Why not 60% O2 for prof during OW?

RonzoTheGreat · Feb 23, 2009

Hello all,
Why not use 60% O2 for professionals during OW? If you are shallow for all of the dives, what are the drawbacks of diving less nitrogen as a professional?

This is somewhat of a rhetorical question but I want opinions as well.

Thanks in advance.

Dtaine · Feb 23, 2009

RonzoTheGreat:
Hello all,
Why not use 60% O2 for professionals during OW? If you are shallow for all of the dives, what are the drawbacks of diving less nitrogen as a professional?

This is somewhat of a rhetorical question but I want opinions as well.

Thanks in advance.

Not a dive professional, but I could imagine that cost & availability would be a consideration - air is cheaper and sometimes it can be hard to get richer fills.

JeffG · Feb 23, 2009

Why?

There is no big rush of bent dive instructors, so why bring in all the dangers of O2.

There is no problem to solve.

Gombessa · Feb 23, 2009

RonzoTheGreat:
Hello all,
Why not use 60% O2 for professionals during OW? If you are shallow for all of the dives, what are the drawbacks of diving less nitrogen as a professional?

OW classes are usually held in 20-30ft of water. At that depth, your NDL is essentially limitless (it's already something like 3 hours at 40ft), so the benefits would seem to be trivial. There are some agencies that will teach OW on 32% or whatever blend of nitrox they've established as standard for a recreational profile.

SteveAD · Feb 23, 2009

Just off the top of my head:

*60% would require all regs and tanks to be fully o2 clean
*60% is generally not a commercially available fil
*60% (if it became available) would be a relatively expensive fill
*60%would have an MOD of 44 feet (at 1.4 ppo2) or 55 feet (at 1.6ppo2) which could prevent an instructor from reaching depths well within the standards for an OW class.
*Nitrogen loading on air is pretty negligible for an instructor running OW classes

JDostal · Feb 23, 2009

We do often use oxygen rich mixtures. 40% when doing checkouts is common especially on a day when they are doing their CESA drill. 60% is a little high but the 40% can be nice. Makes you feel a little less wiped out at the end of the day too.

ianr33 · Feb 23, 2009

Most "Dive Professionals" are not certified to use 60%.

String · Feb 23, 2009

RonzoTheGreat:
Hello all,
Why not use 60% O2 for professionals during OW? If you are shallow for all of the dives, what are the drawbacks of diving less nitrogen as a professional?

This is somewhat of a rhetorical question but I want opinions as well.

Thanks in advance.

Reverse the question - what would the benefits be over say 40% or even air?

Anti-Hero · Feb 23, 2009

RonzoTheGreat:
Hello all,
Why not use 60% O2 for professionals during OW? If you are shallow for all of the dives, what are the drawbacks of diving less nitrogen as a professional?

This is somewhat of a rhetorical question but I want opinions as well.

Thanks in advance.

Like mentioned above 02 exposure would be the biggest limiting factor. For example:

PP02 = 0.60*(44/33+1) - At 44 fsw you would be running at 1.4 PP02, the recreational limit for a working portion of a dive. At that PP02 you would have 180 min. (3 hr.) of exposure for a 24 hour period.

Another limiting factor would be (like also mentioned above) running 60% 02 would require extensive oxygen cleaning of all equipment, and would also be expensive to fill.

If an instructor was going to use Nitrox, EAN32 would be the preferred choice. You would still get decreased N2 loading, longer bottom time, less deco stress, and it's common, cheap and easy.

Hatul · Feb 23, 2009

RonzoTheGreat:
Hello all,
Why not use 60% O2 for professionals during OW? If you are shallow for all of the dives, what are the drawbacks of diving less nitrogen as a professional?

This is somewhat of a rhetorical question but I want opinions as well.

Thanks in advance.

As someone else pointed out, at shallow depths where 60% could be used the benefits would be trivial, and the cost great. You need special regulator and tank, and then there's the cost of the gas.

Adam

Why not 60% O2 for prof during OW?

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