you can distribute the impact over the entire length of your body. Start off horizontal, and you're distributing it over perhaps an inch or two.

TriPolar
01-19-2016, 02:41 PM
I don't think the physics on that work out. The whole car might bounce, but what's going to accelerate you faster than the rest of the car to bounce into the ceiling?

Beats me, that's just what I imagined when I saw it. I guess the end result if the car actually jumps in the air is that I end up splattered on the floor a second time when it comes back down.

Si Amigo
01-19-2016, 03:03 PM
You want to distribute the impact over as much of your body as you can. Therefore, lying down flat is the absolute worst possible thing you can do. Start off vertical, and you can distribute the impact over the entire length of your body. Start off horizontal, and you're distributing it over perhaps an inch or two.

Wouldn't standing up concentrate the impact over a much smaller footprint?

Chronos
01-19-2016, 03:12 PM
Footprint doesn't matter. What matters is how far you travel while decelerating.

ftg
01-19-2016, 03:12 PM
Re: Elevator falls don't happen.

From my family: An uncle was in an elevator with another guy at an industrial site. Something went wrong and the elevator fell. My uncle spent weeks convalescing. The other guy didn't make it. IIRC something on the order of 4-5 floors.

From US history: There's a rather famous elevator fall from the B-25 vs. The Empire State Building crash (https://en.wikipedia.org/wiki/B-25_Empire_State_Building_crash).

Just because a safety mechanism exists, doesn't mean it works 100% of the time.

Anyway ... the reason why lying on the floor with your arms under your head sounds good to me is because the elevator floor is unlikely to undergo quite as fast a deceleration as your body would hitting the floor a second after it came to a stop.

In general you want to be tight against the thing that's going to take the longest to slow down.

Peter Morris
01-19-2016, 03:27 PM
Re: Elevator falls don't happen.

Who said they don't happen?

The point is, on the rare occasions they happen, the safety mechanisms reduce the damage.

From my family: An uncle was in an elevator with another guy at an industrial site. Something went wrong and the elevator fell. My uncle spent weeks convalescing. The other guy didn't make it. IIRC something on the order of 4-5 floors.

Interesting. Details?

From US history: There's a rather famous elevator fall from the B-25 vs. The Empire State Building crash (https://en.wikipedia.org/wiki/B-25_Empire_State_Building_crash).

Just because a safety mechanism exists, doesn't mean it works 100% of the time.

It worked well enough that the person in the car survived the fall.

Ignotus
01-19-2016, 03:59 PM
Would it make sense to stand leaning with your shoulders against the wall and your feet some distance away from it? That way, you would make some use of friction to neutralize the impact.
(Though, if you have the time to prepare for it, you're probably screwed anyhow.)

Tom Tildrum
01-19-2016, 04:03 PM
Footprint doesn't matter. What matters is how far you travel while decelerating.

Or to put it another way, you want the rest of your body to be the crumple zone for your brain.

Dr. Strangelove
01-19-2016, 04:06 PM
You want to distribute the impact over as much of your body as you can. Therefore, lying down flat is the absolute worst possible thing you can do. Start off vertical, and you can distribute the impact over the entire length of your body. Start off horizontal, and you're distributing it over perhaps an inch or two.

That assumes infinite deceleration. If the elevator came to a stop instantly, you're probably right that you'd want as much extra length as possible to decrease the required deceleration.

In practice, though, the elevator won't come to a stop instantly. Most elevators have a spring or hydraulic buffer at the bottom. In this case, you aren't gaining as much from having an extra body length.

Having force spread out over your back is by far the best way to avoid injury in high-G situations, as Colonel John Stapp found out in the fifties. If I knew the elevator would peak at 50 gees over 3 meters, I would definitely pick the flat on back position. If the distance were much less, standing might be optimal.

Czarcasm
01-19-2016, 04:11 PM
everything you wanted to know about elevator injuries and deaths* (http://www.elcosh.org/document/1232/d000397/Deaths+and+Injuries+Involving+Elevators+and+Escalators+-+A+Report+of+the+Center+To+Protect+Workers'+Rights.html?show_text=1)

*but were afraid to ask

Ignotus
01-19-2016, 04:14 PM
Or to put it another way, you want the rest of your body to be the crumple zone for your brain.

I'm not sure I want my brain to outlive the rest of my body -- even by minutes!

TriPolar
01-19-2016, 04:16 PM
I'm not sure I want my brain to outlive the rest of my body -- even by minutes!

I know what you mean. I considered responding to the OP by saying "Stand on your head".

Mangetout
01-19-2016, 04:25 PM
How do you lay on the floor when you're weightless?

You can't. The trouble with any of the answers in this thread is also: you have a very short time to react. Let's say you're free-falling from the top floor level of the Gherkin (https://en.wikipedia.org/wiki/30_St_Mary_Axe) - you have about 6 seconds to get yourself into whatever position you think is the best one - and you're attempting it in freefall.
From what I have seen of amateur first-time freefall experiences in parabolic flights, there's generally a lot of flailing about (and in that context, the participants know it's coming). It's really unlikely that you'll get the hang of it, and achieve your (probably fruitless) objective in the few seconds available.

Tom Tildrum
01-19-2016, 04:35 PM
I'm not sure I want my brain to outlive the rest of my body -- even by minutes!

I do, but then I think about who's deciding that for me.

iljitsch
01-19-2016, 04:38 PM
If you lie on the floor the upside is that there's no impact from your body hitting the floor, but it also means the deceleration is pretty much instantaneous. Not sure whether the net result would be better or worse.

I can provide somewhat of a data point regarding falling from several meters on your feet. That happened to me when I was 17 and I had climbed a statue and was coming back down. I lost my grip and fell and hit the ground some 3 - 4 meters lower. This was marble or something similar and my feet were bare.

When I got to the hospital (under my own power!) it turned out I had broken my heel bone in one foot. The doctor was surprised that I hadn't broken my back, too, as that typically happens when people break their heel bone. I guess I was lucky because when I fell, my knees were bent so the force wasn't transmitted directly from my feet to my back through the bones, but rather, absorbed by my feet and leg muscles. I'm guessing that from a larger height you'd still hit your head pretty hard.

Machine Elf
01-19-2016, 04:43 PM
Re: Elevator falls don't happen.

Maybe not, but sometimes they go up really fast. (https://www.youtube.com/watch?v=WrvsfP1PxYk) :eek: (news article) (http://www.telegraph.co.uk/news/worldnews/southamerica/chile/10886847/Chile-lift-slams-man-into-roof-after-rocketing-31-floors-in-15-seconds.html)

Czarcasm
01-19-2016, 04:47 PM
Maybe not, but sometimes they go up really fast. (https://www.youtube.com/watch?v=WrvsfP1PxYk) :eek: (news article) (http://www.telegraph.co.uk/news/worldnews/southamerica/chile/10886847/Chile-lift-slams-man-into-roof-after-rocketing-31-floors-in-15-seconds.html)Wonkavator!

Sage Rat
01-19-2016, 04:58 PM
The way that circus performers and free runners accomplish falls from greater heights is that they fall feet first and roll when they hit the ground, trying to convert the vertical motion into horizontal. Of course, generally, they already have some horizontal momentum and generally they're not going to be falling from all that high (unless it's onto a pad) so the time to react at the bottom of the fall is greater. They'll also know where the bottom is, so they can time their movements accordingly.

You're probably screwed, but if the elevator is falling from a low enough height. I'd venture to guess that it's still your best bet.

Doug K.
01-19-2016, 06:47 PM
It's like the way they're worried about teleporters scrambling their body parts with those of a fly.

It may be safe in TV and movies, but in real life there has never once been a teleportation that didn't end up with the person mixed up with a fly.

BrotherCadfael
01-19-2016, 06:55 PM
Absolutely. When the Mythbusters tested the elevator free fall, they disabled all of the safety stops before they cut the cable.They showed the uncontrolled descent in real time (vs. slow motion). One of the most terrifying things I have ever seen! So I have to concur with running coach: Bend over, and kiss your ass goodbye.

WF Tomba
01-19-2016, 08:10 PM
If there were something on the ceiling that you could grab and hang onto with your arms and legs, you might have a chance. The elevator itself becomes your shock absorber.

ftg
01-20-2016, 04:06 PM
If there were something on the ceiling that you could grab and hang onto with your arms and legs, you might have a chance. The elevator itself becomes your shock absorber.

You don't have the strength and your body doesn't have the resilience for this to make much difference. Like those movie stunts with one person holding onto another when there's only one parachute. The holdee is dead meat. May as well just let go at the start and the holder will suffer fewer arm injuries.

The idea of pressing your back against a wall is interesting. You're still going to collapse quite fast but it might reduce the odd injury or so.

CalMeacham
01-20-2016, 04:35 PM
It may be safe in TV and movies, but in real life there has never once been a teleportation that didn't end up with the person mixed up with a fly.

As I've said before -- if I ever build a teleporter, my first public demonstration will be teleporting myself and a fly at the same time.



And people in movies don't always end up mixed up with a fly. One guy in Son of the Fly got mixed up with a guinea pig.

Leo Bloom
01-20-2016, 06:32 PM
You want to distribute the impact over as much of your body as you can. Therefore, lying down flat is the absolute worst possible thing you can do. Start off vertical, and you can distribute the impact over the entire length of your body. Start off horizontal, and you're distributing it over perhaps an inch or two.
Or horizontal over another:
One last romp, hey? Sure hope it's Jennie from HR and not Marvin from Accounting I'm in there with.
As Jason Bourne demonstrates (https://www.youtube.com/watch?v=XhpJ11dNp2o).

Fubaya
01-20-2016, 07:03 PM
Absolutely. That's also part of the shock-absorbing effect of standing up when you land. Paratroopers learn to land in ways that minimize injuries and they start with their feet. I wasn't a paratrooper, but Drilll Sergeants always called our ass the "fourth point of contact", and I'm assuming points 1-3 were feet, ankles and knees.

I think this, the parachute landing fall (http://www.defence.gov.au/health/infocentre/journals/ADFHJ_oct06/images/73-2.jpg), is the best bet. (or however close you can get to that while in free fall). Hundreds of thousands of people in the military have spent decades using it and no one has come up with anything better so far.

It uses as much of the body's non-vital parts that it can to absorb as much shock as possible. I don't know how you could improve it.

dracoi
01-20-2016, 09:01 PM
How do you lay on the floor when you're weightless?

I know the OP specifies freefall, but in reality, it's impossible for it to be perfect freefall. At the very least, the elevator shaft is full of air. The elevator is also going to touch the edges of the shaft at least a little bit; that's how the braking mechanisms work and the contact will still be there even if the mechanisms aren't stopping you.

So the result might be greatly reduced apparent gravity, but it should be enough to make maneuvering possible.

Philster
01-21-2016, 11:47 AM
Take the stairs.

Terribly dangerous! Stairs are a leading cause of injury and death.

Nars Glinley
01-21-2016, 12:17 PM
Absolutely. When the Mythbusters tested the elevator free fall, they disabled all of the safety stops before they cut the cable.

And there's also the fact that many elevators use hydraulics instead of cables. I'd guess that they're even less likely to fail catastrophically.

Snnipe 70E
01-21-2016, 05:18 PM
A cable elevator free falls up not down, the counter weight free down. The only way a cable elevator can free fall down is the cables (normally 4 to 8) all fail at the same time and the cables on the emergency break also fail.
If you are in a cable elevator and it starts to free fall your best bet is to get on the floor and try to protect your hear. When the car hits the end of the shaft it is going to stop NOW. You will continue to move and fly up and hit the top of the passenger area of the car. The number of floors the car moves up, the weight of people in the car, the weight of the car, and the weight of the counter weight will determine the speed when the car comes to a sudden stop.

Now a hydraulic elevator can fall down. Until around 2000 most hydraulic elevators did not have any free fall safety break.

Snnipe 70E
01-21-2016, 05:24 PM
And there's also the fact that many elevators use hydraulics instead of cables. I'd guess that they're even less likely to fail catastrophically.

With multiple cables the chances of a catastrophe failure is slim.
With a hydraulic the piping from the valve to the jack can fail at any fitting.
If it is an old style jack it is possible to have a failure where the end of the jack has the cap is welded.

iljitsch
01-21-2016, 05:40 PM
Hydraulic elevators are considered so safe they don't need additional brakes. Regular elevators usually have safety features that make sure they won't fall even when all the cables break.

Chronos
01-21-2016, 05:44 PM
If you're still connected to the counterweight, you're not free-falling. And the counterweight is designed to be approximately equal to the average weight of the elevator car when it's in use, and so whether the car would be pulled upward or downward in such a situation depends on whether it's loaded more or less than average.

Snnipe 70E
01-22-2016, 09:12 AM
Hydraulic elevators are considered so safe they don't need additional brakes. Regular elevators usually have safety features that make sure they won't fall even when all the cables break.

But they are not safer because of the lack of safeties. For a cable elevator to free fall would take several systems failing at the same time. A hydraulic elevator can free fall one of several parts fail.

iljitsch
01-22-2016, 10:04 AM
A big steel pipe filled with oil doesn't really have too many failure modes. If it springs a leak somewhere, the oil will rush out and the elevator will drop, but considering the speed of oil rushing, that's a far cry from anything that can possibly be considered free fall.

ruadh
03-02-2017, 02:35 AM
‘There was a bang and we were gone’ (http://www.irishexaminer.com/ireland/there-was-a-bang-and-we-were-gone-444087.html)

Forget it. From now on, I'm taking the stairs.

bardos
03-02-2017, 10:56 AM
The most insane thing about this thread is why someone did not post the famous "Need answer fast?"meme

SamuelA
03-02-2017, 07:52 PM
This topic jogged my memory. One of the book accounts of the world trade center disaster talked about elevators plunging into the basement, killing the passengers onboard. Apparently this happened (http://usatoday30.usatoday.com/news/sept11/2002-09-04-elevator-usat_x.htm) - those safety brakes are not perfect.

A number of other people were killed because the elevators have a mechanism that locks the doors and they will remain locked if power is lost. This is less than ideal - it should be possible for someone trapped in an elevator to escape.

Chronos
03-02-2017, 08:44 PM
Well of course the WTC elevators plunged into the basement. The whole building plunged into the basement. What would you expect, an elevator car remaining suspended on a single cable sticking straight up into empty air?

SamuelA
03-02-2017, 08:58 PM
Well of course the WTC elevators plunged into the basement. The whole building plunged into the basement. What would you expect, an elevator car remaining suspended on a single cable sticking straight up into empty air?

If you skimmed the linked article, it refers to two of the express elevators plunging and killing 40 people from the deceleration at the bottom. This was long before the building collapsed - the cables were cut by the aircraft impacts, and the safety brakes failed to work properly. 4 people survived.

Velocity
03-02-2017, 09:04 PM
I once read that falls from dangerous heights are most survivable for people who land on their feet rather than land in a horizontal position. The thinking is that the energy transfers into your legs first, and so even if you suffer terrible fractures it still absorbs some energy before it transfers to your pelvis, spine, and (eventually) head.

I think there's a big difference though, which is that an elevator has a ceiling. If you are in a standing position, and your elevator free-falls to an impact, you're going to smash flying headfirst upwards into the ceiling. Depending on what the ceiling is made of, you might snap your neck.


Whereas, out in the open - say, if you jumped off a 3-story building and landed feet-first - then you would in theory suffer broken legs, etc., but your head wouldn't smash into anything.

TimeWinder
03-02-2017, 09:12 PM
If you are in a standing position, and your elevator free-falls to an impact, you're going to smash flying headfirst upwards into the ceiling.

Uh, no? The ceiling might come down to meet you, but you're not going to fly off the floor to meet it.

HoneyBadgerDC
03-03-2017, 04:12 PM
There mayb be some cussioning effect of the shaft becomming slightly pressurised

TimeWinder
03-03-2017, 08:50 PM
it's also worth pointing out that industrial elevators (particularly those used in construction sites and other semi-temporary locations) have a fairly sketchy safety record, as do elevators in parts of the world less concerned about building codes and the like.

Standard commercial passenger elevators, as installed as permanent fixtures in modern buildings are extremely safe: As noted by the instances in this thread (which may be all or nearly all of them), fatalities and severe falling elevator-caused injuries happen only in extraordinary conditions, at least in the United States and similarly regulatory nations.

Chronos
03-03-2017, 10:37 PM
The elevator will be slightly cushioned by air resistance, while you within the elevator will be affected almost not at all by air resistance. This means that the only interior surface of the elevator you will be hitting will be the floor.

Leo Bloom
03-04-2017, 12:37 PM
This topic jogged my memory. One of the book accounts of the world trade center disaster talked about elevators plunging into the basement, killing the passengers onboard. Apparently this happened (http://usatoday30.usatoday.com/news/sept11/2002-09-04-elevator-usat_x.htm) - those safety brakes are not perfect.
....

Well of course the WTC elevators plunged into the basement. The whole building plunged into the basement. What would you expect, an elevator car remaining suspended on a single cable sticking straight up into empty air?
Chronos's response and the posing of this question is an exemplary case of the :smack: that happens when physical (indeed, mental/conceptual) analytical frames are off by jus theees much and it seemed you didn't even have to check.

In NO WAY am I imputing conspiracy willfulness to SamuelA, but rare events from any besetting conundrum--of thought or emotions all the way to elevator failures and sudden skyscraper collapses--will often allow the analysis to falter.

Chronos
03-04-2017, 12:46 PM
The point with the WTC is that there's obviously some catastrophic set of conditions that will cause all of the elevator systems to fail, and that threshold must obviously be at some point short of what happened at the WTC, so there was no question that the elevators were going to fail. It was just a question of at what point in the general failure of the building it would happen.

Weisshund
03-04-2017, 01:44 PM
Assuming OP situation is

Cabled Elevator
All cables snap
No functioning brakes or safety devices
No way to check speed until the car hits bottom.

Lay on your back on the floor
and Pray

Easier to pray laying down.

I'm not quite sure if you can even reliably remain on the floor in free fall?
You may have to be happy with kissing the ceiling?

If you just dropped 60 floors, any springs in the bottom aren't going to mean much to your body at all, they wont be long enough to decel the car slow enough.
Automobiles have springs, they don't help the occupants when the car drives off a bridge.

Like other people said, even if you survived the initial stop, doubtful you will survive the rest of the elevator stopping, because you will be under it.

If, in free fall, your body decides it want to visit the roof rather than the floor, things could be more fun as you sling shot into the floor, THEN the roof and other pieces crash in on top of you.

I am not sure about in buildings, but it has happened in mine shafts before.
Praying was the best option.
Futile perhaps, but it keeps the mind occupied better than pissing and shitting yourself while screaming incoherently.

Then again, you could get lucky, as long as no other pieces decide to kill you.
People have been blown out of B17's in mid air, with no chute, and lived.

People have gone sky diving, had their chute totally fail and hit the ground, and lived.

Me, i dont have that kind of luck.
I'd try to get all my cloths off before landing though, then someone could open a great debate thread on why the falling victim was totally naked.
Shame i wouldn't be around to read it

Lucas Jackson
03-04-2017, 09:17 PM
This.

No. Not that. The OP was a hypothetical that Cal was fighting and in no way answered. Nor did the OP suggest it was common. Suggesting hypotheticals, however improbable, is as common as dirt around here. And anecdotally, my uncle was also severely injured when a construction elevator that he was riding in fell.

SamuelA
03-04-2017, 10:11 PM
The point with the WTC is that there's obviously some catastrophic set of conditions that will cause all of the elevator systems to fail, and that threshold must obviously be at some point short of what happened at the WTC, so there was no question that the elevators were going to fail. It was just a question of at what point in the general failure of the building it would happen.

Pedantry aside, when I read the written accounts of the disaster from surviving witnesses in the lobby - describing the screeching as the elevator cars plummeted to hell in the basement - it was a pretty evocative scene. Also, I always assumed that the cars had perhaps a separate safety brake for each wheel on the side of the elevator shaft and/or independent safety mechanisms made with different mechanical designs.

This is probably not the case - there would not have been multiple failures that day, each resulting in fatalities. Realistically, there are probably deployed elevators that have just 1 safety mechanism other than the main cable.

It doesn't mean elevators are unsafe - they are probably safer than taking the stairs, that's for sure. And Paternosters...jesus. I hate to change the topic, but a Paternoster - if you try to board a paternoster, and get a limb or even your head caught between the moving car and the approaching floor or ceiling, you're going to lose the limb, correct? I don't see how the system could have safety mechanisms that allow the paternoster system to keep moving yet detect a caught body part before it crushes or severs it.

jjakucyk
03-04-2017, 10:20 PM
This episode of The Secret Life of Machines details pretty well all the safety equipment for roped elevators, as well as the inherent safety of hydraulic models: https://www.youtube.com/watch?v=iSLmzjE_woQ It also shows why escape hatches have generally been eliminated, as you're usually much safer stuck inside. What terrifies me is an elevator without a skirt below it (which I have rarely seen, but is shown in the video), such that if you were in a stuck elevator halfway between floors, got the door open, then tried to jump down to the floor, you could easily stumble backwards and fall down the open shaft below the cab.

As for air cushioning, that only really works if there's one elevator in a single shaft with tight clearances. Any building more than a few stories tall is likely to have at least two elevators, and usually they're in a single shaft open to each other specifically to minimize the piston effect on air. Fast moving elevators can push so much air around that they'd be trying to force it out through the doors, whistling, and causing all sorts of other nuisances. I guess you could have a building with a slow-moving elevator that's pretty tight in its shaft, such that under normal operation the air could sneak around the sides without much trouble, and even so a free fall from just three or four stories up can be super damaging.

I have heard of cases where falling roped elevators have gotten some extra cushioning from the wires and maybe even the broken cables themselves (pulled down by the also falling counterweight I presume) bunching up in the shaft below the cab.

Snnipe 70E
03-04-2017, 11:54 PM
Maybe not, but sometimes they go up really fast. (https://www.youtube.com/watch?v=WrvsfP1PxYk) :eek: (news article) (http://www.telegraph.co.uk/news/worldnews/southamerica/chile/10886847/Chile-lift-slams-man-into-roof-after-rocketing-31-floors-in-15-seconds.html)

I just looked at this one. It looks like a elevator that it's brake failed and the motor also failed. This can happen if you hit the emergency stop on a elevator that the brake is not working on. But I think it was just a drive motor or generator failure, aslong with a break failure.

Chronos
03-05-2017, 08:13 AM
Air cushioning would certainly be a lot more effective in a tight shaft, but you'll get some nonzero amount of it even if the elevator is falling through completely open space. Not much, but enough that the surface you inside will end up against will be the floor.

Riemann
03-05-2017, 10:00 AM
Air cushioning would certainly be a lot more effective in a tight shaft, but you'll get some nonzero amount of it even if the elevator is falling through completely open space. Not much, but enough that the surface you inside will end up against will be the floor.

Intuitively, I tend to agree. It's not just question of whether a pressure differential can build up. Terminal velocity for an elevator may be rather slow. The bottom of the elevator is an un-aerodynamic flat face that is held perpendicular to the direction of acceleration.

Snnipe 70E
03-05-2017, 06:35 PM
Air cushioning would certainly be a lot more effective in a tight shaft, but you'll get some nonzero amount of it even if the elevator is falling through completely open space. Not much, but enough that the surface you inside will end up against will be the floor.

I doubt if the pressure under an elevator gets up to more that 10" of water pressure. or less than 0.050 psi. Not much stopping force in air pressure build up.

jjakucyk
03-05-2017, 07:08 PM
^ Good point. I can see air resistance having an effect on terminal velocity, with the elevator cab being about as blunt and un-aerodynamic as you can get, but it's also very heavy too so the terminal velocity would be quite high. The Mythbusters elevator fall episode was terrifying when they showed it rocketing past the open doorways. Yes it blew around a lot of air, but it didn't seem to slow it down much. It was a 9 or 10 story building and the elevator still fell at over 50mph.