nitrox MOD/TOD

[Thalassamania]

Ah H2 ... ad hominem and half-cocked, always a volatile combination.

Might I humbly request that you turn to Section 3.2, Paragraph E. where it states, "The Maximum Operating Depth (MOD) based on a maximum PO2 of 1.6 atm, of each breathing gas/cylinder (other than air) must be displayed in 3 inch high letters along the side of the cylinder..."

Now you, in your scurry to find fault, skipped ahead to 6.3B, which states, "The maximum operating depth for a given gas mixture shall be based on the oxygen partial pressure of the gas and shall not exceed 1.6 atmospheres of pressure."

So, indeed, you MAY dive to whatever shallower depth you want, but you MUST have a depth on the side of your tank in 3" letters that references 1.6 atmospheres of oxygen. This number is usually referred to as the "MOD."

 

[H2Andy]

Now you, in your scurry to find fault, skipped ahead to 6.3B, which states, "The maximum operating depth for a given gas mixture shall be based on the oxygen partial pressure of the gas and shall not exceed 1.6 atmospheres of pressure."

lol... dude... add 2 and 2 here

why would NOAA allow you to calculate maximum operating depth based on
something less than 1.6, and call it "maximum operating depth" if it's not
"maximum operating depth?"

what if you want to calculate yoru MOD using 1.4?

clearly, 6.3B permits this, and is the exception that swallows the rule (3.2)

in other words, you can calculate MOD based on anything so long as it's not over
1.6.

i see your point, and perhaps a little less arrogance might have gotten along further.

bottom line is, even according to NOAA standards, MOD is not set in stone at 1.6

 

[Thalassamania]

Bottom line is that the MOD goes on your cylinder and is 1.6atm, no ands ifs or buts.

I'm sorry H2 ... I see no arrogance in the posts, a particular point of view ... yes, a particular set of experiences ... yes, a particular suite of knowledge ... yes. If you consider that arrogance, well ... this thread has turned into an apologia on your part for not being quite in command of the English language.

Now you want arrogance? It would have thought it arrogant to have written, "show me your NOAA Working Diver Certificate and I'll show you mine." But then, I try not to stomp on conversations with those sorts of Deus ex machina finales. I don’t always succeed, but I do try.

 

[H2Andy]

hey, i might have called it wrong ... just seemed that way to me

but from my point of view, even NOAA describes MOD in terms other than 1.6

maybe they need to clarify their materials

 

[Thalassamania]

I'd be the last to suggest that governmental prose are less than obtuse at times.

 

[BarryNL]

Bottom line is that the MOD goes on your cylinder and is 1.6atm, no ands ifs or buts.

The bottom line is that the NOAA is not the regulatory body for SCUBA diving in the US and certainly not for the rest of the world. The problem is that, as there is no authority globally accepted, that different agencies and even different clubs have different standards.

The important thing is always to be aware of the standard being used in whatever diving you're doing, and the standard that's been used to mark the bottle you're using if it's not your own.

Trying to claim your own standard as the "right" one will only earn you respect in the DIR community.

 

[The Kraken]

Thal,

I tend to side with Andy on this one . . .
" "The maximum operating depth for a given gas mixture shall be based on the oxygen partial pressure of the gas and shall not exceed 1.6 atmospheres of pressure."

What you have here is the "maximum" of maximums.
The MOD is based upon the PPO2 of the gas. This is established by the diver. It may be 1.4, or 1.43, or 1.51, or 1.5 . . . ad infinitum. That is the MOD as defined by the diver.

Now the NOAA recommends that the PPO2 not exceed 1.6.

If we are diving and we determine that we'll use as our MOD 1.45, then that is the MOD, not 1.6.

By saying that the MOD is 1.6 and 1.6 only, you mutually exclude any lesser values as being set as the MOD and, as I hope you would agree, that simply is not, and cannot be the case.

the K

 

[jonnythan]

Bottom line is that the MOD goes on your cylinder and is 1.6atm, no ands ifs or buts.

According to the NOAA, which I believe has no authority over much of anything related to SCUBA diving, including the training agencies which appear to be teaching most students to use the MOD for 1.4.

 

[Thalassamania]

I really don't understand you people. The OP notes that there is a lack of clarity with the definition of MOD. I point out that the folks who coined the term defined it. And at least three of you seem to feel that the originator of the term has not right to their definition because said originator has no enforcement power over scuba. Way too strange for me.

"The mind's deepest desire, even in its most elaborate operations, parallels man's unconscious feeling in the face of his universe: it is an insistence upon familiarity, an appetite for clarity."
-Albert Camus

 

[The Kraken]

Problem is . . . there's the difference in what governmental bodies intend to say and that which they actually say.

I was just looking at it from a logical standpoint.

One presents a hypothesis. If there can be one instance found to prove the hypothesis false, then the hypothesis is false.

I choose as my MOD for EAN30 a PPO2 of 1.4.

QED

the K