Whenever you watch a documentary about deep diving you will always hear the divers talk with a high voice. This is because of the helium they use to reach great depths. But why do technical divers use helium?
The answer to this question is actually surprisingly simple. The divers using helium want to minimize the use of oxygen and nitrogen. As you might know, nitrogen induces nitrogen narcoses and causes long decompression times. Oxygen is no better a great depths, it becomes toxic.
The benefits of using Helium
So to reduce the downsides of oxygen and nitrogen technical divers replace them for a large part with helium. For starters helium doesn’t have a narcotic effect en does not get toxic a great depths. Helium also reduces the decompression time because the amount of nitrogen is reduced. An additional benefit is that helium isn’t as dense as normal air. This makes it easier to breathe a greater depths.
The disadvantages of using Helium
The first thing you might think now is: why aren’t we all diving with helium? Well that’s because there are a number of disadvantages to using helium. For example you need to have a big wallet to dive with helium. An average fill of a 12 liter tank with trimix (gas mix with helium in it) is about $ 20.-.
Common trimix Mixtures
|21/35||which has 21 percent oxygen, 35 percent helium and 44 percent nitrogen|
|18/45||which has 18 percent oxygen, 45 percent helium and 37 precent nitrogen|
Secondly helium is prone to release bubbles more easily than nitrogen does. This means that if you make an uncontrolled ascent you are more likely to get the bends with helium than you might be when using normal air. Wanna know more about decompression sickness? Click here for a complete explanation.
The last disadvantage is that helium is a great warmth conductor. So when you fill up your dry suit with a gas mixture containing helium you will get cold much earlier. That’s why a lot of technical divers also wear a bottle of argon solely to put into their dry suit to isolate them.