Daily Diving Dilemmas Dexterously Defeated (Part 4)
While diving, there is far greater pressure acting upon the human body than at sea level. A diver that is 33.8 feet below water experiences twice as much pressure as they would at sea level. Each foot that the diver descends into the water will add 0.445
psi of pressure onto the diver. The deepest open-sea dive in history was recorded at 534 meters, or 1,751 feet, performed by a team of Comex divers as part of the Hydra 8 program. Since pressure is 14.7 psi at sea level, the team of divers was experiencing
793.9 psi or 54 atm. That means that the pressure experienced by the divers at 1,751 feet below the surface was 54 times the pressure at sea level. At this depth, oxygen becomes toxic, and without proper protection, the diver’s body would be crushed due to
the immense pressure. Pressure damage is one of the main side effects of diving, if the diver is not trained.
Pressure damage, or barotrauma, usually results in eardrum damage. Barotrauma is bodily damage to body tissues as a consequence of a disparity in pressure amid an air space inside the body and the surrounding fluid. Once the eardrum is damaged, cold water
enters the inner ear and chills it, resulting in disorientation and dizziness. This can be caused by different pressure within the ear and the surrounding water. To prevent this from occurring, a diver must never dive if they have congestion, such as from
a cold. Also, proper training in clearing the ears is required. Aside from this, if the diver is wearing a hood, the hood must not cover the ears. Furthermore, a diver must never wear ear plugs. The common cold can also cause damage to the sinus due to pressure.
Greater pressure can also cause squeeze damage in the eye’s blood vessels. This is caused by suction from the air space within a mask, known as “mask squeeze.” To overcome this, the diver must occasionally exhale through the nose, which adds more air into
the mask, equalizing pressure. However, exhaling through the nose too much is not a problem, since the diver will only be able to exhale so much before the equilibrium in pressure prevents them from doing so. Also, one must never dive with eyes-only goggles.
Apart from the eyes, squeeze damage can also be caused on the skin under a drysuit, again due to an imbalance in pressure. Modern drysuits have a method to prevent this, by using the air inside of the cylinder to inflate the drysuit to maintain equilibrium
in pressure.
While snorkelling, blood may become present within the lungs, known as “lung squeeze,” due to diving too deep while snorkelling. To prevent this, divers should utilize and underwater breathing system. With the old full-body diving dress, “helmet squeeze”
would also occur. If a valve malfunctioned or failed in the helmet, an instantaneous increase in pressure would occur, resulting in the diver’s body would be mangled and compacted within the helmet.
This occurrence has been confirmed on Discovery Channel show, Mythbusters, in which the scientists immersed a diving dress with a mock-body in 300 feet of water. At this depth, there was 9.2 atm, or 135 psi of pressure, which was equalized through surface-supplied
air. When the air pressure was cut off, the body was crushed instantly and moved upwards towards the helmet. If this happens to a human, they would suffer a quick and painful death, as their bones, organs, and tissue would be pulverized.
The idea of a diver’s body being crushed into something that resembles ground beef is a disturbing and uninviting image, but this occurrence was only reported a few times during the course of history. These days, diving dresses are only used by historical
divers and collectors. Modern drysuits keep this from happening, as they have fail-safes to keep the divers at a comfortable and safe pressure.
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