IANTD Normoxic Trimix Diver Course


This Program is designed to train those who wish to dive to depths between 39 msw and 60 msw, but who do not wish to breathe air below 39 msw. Trimix affords a means of reducing narcosis on dives to such depths.
The knowledge and skills taught in this program are more than adequate to qualify divers to perform Trimix Dives outside of training up to 60 msw.


Must be qualified as an IANTD Advanced EANx Diver. Divers qualified as Technical Diver, see note below under Program Content section.
Must provide proof of a minimum of 100 logged dives, of which at least 30 were deeper than 27 msw or sufficient experience doing technical dives to satisfy the instructor that the student has the ability and knowledge to continue into this level of training.
Must be a minimum of 18 years of age.

Program Content

All academic portions of the IANTD Technical Diver Student Workbook and appropriate specific Rebreather materials and reference text material from the IANTD Technical Encyclopedia and all lectures completed with IANTD Course-specific Slides pertaining to the theory in the IANTD Normoxic Trimix Diver Student Kit.
This Program must include a minimum of two Air or EANx or Normoxic (or greater than 18% oxygen) Trimix gas in OW (or overhead environments if the diver is already qualified or if taking this Program in conjunction with a cave or wreck course) to depths not to exceed 39 msw. On all of the dives the student must manage only one decompression cylinder.
This Program must also include a minimum of two dives in OW (or overhead environments if the diver is already qualified or if taking this Program in conjunction with a cave or wreck course) on Trimix using one gas switch. These dives may be performed at depths between 39 msw and 60 msw. All dives must follow or use as backups to a dive computer the IANTD Tables using one gas switch. Dive computers with gas switching capability are recommended. Dives may be made on custom software generated tables provided it is a Program approved by IANTD.
This Program must include a minimum of 220 minutes of run time and a minimum of 4 dives using Air, EANx or Trimix.
To complete the course within the minimum specified dives. With 2 or more additional dives the student may graduate from the course with an overall average score of 6 points

NOTE: Divers who are already qualified as Technical Divers or Cave Divers or IANTD Wreck Divers may have the 2 air or EANx dives credited and only need to do the 2 Trimix dives between depths of 39 msw and 60 msw. Plus complete the lecture on Normoxic Trimix in the workbook

Equipment Requirements

IANTD Normoxic Trimix Diver Student Kit.
Fulfill all Equipment Requirements as specified in the general Technical Diver Programs overview. These courses may be taken with a student on a Rebreather.

Program Limits

There may be no more than 4 students per Instructor. This ratio may be increased by 2 students (for a maximum of 6 students) with an assisting IANTD Trimix Diver Supervisor. If the course is conducted in conjunction with a Cave or Wreck Programs, the limits for those Programs will prevail.
Only one decompression cylinder may be used in this course.
No dives may be conducted to depths greater than 60 msw. .
Oxygen partial pressure may not exceed 1.40 during the working portion of the dives, nor exceed 1.61 ATA during the decompression portion of the dives.
Normoxic Trimix dives must be conducted using a mixture containing at least 20% oxygen (± 1%),
Equivalent Narcosis Depth (END) may not exceed 36 msw.
Surface oxygen must be available for use in the event of Decompression Illness (DCI).
All dives must be performed as a single dive team.
All appropriate safety or required decompression stops must be performed.

Water Skills Development

A confined water session must be completed before conducting any OW dives.
Swim with full underwater equipment (except stage cylinders) for at least 5 minutes.
Become proficient in the following propulsion techniques: modified flutter, modified frog, modified dolphin and standard shuffle kicks.
Deploy lift bag in less than 1½ minutes, and repeat at least 5 times during the Program.
Swim a distance of at least 23 meters without wearing a mask.
Practice removing and replacing a stage cylinder. Must be completed at rest and while swimming.
Have 2 divers swim side-by-side, in full equipment, simulating an out-of-gas situation (without breathing, and exhaling slowly), for a distance of 18 meters, then stop and begin breathing with one diver handing-off the long second stage hose to the other diver. Divers should remain a rest for 3 breaths, and then swim at an average pace for at least 10 minutes. On Rebreathers this drill should be done with the diver breathing from the stage cylinder.
Remove the harness and cylinders from a simulated unconscious diver in less than 1½ minutes. (Students who exceed the time limit on this skill must have a quick-release added to their harness).
Divers using a quick-release on their harness or backpack must, in confined water, swim the system while the instructor disconnects the quick-release to simulate a failure. The student is to swim the system demonstrating control of buoyancy and body positioning with the quick disconnect released for sufficient duration to satisfy the instructor that this type failure may be managed by the student.
Demonstrate an ability to respond to a single-bladder BCD failure by the two methods listed below. (Students using gear configurations that prevent accomplishment of these two skills will be required to wear a redundant BCD. Students who already have a redundant BCD or dry suit may use one of these alternates after attempting perform the methods without the use of the alternative.)
a. Completely deflate BCD and swim while maintaining buoyancy control for at least two minutes.
b. Completely deflate BCD, ascend safely to the surface, and remain afloat for at least 3 minutes.

NOTE: If at any time the student starts to over-exert, or if it is obvious that the skill cannot be accomplished, the instructor is to ensure that the BCD is inflated.

In confined water, have a student lose buoyancy by deflation of the BCD and then attempt to utilize a lift bag or other secondary buoyant device as a BCD.

NOTE: This skill is to demonstrate how effective these devices are and to reinforce that even if not suitable for a redundant BCD they still provide an option for self rescue in an emergency situation.

Following a means of reference (pool wall, guide line, ship railing, etc.) with eyes closed, remove stage cylinder and swim a distance of at least 4.5 meters. Reverse direction, return to stage cylinder and replace it on correct side.
Two divers approximately 18 meters apart, with blacked-out masks or eyes closed, and while simulating an out of air situation, locate each other (using side of pool, rail on wreck, guide line, etc. for orientation) and begin gas sharing via long hose.
Prior to dives, students must use IANTD Gas Management Charts to match gas turn points.
Open and close tank valves at least once on all dives.
At least once on each dive, Instructor is to signal to student(s) that one of their regulators is malfunctioning and the student is to take the corrective action (Open Circuit only).
Perform gas sharing in one form or another on at least 3 of the air dives. It is recommended that the Instructor do this at times when it surprises at least one of the divers, and at a point when there is a reasonable distance between the divers. Determine RMV and demonstrate ability to calculate and perform gas matching. (Open Circuit only)