Mixed gas training can be broken down into several different classifications. There is no class or certification called “mixed gas.” Mixed gas is typically classified as the combination of helium, nitrogen, and oxygen, which is called trimix or just helium and oxygen, which is called heliox. Trimix is quickly becoming the more popular mix for technical divers today.
The dive training community offers a number of different “mixed gas” certification courses as well as different levels of courses. Training organizations, such as TDI, IANTD, GUE, NAUI, or GUE all offer training courses with various names and levels. When looking for mixed gas training, the following are some of the courses you might find.
· Trimix I
· Trimix II
· Entry Trimix
· Advanced Trimix
· Recreational triox
· Normoxic Trimix
· Trimix mixing technician
· Advanced gas blender
Generally, the entry level or beginning trimix courses provide the training required to competently and safely utilize breathing gasses containing helium for dives that require staged decompression, utilizing nitrox and/or oxygen mixtures during decompression to a maximum depth of 200 or 225 fsw (60 or 68 msw).
Advanced level courses provide the training required to competently and safely utilize breathing gasses containing helium for dives that require staged decompression, utilizing nitrox and/or oxygen mixtures during decompression to a maximum depth of 300 fsw (91 msw).
Normoxic trimix is rapidly catching on in the technical diving community. Normoxic trimix is for divers who wish to dive between 130 and 200 fsw (39 to 60 msw), but who don’t want to breathe air at those depths. Normoxic mixtures generally keep the oxygen content at 21%, just like “normal” air but by adding helium, reduce the effects of nitrogen narcosis and reduce decompression times.
Mixing technician and gas blender courses provide you with the skills, procedures, and knowledge needed to safely handle high-pressure gases and prepare EAN and helium based gas mixes for use by divers. You learn how to prepare and blend high quality gas mixes. In addition, you may also learn the skills necessary to clean, test, and document the testing of equipment used with high levels of oxygen.
Depending on your current experience and where you want to go with technical diving, it is important to research and understand the courses offered for mixed gas training. Each training agency has different requirements, procedures, and methods of teaching. Find the one that best fits your needs and goals.
Not all dive shops offer mixed gas training. Typically, only dive shops that categorize themselves as “technical” shops offer this type of training. You may have to travel out of your area to find a dive shop or instructor. Once you find an instructor, find out the instructors experience level, how many “mixed-gas” dives he/she has, and how and where they train. Getting the right instructor is extremely important and can be the difference in really learning something and just getting by. You don’t want to “just get by.”