Saving yourself from death by jumping in a plunging elevator.


Just an FYI. Your reply was right on the money. It may interest you that Bill Nye the Science Guy did an experiment that illustrated exactly what you stated in your answer. At the time, he was on a cable access show called ‘Almost Live’ out of Seattle. The experiment involved a scale model elevator, an egg, and a springboard to make the egg ‘jump’ just before the elevator hit the bottom of the shaft. The result, broken egg.

Hi and welcome to the SDMB! I love Bill Nye the Science Guy. It helps if you include a link to the column in question.

Something that all knowing Cecil should have mentioned.

In modern elevators there is no such thing as plunging.

If the wire snaps, a safety mechanism will shoot out and stop the elevator. It’s the pressure from the wire that prevents the safety mechanism from going off during normal use. Send your thanks to Elisha G. Otis.

ie. the answer doesn’t have any meaning, the situation would never happen (well, maybe, but that would be some seriously insane tough luck)

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A better chance of survival would be to flatten yourself on the floor. The force of the impact would be spread out over a wider area. Although it wouldn’t save you from a 100 mph free fall, you might survive a several story drop.

Spreading yourself out on the floor is the worst thing you could do. No matter how much you “spread out the force of impact”, you’re still going from your free-fall speed to zero. You want your acceleration to be as small as possible, which means that you want that change in velocity to take as long a time as possible. So the best you can do is to be standing upright at the beginning of impact, but to then end up flat on the floor at the end.

Ahh, but the deceleration is nearly instant, isn’t it? I have nothing scientific to back this up, but I’d bet that a person couldn’t react fast enough to make a difference, and that spreading out flat is still the best plan. Standing up just concentrates all the force at the time of impact through your ankles. I mean, you’d have to have very good timing, and be able to judge the exact moment of stoppage to even have a chance, wouldn’t you?

At least if you’re standing, your crucial soft parts (pelvis and up) will fall to a nice soft cushion on your jellied legs. Spreading out flat just means that your rib cage and skull are going to get squashed immediately upon impact instead of a split second later.

UUUGH. I think I’ll take the stairs at work tomorrow. :wink:

That’s good to hear. Although for whatever it’s worth, the answer might apply to several action movies.

I have just read this column (yes, I know, what took me so long etc) and would just like to comment on how beautifully written it is: accurate – naturally – and pithily concise. Nice one, Cyr… er, Cecil.

Just to share in reflected glory, I too have written about this. As Cecil said, it won’t work. And on some elevators, it really won’t work.

There’s a world of difference between “nearly instant” and “completely instant”. A completely instant stop would mean infinite acceleration, if only for a moment. Needless to say, that’s bad. A nearly instant stop, by contrast, would give you a high, but still finite, acceleration. You want to make that acceleration as small as possible, which means that you want to make the time as long as possible (even if it’s still not very long). Last time this came up, I estimacalculated that a person landing with an optimal hit-roll-flat maneuver could survive a fall from a thousand times as high as someone landing already flat. Which, I think you’ll agree, is not a negligible difference, even if we add allowance for less than perfect conditions.

I’m pretty sure that the show Worst Case Scenario had a segment on how to survive in a plummeting elevator. Unfortunately it isn’t mentioned on their website. IIRC, it involved keeping your back against the wall and having your legs infront with your knees bent (kind of like sitting on an invisible chair). I don’t remember what the rationale was for that position being better than any other.

How do u get that it’s the worst thing to do? in worst case scenario servival handbook it’s EXPERTS say to do exactly that, lie on your stomach and cover your head, fetal position’s OK to

Experts on what, surviving free-falling elevators? That can’t be a very popular career choice. :rolleyes:

Can I be a survival expert? I’ve managed to do it for over 21 years, that’s gotta be worth something. :wink:

Um, I can hardly read your post due to the lack of punctuation, but it seems like he said that was the BEST thing to do.

Just for the heck of it, the elevators with the greatest potential for a catastrophic downward fall are older hydraulic elevators installed prior to about 1973.

As mentioned above, traction (roped) elevators are equipped with a multitude of brakes, governors and sensors for safety. These elevators run in tall buildings at speeds of 500 to 2000(!) feet per minute, depending on the installation, typically around 750 fpm +.

Hydraulics are in smaller buildings, run at lower speeds of 75 - 225 fpm and are (in most states) equiped with no brakes, governors or safeties.

The logic is that if a catastrophic break occurs in the oil line or piston the oil can only exit the system at the max rate of the size of the oil line (usually about 4" dia). This would allow the elevator to descend at a speed substantially faster than “contract” speed, but not so fast as to cause more than minor injuries when it hits the buffer spring located at the bottom of the guide rails.

However, older hydros possess an Achilles heel in the form of “single bottom jacks”. The hydraulic cylinder in mid to tall hydraulic elevators hangs in a hole below the bottom of the elevator shaft. In the old days these holes were not sealed, the jack (hydraulic piston) itself was not sealed and had a single layer bottom.

After years of environmental and electrically induced corrosion in a dank hole the single bottom can corrode, and then fail and allow the hydraulic oil to rush out at a rapid pace which causes the elevator to reach dangerous downward speeds.

Serious catastrophic injuries, including deaths have resulted because of these accidents.

Modern elevators use a double bottomed jack, a cased hole and a piston sealed in PVC to prevent environmental leakage, so this is no longer a concern.

Most single bottom jacks have been replaced and modernized, but cost and difficulty is considerable, so some building owners continue to operate them as they are.

Reputable elevator companies will not provide service contracts to these buildings. Unfortunately, in my state it is impossible for the State Elevator Inspector to shut them down because they met code at the time of installation.

So if you find yourself in a building that was built around the late sixties, riding in a creaky old hydraulic elevator, you’ll have a little something to contemplate as you go past the fifth floor…