 |
|
Adding helium to the mix often makes the dive safer, especially during deep dives, because of the characteristics of helium. When we dive below 30 meters, helium has the following three advantages:
-Helium is less narcotic then nitrogen or oxygen; we therefor experience less nitrogen narcosis.
-Helium is less dense then nitrogen or oxygen; the mix has a lower breathing resistance.
-Helium off-gasses quicker then nitrogen; we have a better and quicker decompression.
The fact that helium is less narcotic is reason enough to choose helium as part of the mix. Deep air diving is still the main cause of diving accidents; by adding helium to our mix we can avoid the problems associated with deep air diving. We avoid the usual symptoms of nitrogen narcosis: impaired judgement, lowered reaction speed, altered consciousness, by adding helium.
The lower density of helium is another good reason to use it, because when we use air at depth, we experience higher breathing resistance, and therefor a higher chance of "hypercapnia." "Hypercapnia" is a buildup of carbon dioxide in our body, that can cause hyperventilation and, in extreme cases, unconsciousness. Adding helium to the mix is a simple and effective method to avoid these serious problems.
The last benefit is that helium off-gasses quicker then nitrogen. Decompression theory is a difficult subject, but by using helium as part of the mix you can do a quicker and safer decompression then when you use air for your deeper dives.
Helium has two negative sides, which do not offset the benefits, but which need to be mentioned here. One is the high cost of helium, the other the fact that helium is a good thermal conductor.
Using helium-mixtures is more expensive than having your tanks filled with air. Especially in areas where it has only been introduced recently, helium is very expensive. But still, what price can you put on having a bigger chance to have an accident? Do you want to pay with money or do you want to pay with your safety?
Helium is a good thermal conductor, which means that when you use a dry-suit you cannot use the helium-mix as an inflation gas for your dry-suit. The common solution is to take a small tank with either air or argon, and use this as inflation gas during the dive. That means an extra tank and regulator, extra equipment, and extra money that needs to be invested. I think that in the long run this is a very good investment.
When you look at the negative sides of helium; the costs and the higher thermal conductivity, and the positive sides; less nitrogen narcosis, comfortable breathing, and quicker and better decompression, then the pros out-weight the cons. Then you understand why George Irvine states: "Helium is our friend."
PS:This is a partner-site of www.scuba-diving-links.com, the biggest and most up-to-date scuba diving links directory on the Internet. Check it out!
