Please somebody know what I’m talking about. If not, then please see the diving bell incident in the link provided below. I just don’t see how you are killed by air.
https://en.m.wikipedia.org/wiki/Byford_Dolphin
In: Physics
Gas is always trying to equalise pressure. That means that when something is pressurised to 9 bars (atmospheres) in a 1 bar environment, it’s pressing against its container with 8 bars of force. And unlike a liquid, it’s pressing in all directions at once. Gas under pressure will find the weakest point in its container; it’s why gas explosions are so dramatic. Note that scientifically, both liquids and gases are considered ‘fluids’ because both have some common behaviours they both display; under certain conditions, gases can behave like liquids, and vice versa. When highly compressed, gases suddenly start looking a lot like liquids.
1 bar is equivalent to 14.7psi. So every square inch basically has a weight of 14.7 pounds applied to it. At 9 bars, it’s 132.3 pounds on every square inch of exposed surface. The outside is pushing back with 1 bar, hence the 8 bar difference. So the air inside the chamber was pressing against the entire surface with 117.6 pounds per square inch.
Because the gas is always pushing, the instant a hole opens, it’ll find that hole and escape. What happened in the Byford Dolphin was, the trunk where the diving bell connected formed a bottleneck. You know how if you’re spraying water through a hose and pinch it, the water shoots further? Same principle. Less air flows through a bottleneck, but at higher speed. So you have a lot of high pressure air, which is already pressing outwards with a huge amount of force, suddenly being released. It’s just like shaking up a bottle of soda and then pulling the cap off – the higher pressure inside the bottle escapes explosively. And that’s only a small pressure difference. As air equalises pressure, it expands, (pressure is inversely proportional to volume) so again, pushing in all directions, it creates a shockwave.
The very unfortunate diver who was closing the trunk reduced the bottleneck even further, adding more pinch to the hose. So the high-pressure air behind him instantly escaped through the hole, applying all that pressure to whatever is in the way. Like a battering ram, force is mass multiplied by acceleration. And air does have mass; at 9 bars, the same cube of air weighs 9 times what it does at sea level. The air has been squashed into a smaller box.
And because there was already air in his lungs at 9 bar, it immediately escaped as well. The human body is not designed to handle rapid changes in pressure; very gradual, controlled changes are possible, but rapid changes will cause horrific damage. That’s why divers have the diving chamber in the first place. The human body isn’t strong enough to withstand huge pressure differences, so the high-pressure air within his body, when exposed to the lower outside pressure… well, it chose the quickest way out to equalise, it doesn’t care what’s in the way. Really nasty.
The other resting divers were killed by the same thing – the diving chamber suddenly went from 9 bars to 1 bar, causing horrific internal injuries as the air inside them expanded.
Compressed air is incredibly dangerous. For something so vital to life, it has been the cause of unexpected injuries, deaths and damage. A great illustration is an exploding tyre – something so everyday and benign? If air escapes a pressurised container suddenly, the damage it can do is staggering.
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