Deco Proc Course Gear Requirments

[cold_diver]

Hello,

Can someone at TDI please give me the definitive answer on whether or not the deco proc course requires doubles or not?

Yes, or no; Can the deco proc course be taught with a single tank and single deco/stage cylinder if the stage/deco cylinder is breathable at deepest depth?

Thanks,

brrrrr........

 

[Dive-aholic]

I'm not at TDI, but I do have the TDI standards manual and doubles are not required. However, redundancy is and I believe each instructor can add their own requirements.

 

[wedivebc]

Minor hijack alert, Doppler, TDI, anyone, why doesn't TDI post their standards for all perspective students to help prepare themselves? It used to be on the TDI Canada web page before they closed shop.

 

[captndale]

Minor hijack alert, Doppler, TDI, anyone, why doesn't TDI post their standards for all perspective students to help prepare themselves? It used to be on the TDI Canada web page before they closed shop.

TDI does not post their standards for prespective students because their standards are for their instructors. Their standards are the minimum standards that their instructors must adhere to. Each instructor sets their own standards for their students. If you want to know what is required for a particular course you should ask your instructor.

 

[Steve SDI/TDI HQ]

Hello,

Can someone at TDI please give me the definitive answer on whether or not the deco proc course requires doubles or not?

Yes, or no; Can the deco proc course be taught with a single tank and single deco/stage cylinder if the stage/deco cylinder is breathable at deepest depth?

Thanks,

brrrrr........

Course may be taught with a single and an H or Y valve. Final gear configuration will depend on local conditions, depths at which course is to be conducted, and duration of dives and all members of dive team staying within acceptable gas management rules.

The original poster dives on the east coast... well, for a point of reference, the majority of our instructors in North America teaching this course on open-circuit would have candidates on manifolded doubles. I've been teaching it for many years and can only recall two students who did it on high-volume singles and an H valve.

As to the question raised by OP about redundancy being supplied by deco gas that can be breathed at maximum depth... Not the best plan at all for two reasons.

Optimal decompression. Decompression Procedures is normally taught in conjunction with Advanced Nitrox which allows for high-oxygen content decompression gas to be used. This practice is commonplace because we believe it optimizes off-gassing.Having a deco gas and bottom gas delivering the same, or very similar partial pressures of inert gas on ascent is out of sync with that practice. In some cases, deco is taught as a stand-alone and in this case, the maximum allowable nitrox mix will reflect that allowed under the auspices of the student's basic nitrox training. Usually then, air will be used as a back mix and something like EAN39 as a decompression.

Concerning CNS toxicity. Not having a redundant BOTTOM GAS (that's to say a mix with an MOD equal to or exceeding maximum target depth for the dive) breaks standards and good sense. Bailing out to a hot mix is neither tolerated by standards nor is it an acceptable practice.

Having said all that, in practice, the course COULD be conducted no deeper than the MOD of EAN39 and that COULD be used in the event of a primary gas failure (simulated or real), but it would make OOA buddy drills complex and untenable.

 

[wedivebc]

I am aware of that. I want to know what the reasoning is behind it.

TDI does not post their standards for prespective students because their standards are for their instructors. Their standards are the minimum standards that their instructors must adhere to. Each instructor sets their own standards for their students. If you want to know what is required for a particular course you should ask your instructor.

 

[captndale]

I am aware of that. I want to know what the reasoning is behind it.

I do not presume to know the reasoning behind it but I am happy that I do not have to engage in defending every requirement I set for my students. Publishing the minimum standards encourages some students to think that they deserve to be certified if they accompish the bare minimum that the agency sets forth. That may be the case for some other agencies but I, for one, am quite happy that it is not the way that TDI works.

 

[Steve SDI/TDI HQ]

I am aware of that. I want to know what the reasoning is behind it.

At least part of the reasoning is that posting standards seems to confuse the issues. In the past when TDI first began operations, we posted them freely and it caused no end of grief for everyone involved. The issues were many-fold: first off standards for a single course as a standalone are intended for professional level members and usually have some sort of overriding standard of precursory standard that they are associated with. As a stand-alone some standards therefore seem incomplete and some seem overly restrictive. Certainly we found that students reading standards (which are worded in very specific way and almost always only set minimum requirements) caused issues because an instructor would include a skill he or she deemed necessary in their environment for a pass. But if it was not mentioned in the course standards, students who failed to perform at the level their instructor deemed a pass, complained.
We are updating our diver information website to give candidates for courses a more complete understanding of what will be expected of them to graduate a class and what a “typical” course may consist of.

 

[Scuba Cowboy]

I'd like to hear back from the OP why he would want to do decompression diving in anything other than the accepted norm for that type of diving. I'm one of the TDI Instructors who requires doubles for this course. It is a technical diving course, and I teach it in technical diving equipment. My feeling is if you are taking a Decompression Procedures course, you want to do decompression diving. And it is my job to see that you learn it in the right way, using a gear configuration that is safe. IMO, a single tank on a deco dive does not give redundancy for all scenarios and is a poor choice. Why would we want to teach a student to conduct dives in anything but the safest and smartest configuration? It is also my opinion that if you for some reason don't want to use the best equipment available for decompression diving, then maybe this type of diving is not in your best interests.
I do not believe there is any room whatsoever for shortcuts in technical diving. Bad things happen to those who take them.

 

[wedivebc]

I'd like to hear back from the OP why he would want to do decompression diving in anything other than the accepted norm for that type of diving. I'm one of the TDI Instructors who requires doubles for this course. It is a technical diving course, and I teach it in technical diving equipment. My feeling is if you are taking a Decompression Procedures course, you want to do decompression diving. And it is my job to see that you learn it in the right way, using a gear configuration that is safe. IMO, a single tank on a deco dive does not give redundancy for all scenarios and is a poor choice. Why would we want to teach a student to conduct dives in anything but the safest and smartest configuration? It is also my opinion that if you for some reason don't want to use the best equipment available for decompression diving, then maybe this type of diving is not in your best interests.
I do not believe there is any room whatsoever for shortcuts in technical diving. Bad things happen to those who take them.

Since the OP is not a tech diver how does he know the single tank is not the optimum choice? That was probably why the question was posed here. It should be the responsibility of the instructor to inform him of that. There are applications when a single tank might be the best choice.