The biggest problem is he’s engineering in Imperial instead of SI units.
I thought the same way, then became an American engineer. Fuck a horsepower, because it’s so goddamned context dependent.
anon’s in trouble because they’re using psi instead of bar.
Edit: also fuck high pressures are a scary thing.
Pascal FTW.
He is so dreamy
Think you mean mmHg
We have mmHg at home (feet water)
Am I assuming correctly that we’re looking at a big succ-situation, where the diver will big forced through the tube no matter what?
It’s a difference of like 7 psi over an area of what looks like maybe 30 square inches, which would be uncomfortable to get caught in, but I don’t think you’re getting Byford Dolphined
210 lbs will certainly keep you stuck there though
Ahhh yeah that’s where I’ve heard it before, WTYP had an episode on that!
For fun you can search up Delta P to get to industrial horrors beyond comprehension
Ayyyy, a wild Well There’s Your Problem reference. By far my favourite podcast.
from a different reply I understood the meaning of the last two words: https://en.m.wikipedia.org/wiki/Byford_Dolphin
If you were on your back and had your legs above the hole, is 7 psi strong enough that you wouldn’t be able to fight it?
I guess another question would be “how strong would it be compared to gravity?” (if anybody has any idea)
It very much depends on the size of the hole. 7 psi over 1 square inch is 7 lbs, but the same pressure over 100 square inches is 700 lbs.
For a naive estimate, the hole looks around 6 inches wide, which gives it an area of around 30 square inches, so there’s like 200 lbs of water pressure over the area of the hole. An even more naive assumption is that if you were “standing” over the hole in the wall, you would feel 200 lbs of pressure forcing you “down,” which I think most people could easily handle. I’m doing more than that right now!
Unfortunately I don’t know how to even start to calculate the force of the water on you as it rushes past you, but my gut instinct is that it wouldn’t be more than the total pressure in the hole
Is 5m enough for that? I feel like no, but i have no idea.
Yup.
Safety video for anyone with an interest: https://www.youtube.com/watch?v=AEtbFm_CjE0 Delta P is stuff of nightmares.
This unfortunately happened in real life.
Edit: other way around though. The divers were on the air side (habitable quarters) of the chamber.
For more clarification, they were on the high pressure air side. The kind of dives they were doing involved long periods of acclimation to the different pressures involved, so the diving bell was pressurized to 9 atmospheres. Someone fucked up, and the door opened. 9 atmospheres turned into 1 atmosphere very quickly, and the only good thing is that it happened so fast that the deceased wouldn’t have even noticed
If you want to see an episode of a podcast about engineering disasters which is itself, ironically, an engineering disaster, well there’s your problem
Just for what it’s worth, it looks like it was actually an equipment malfunction, not someone fucking up, that caused the accident. The company claimed the person fucked it in an attempt to cover their asses, and they were eventually found to be hiding the truth in a court of law.
Justice should be violent
The families of the divers eventually received compensation for the damages from the Norwegian government, 26 years after the incident.
Well, it’s good that some justice was finally achieved, but that is depressing level of covering up (as usual)
Some parts of that article are straight horror.
👋 not reading it
Same here, I’ll stick to this comment thread, thank you very much.
But where’s Saddam?
Top 10 ∆P incidents
DELTA P 🗣️🗣️
I don’t see the problem.
I mean, I don’t swim, but the dynamics seem to make sense.
What am I missing?
Edit: Ah, don’t go near the water passage, right?
deleted by creator
I just remembered that meme “SpongeBob Experiences Delta-P and Dies Instantly”
Although I’m having a Mandela Effect moment where I swear I saw a version where Patrick talked a lot longer with much more technical information.
https://www.youtube.com/watch?v=PXgKxWlTt8A
Like that, but with people.
Ouch!
And just to think, we’re all gradually evolving into crabs…
no we’re not carcinisation is a vastly overblown meme it’s other crustaceans in similar environments evolving into crab like forms as they already fill the same ecological niche and a crab body is perfect for that ecological niche any other creature is not evolving into crabs I hate the carcinisation meme
This really Byfords my Dolphin
Wouldn’t this human in theory become a crumpled sausage like what happened to the crab by the leaking underwater pipe?
https://en.m.wikipedia.org/wiki/Byford_Dolphin#Diving_bell_accident
Fuck all of this
They also alleged the accident was due to a lack of proper equipment, including clamping mechanisms equipped with interlocking mechanisms (which would be impossible to open while the chamber system was still under pressure), outboard pressure gauges, and a safe communication system, all of which had been held back because of dispensations by the Norwegian Petroleum Directorate.
Fatigue may also have taken its toll on the crew, who had been working for longer than 12 hours
Builder of the rig Aker ASA’s Gross Profit was 7.16B
Norway’s oil and gas tax revenue soars to record $89 bln
Imagine forcing your workers into more than 12h shifts, running on 30 year old equipment, the government straight up refusing to upgrade said equipment, while making billions in profits - they don’t call it gross profit for no reason…
Fuck all of this
Normally when people say this it is at least a bit of an exageration, but not in this case. That is some straight up nightmare fuel.
Heres a taster for those of you who don’t want to read the whole thing.
…bisection of his thoracoabdominal cavity, which resulted in fragmentation of his body, followed by expulsion of all of the internal organs of his chest and abdomen…
You know how often a picture is worth a thousand words?
I feel like those words are worth a thousand pictures. All of them NSFL.
Am I reading the right article? I read the entire wiki article linked above and, quite honestly, the part you’ve quoted here is the only piece that even approaches being gruesome, and is very medically sanitized. What are people referring to when they say that the descriptions made them want to vomit and all this stuff?
The wildest part to me is someone having the last name Coward. The only way that surname makes sense is if it was changed from something worse like Kiddiddler.
Not at 15 feet. I don’t know enough to say how fast the water would be leaving that hole, but it’s maybe a couple hundred pounds of pressure. If he even got caught, it would be super uncomfortable, but he ain’t about to get ∆p’d
If you wanna see a real crab-in-a-pipe situation, look up that Byford Dolphin everyone’s talking about
Let’s convert to metric so we can tell.
15 ft is about 5 m.
Water pressure increases by 10,000 pa per meter (rhogh, rho=1000 kg/m^3, g~10m/s^2), so total pressure is 50 kpa, or 1/2 earth atmospheric pressure.
One side of that hole has ambient pressure of 1 atm. The other side has that plus water pressure totalling 1.5 atm.
A pressure is just an energy density. Multiply by the cross-sectional area of the interface to get the energy gradient across the interface. An energy gradient is a force. We don’t have a measure of the cross-sectional area of the hole, but if we expect a person to fit through let’s call it 1m^2.
50 kpa = 50 kJ/m^3, so total force felt across this opening is 50kN which is the equivalent weight of five metric tons.
Size of the hole absolutely matters. If it’s only the size of a fist (10cm x 10cm) then instead of 5 metric tons it’s only 50 kg of equivalent weight, or about the weight of a person and easily survivable.
Let’s convert to metric so we can tell.
15 ft is about 5 m.
Water pressure increases by 10,000 pa per meter (rhogh, rho=1000 kg/m^3, g~10m/s^2), so total pressure is 50 kpa, or 1/2 earth atmospheric pressure.
This is very interesting. I like unit conversions.
What I did was just take 21-14 psi, and then converted that to bar or atm. I got a number close to ½.
I was like, half an atm? Can’t be that bad? I can handle 1 full mf atm literally all mf day mf.
But I guess that’s different somehow? I just don’t understand how yet. If anyone would care to go into it with me… 🙏
Remember a vacuum does not have suction it’s the air that presses things under vacuum together. One atm is actually quite a lot but we can withstand that as it’s pressing at us from all sides including inside.
The atmosphere is big and heavy. Small pressure changes on order 1% means hurricane. 50% of an atmosphere pushing on something is a lot.
Note, this is all Earth’s atmosphere.
Titan’s atmosphere is energy-denser than ours at 1.5 atm. Titan is Saturn’s largest moon.
Venus has 96 atm. Absolutely crushing and hard to visit at all.
Mars varies from like 0.3-0.6% seasonally as significant portions of its CO2 atmosphere deposit onto the poles as dry ice glaciers in a runaway greenhouse style. CO2 snows out, temps drop, more snows. Keeps going till the sun comes back. Sunlight sublimates the ice back into the atmosphere in a similar runaway fashion. Like a deep breath in and out with the seasons. The weight of all that ice falling and leaving keeps that red lump beating every year. Don’t believe those who say Mars is dead. We don’t know yet. Don’t count out anything with a breath and a beat. What is life on a planetary scale, anyhow?
The gas giants have atmospheric pressures so high it kind of stops making sense to use these as comparisons, and instead we have to look to geology for analogues as deep within the earth we also approach these energy densities.
Yeah I read the entire Wikipedia entry on the Byford Dolphin and I almost threw up because how vivid the description is. I think this would be my third time saying this but that’s not a nice way to go (to die) at all.
You weren’t kidding. Real horror movie shit.
You aren’t kidding that they weren’t kidding. I genuinely felt a bit of a ping of nausea and had to mentally distance myself a bit from imagining it too vividly.
I hope you’ll be able to forget, bud. ❤️
I genuinely had already forgot this and to look what you we’re concerned I’d remember.
I’ve been smoking daily for uhm, a few years now.
Reference: https://www.youtube.com/watch?v=_-INIu_VK08
When it’s got ya, it’s got ya.
Wtf is a psi
Muricas version of pressure.
It would kill you regardless of where you live
Freedom units
pounds per square inch. the us version of bar or n/m²
Why is your comment highlighted blue in Lemmy Connect?
It’s what you need to power your Protoss army
It’s the Imperial Gangnam Style unit
100.000 PSI is equal to 1 bar(if I remember correctly)
Unfortunately no, 1 bar (1 atmosphere) is 100,000 pascal
PSI is pounds per square inch and is roughly 14.5 PSI to 1 bar, and to me, way less intuitive than bar
Ah thanks.
PSI is a nice scale for tire pressure since most tires will be between 20-100 PSI. There’s pretty much never a reason to use decimals, and 5 PSI is the most useful increment.
Bar is probably nicer for a bunch of other things, but for everyday use, PSI has a nice scale. That’s also why I prefer Fahrenheit to Celcius for weather, but Celcius for cooking and science.
That’s metric
no, not at all. bar is a logical metric unit, psi is imperial. because the us doesn’t know what powers of 10 are, there’s never a nice conversion factor.
US uses both and is capable of conversion. It is unfortunate, but saying it doesn’t know powers of ten is pretty condescending.
I said (or at least meant) that imperial doesn’t use powers of ten like metrkc
Word. “The us doesn’t know what powers of 10 are” just didn’t convey that clearly.
We’re stuck with this shit for now, and one of the few positive things is that it forces you to understand both the conversions and power of 10 is cake compared to understanding both and converting.
Yeah I read about it. Definitely not the nicest way to go.
I’m unfamiliar with fluid dynamics. How intense would the Delta p problem be in this situation?
Soup like homogenate
Investigation by forensic pathologists determined that Hellevik, being exposed to the highest pressure gradient and in the process of moving to secure the inner door, was forced through the crescent-shaped opening measuring 60 centimetres (24 in) long created by the jammed interior trunk door. With the escaping air and pressure, gross dismemberment ensued; it included bisection of his thoracoabdominal cavity, which resulted in fragmentation of his body, followed by expulsion of all of the internal organs of his chest and abdomen, except the trachea and a section of small intestine, and of the thoracic spine. These were projected some distance from the bell, with one section being found 10 metres (30 ft) vertically above the exterior pressure door.
Soup indeed.
a section of small intestine
Huh. Weird. I wonder why that stayed in place. I mean, I wouldn’t have thought that you can squeeze out a person like a tube of toothpaste but since that is apparently a thing…
I feel like a delta of less than 10 psi doesn’t sound so bad
It depends on the size of the opening. If it’s small that’s no problem. You could block a 1 inch pipe at 10psi with your bare hand and be largely fine. It’s a little less than 10 pounds of force assuming a round opening.
The problem is that the total force scales geometrically with the size of the opening. Make it two feet wide at the same 10psi and now you’ve got about 4500 pounds of force trying to push you though that opening should you find yourself in the unfortunate situation that it’s been completely blocked by your body.
Yeah fair play to the big opening issue, I was picturing 1-20cm holes
Yeah, the rendering shows it to be about the height of a foot. So probably not too bad.
Yes. As long as the pressure is not enough to put a hole in you, you just need to care about the force.
Big succ P
