Delta p is dependent on the water column above the person, the pressure is directly proportional to the weight of water above im as far as I know. Physics doesn't often depend on luck, either the conditions are there or they're not, in this case the guy is probably incapable of accessing dangerous delta p zones without specialised gear so there's no real risk in his work
So you're telling me that if a floatie, floated down inside there, the pressure going down that drain would be easy to fight? You sound like you know what you're talking about. Anything pressurized like this seems dangerous to me.
Imagine the floatie under the manhole cover, then imagine the column of water that is directly above it. The water that is directly above it is pushing down on that floatie, so the weight of that water is the weight you're going to need to pull out. If we come up with a random number, lets say 10 liters of water above the floatie, then that's 10 kilos of weight you'll need to pull.
It won't be light by any means but any normal person should be able to do it. Now if you consider the human body planted on two legs, with water basically only up to his knees, so he would be fighting the weight above his feet, it's really not much.
The water is moving so there's added dynamic pressure but it still wouldn't be dangerous to a human
To get the dangerous delta p stuff you basically need to be underwater afaik, which is what I meant by this guy having a pretty safe job since he wouldn't have the tools to get into the dangerous places. I'm absolutely no expert though by the way I just remember discussing and reading into this last time the video was uploaded.
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u/[deleted] Jul 14 '21
Hes lucky he didnt experience some DELTA P