SCUBA DIVING CONCEPTS YOU’VE NEVER LEARNED OR PROBABLY FORGOTTEN- PRESSURE
Scuba diving is as much a practical venture as it is theoretical. In this article, we will be taking a look at five basic concepts which every scuba diver needs a thorough understanding of.
THE EFFECT OF PRESSURE ON DIVERS
Pressure changes underwater and this change affects certain aspects of scuba diving, but before taking a look at exactly how air pressure affects these aspects of scuba diving, we will agree on two things- air has weight and pressure increases with depth.
Now that we agree on those basics let’s examine the aspects of scuba diving air pressure effects.
EQUALIZATION– Equalization prior to taking a dive is necessary to avoid the pain and injury which occurs as a result of a change in pressure when diving. This pain can result from pressure on the eardrums or lungs during a decent or an ascent. To avoid these pressure-related injuries, a diver must equalize the pressure in their body’s air spaces with the pressure around them.
BUOYANCY- Divers can control their position in water by adjusting their lung volume and buoyancy compensator (BCD). They can either be positively, negatively or neutrally buoyant depending on the air in their lungs or their BCD.
When making a decent, a diver should decrease their air pressure on their BCD, and when making an ascent, the reverse should be done.
BOTTOM TIMES- Bottom time refers to how long a diver can stay underwater before they begin their ascent. Pressure affects bottom times in two significant ways: an increase in air consumption reduces bottom times and what this means is that if a diver takes in more air, they breathe out more thereby reducing the time they spend underneath the water. Same goes with increased consumption of Nitrogen, therefore, a diver can only allow a certain amount of nitrogen absorption before they begin their ascent or they face a risk of decompression illness if they don’t make the necessary mandatory stops.
RAPID CHANGES IN PRESSURE CAN RESULT IN DECOMPRESSION ILLNESS- An increase in underwater pressure can cause a diver’s body to absorb more oxygen than they would do when on the surface. If a diver descends slowly, the nitrogen gas expands slowly, and the excess nitrogen is safely eliminated from the diver’s tissue and blood and their nostrils when they exhale.
However, this method of removing excess nitrogen is limited especially when the diver goes through a change in pressure too quickly. Their body will not be able to eliminate the excess nitrogen fast enough, and this results in decompression illness with the primary symptoms being a block in blood flow around the body, stroke, paralysis, and other life-threatening problems.