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dr.ed
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Sep 15, 2004, 2:58 PM
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I'll post a link to a calculation estimating this soon, 60' is the rough number. The limiting acceleration that a human can withstand is determined by the mechanical strength of the Aorta. When a body is accelerated past this limit, the Aorta ruptures and death is the consequence.
Climbing had a plot sometime back on the probablilities. It was derived from records in NYC of suicides an suicide attempts from buildings. These numbers represent the results of people jumping out of buildings, so the heights are well determined. I assume that the people were in free fall, and hit a the ground but no additional information was given.
Please don't count on one of the rare stories of someone falling from some great height and living. Many of these stories fall under the catagory of "urban legend", often repeated, never documented. Falling is serious. Here is a condensed table from the graph:
height:................10'...20'...30'...40'...50'...60'...70'...80'...90'..100'..110'
% probability of
limb fracture:......41 ...63 ...70 ...76 ...80 ...82 ...85 ...88 ...90 ..93 ...94
spine fracture:......5 ...10 ...13 ...16 ...20 ...23 ...27 ...29 ...31 ..33 ...35
death:..................2 ....7 ...12 ...21 ...35 ...49 ...62 ...74 ...83 ...92 ...95
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masterjuggler41
Sep 15, 2004, 3:04 PM
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There is an article in the back of the latest Rock and Ice mag. about possible deaths from a 4-foot fall. you may want to check that out.
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thegreytradster
Sep 15, 2004, 3:35 PM
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One thing to keep in mind about Dr.Ed's chart that may skew it. The data was generated from intentional jumps. The participants probably would have a much higher likelyhood of landing on the legs or flat than an unexpected fall.
I seem to remember from some industrial safety stuff years ago a LD 50 height of somewhere closer to 12-20 ft. That was off ladders and most of those falls are unexpected, backwards and involve a head first impact. I took a quick look at OSHA's site. It's gotta be in there somewhere, but I don't have the time or patience to find it now.
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reno
Sep 15, 2004, 3:40 PM
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Depends on many different factors:
Take a 10 foot fall. Now start changing variables...
Land on a grassy hill and roll down it, dispersing energy as you go? Probably live.
Land on a grassy hill and roll down it, dispersing energy as you go, but bending your neck too far forward? Might die.
Land on flat rock? Maybe live.
Land on rock on your head? Probably die.
Land on flat grass, without holding your breath? Probably live.
Land on flat grass, holding your breath, and suffering two pneumothoraces? Might live, if you're at a city crag with an ambulance close by.
Land on flat grass, holding your breath, and suffering two pneumothoraces? Probably die if you're three days away from rescue in the Chugach.
The chart posted above is good for a "general idea" reference, but it ain't a "hard-and-fast" rule. Too many variables.
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he-man
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Sep 15, 2004, 3:44 PM
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I read somewhere once that if you take an uncontrolled fall from more than the hight of your shoulders you can die. For most of us that would be somewhere between 4 and 5 1/2 feet. I think the biggest factor is weather or not the fall is controlled. This may explain why experienced climbers have survived insane falls while Joe Noob dies on a 6ft V0- boulder problem.
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asandh
Sep 15, 2004, 3:48 PM
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:)
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feanor007
Sep 15, 2004, 4:39 PM
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as for the 22k b-24 fall, i think it's quite well documented and have also heard that a Russian fellow took a signifigantly longer one and walked away. he to landed in snow. as to how high you hve to be to die, that's like asking how deep water has to be for you to drown, and people drown in there bathtubs every year.
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robmcc
Sep 15, 2004, 4:41 PM
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In reply to: and people drown in there bathtubs every year.
Wow, it has to suck to be one of them. Can you imagine dying in your bathtub every year?
I really hope I only have to die once, and if I do, I still wanna die by misadventure.
Rob
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prufrock
Sep 15, 2004, 5:26 PM
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There are three things that decide if you live:
The amount of potential energy you have in the gravity well available to be turned into destructive force on you vital organs. IOW, fall height. This one is easy to figure out. Also, we reach terminal velocity (somewhere around 120 mph?) fairly quickly. I can't remember the usual height required, and I am too lazy to crack open my mechanics textbook and figure it out. I think it was 100 ft or less. Anything beyond the height needed for terminal velocity is pointless, as it gives no extra energy.
The second thing is the amount of time it takes you to go from fall speed to stop. The longer this time, the less force your body feels, the more likely you are to live. This is why skiers can jump off a 60' cliff with no trouble: snow is soft, and the angle of the slope and their skis allow them to avoid a complete stop altogether. 60' of air is routine for extreme skiers. Don't try it at the crag -- you'll die.
The last thing is how the force of breaking your fall is applied to your body. Or how do you land, and what parts of your body are destroyed in the process. This one is tough to account for.
So while it is simple in principle, it is impossible in practice to predict life or death in a fall. But my intuition tells me anything about 40 ft or more, and you expect a body bag.
If someone was really curious, they could count the number of people that fell from height x, divide by those that died, and thus create a rough estimate of the probability of death. Presumably with accident reports as a source (but they may not record walk-aways). I would not put much stock in the data for suicide jumpers -- they are trying to die, and almost always land on very unforgiving concrete.
In short, don't fall. If you live beyond 20 ft, consider yourself lucky.
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dr.ed
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Sep 15, 2004, 5:29 PM
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In all cases the fatality rate depends on the acceleration on impact. You have some control over this depending on how you land and what you land in. My calculation of this gives a 60' height to fall where the time to come to a stop is calculated by the bodies velocity and height. The change in the momentum divided by this time determines the force, which in turn gives you the acceleration. The fact that this number agrees with the data (50% fatality at 60') indicates that there is some element of truth to the estimate.
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mchatz13
Sep 15, 2004, 5:53 PM
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I was riding my bike at around 70mph, and some woman pulled out in front of me. The bike slammed into the side of the car and I flew over it landing some 40 feet away. Shorts, t-shirt and a helmet. Sure I had 90 staples in my arm and the back of my head, but I was out of the hospital the same day, and back in a gym two weeks later.
All about how you land and if it is your time.
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johnhemlock
Sep 15, 2004, 6:00 PM
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My friend took a 100 footer, bounced off a ledge and took another 30 footer into a gully. He was wearing a helmet and a pack, which absorbed much of the impact. One of the packstays was bent like a pretzel. Broke some ribs, punctured a lung, was playing blackjack in Vegas 10 days later. You could probably take that fall 10 times and end up dead 9 times.
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indigoboy
Sep 15, 2004, 6:11 PM
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It's not the fall that kills you it's the sudden stop at the end :angel:
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aarong
Sep 15, 2004, 6:21 PM
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I teach a fall protection course for the federal govt. -
In the occupational climbing world (antenna, tower, radar, bridge, building, etc.) stats show that 85% of people who fall from 11 feet or higher die.
While this may not apply directly to recreational climbing (i.e. bouldering) - the odds are still pretty high that if you free-fall unexpectedly and hit the ground you could die. Bouldering is a different game - in many cases you have spotters, a crash pad, and you have the expectation that you might fall so you are ready to land correctly.
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cchildre
Sep 15, 2004, 6:31 PM
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My brother took a full force header while pole vaulting onto a concrete floor from 16 feet. Broke his wrist and gave him a bunch of small brain hemmorages but no significant long term damage. I was also out caving over in New Mexico, a fellow explorer was 20 feet off the deck climbing a PVC pipe up to a ledge and snapped the pipe and fell head first to die instantly. Very tragic, I have taken longer falls and walked away with a few scratches. You can never tell. I have been in the 15% twice :)
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johnclimbrok
Sep 15, 2004, 7:01 PM
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you can die from falling while walking on the ground if you hit your head right -
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nealric
Sep 17, 2004, 10:30 PM
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I dont think it makes any sense to look at occupation hazard stats that say that 85% of falls over 11 feet are fatal.
You know there are lies, damn lies, and statistics :wink:
That is probably because there are few occupational falls in the 11-25 foot range.
You are either working on a short ladder at 0-10 feet, or way up high on a building or tower.
My personal experience (And what I have heard/red)
For Landing on Feet on a good surface/pad:
Probably no injury 0-15 feet
15-20 probably sprain/ broken limb
20-30- Almost certain broken limb/other serious injury
30-40- Life threatening injury
40-50- serious injury or death
50+ "coffin zone" as john long calls it
For landiing on side or non optimal feet landing:
0-5 feet: Probably no injury, possible cracked rib/sprain
5-10 feet: likely sprain/cracked rib/other break
10-15 feet: almost certain injury- possible very serious injury
15-20 feet: serious injury or possible death
25+ feet: probable death or paralysing injury
For landing on head:
0-3 feet: possibility of no injury/ sprained neck
3-5 feet: best case sprain, worst case broken neck
5-10 feet: proble broken neck
10+ feet: probable death
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davisjl1979
Sep 17, 2004, 10:44 PM
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A PLF in climbing shoes!! OUCH.
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thegreytradster
Sep 17, 2004, 11:47 PM
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In reply to: That is probably because there are few occupational falls in the 11-25 foot range. You are either working on a short ladder at 0-10 feet, or way up high on a building or tower
That's not true! Probably the most common fall in the construction industry is off a 8 or 12 ft step ladder or steping into a trench. These are usualy backwards, unexepected and fatal more often than the distance involved would lead one to believe!
There really isn't much relationship to the climbing world other than to emphasize th need to protect the bean!
I'm a lot more comfortable 15+ft up on rock than with the same exposure on a ladder!
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marcel
Sep 18, 2004, 1:00 AM
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I read once that 50% of industrial falls over 12' are fatal. So don't fall on the job! :D
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prufrock
Sep 20, 2004, 12:09 AM
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For the record, I mentioned up-thread that one reaches terminal velocity quickly, at less than 100'. That was from memory, and it was quite wrong.
Assuming I set the diffeq up right (and I think I did), with a terminal velocity in the area of 120 miles/an hour (195 Km/hr, 54 m/s), at around 140 feet (40 m) you are at 50% terminal velocity, and at around 800 feet (240 m), you are at 90% terminal velocity.
These are only rough, as one can change their air resistance quite easily depending upon the way they fall, and the drag coefficient stuff is only an approximation anyway (albeit a good one at low speed).
So I was way wrong. Apparently terminal velocity is only interesting for skydivers, and that energies much lower than those of terminal velocity are quite lethal.
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musicman
Sep 20, 2004, 1:09 AM
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In reply to: As a skier i'm quite comfortable with jumps of 40 to 50 fert with good landings...I used to jump 15 ft to ground no prob..(more careful with my knees these days)...from the s I've seen and jumping experience to 60+ feet I'd say 50/50 at about 40 to 50ft on ground. Lot's of variables...but with dirt and if you say did an experiment with 100 people that's my guess...
i board at Park City and they have some HUGE 60 foot jumps there (i'm still workin on the 15-20) but the thing is the landings are angled hopefully in the direction that you'll land. you are also going so fast that you aren't hitting the ground strait down. i've seen people clip the landings and hurt there feet/ankles real bad and just end up rolling the rest of the way down the landing but there is a big difference between free falling and landing on a slope going really fast.
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johnny_b_goode
Sep 20, 2004, 1:32 AM
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Dont quote me here, but if I recall correctly, then I read a record in a Guiness book once for the highest fall ever survived. It was by an airline Stewardess that somehow fell to the ground after the plane suffered damage. She fell X thousands of feet and landed in a stingin-ant nest. The ants stung her badly, which somehow lead to electrical impulses in her body which kept her heart beating, being that the heart beats due to electrical impulses. My memory may decieve me, but I thought that this was one hell of a survival story!
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richardr
Sep 20, 2004, 2:09 AM
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Speaking of death in the workplace, I get bored to death at my desk some times, does that count?
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