Question - Nitrox

[mania]

My friend during the Nitrox course found this:

UPTD=BT*PPO2*Kp

If I understand well

UPTD - unit pulmonary toxic dose
BT - bottom time
PPO2 - oxygen partial pressure

but what is Kp?????
We are not able to find it out. He was suppose to do this:

O2 load

Nx32; D=33m; BT=20min

PO2=FP*P=0.32*4.3=1.376 (ok. 1.4bar)
MOD(1.45)=[(PO2max/FO2)-1]*10=[(1.45/0.32)-1]*10=35m
NOAAO2limit=NOAA1.4=150min
%CNSO2=(BT/NOAAO2limit)*100=13,3%
UPTD=BT*PO2*Kp=20*1.4*1.36=45,6

Do you know what is Kp????
PLease help!!!!
Mania

 

[Doppler]

Firstly, one should ask why a nitrox student is being asked to calculate anything to do with Pulmonary Toxicity... it simply is not an issue with recreational use of nitrox (one miught argue the same with most technical expousres too) and simply muddies the REAL issue CNS oxygen toxicity.

That said, the "formula" for calculations is:

OTU = tx X (0.5 /p02 - 0.5) -0.8333*

where tx is exposure time, p02 is whatever constant you get from your exposure depth calculation and -0.8333* is an exponent (you'll need a scientific calculator)

In my experience teaching this stuff to divers for many, years, only engineers, research scientists and people with math and physics degrees on their resumees remember what an exponent is.... what I mean to say is this... IT'S SIMPLY TOO MUCH TROUBLE TO CALCULATE THIS STUFF.

However, to get back to the question.... well, see above.

 

[Dr Deco]

Hello mania:

It would appear that someone is giving a very complete class and covering even pulmonary toxicity. As mentioned above by “Doppler,” this will not really be a problem unless the diver is involved in some very long technical dives, e.g., cave diving.

Dr Deco :doctor:

 

[mania]

Well, u have to understand that although in Poland all the agencies are present the strongest one is CMAS. Those guys are a bit crazy and trying to proof that they are the best, so they teach a lot of stuff I'm not sure that is really needed - at least at the level of CMAS P2. But the funniest thing was that even the instructor didn't know what the Kp is....
By the way CMAS is in Poland the only organization that have the right to regulate the diving environment - generally of course the law is passed by the Polish parliement but written by CMAS guys. So we do have a war between CMAS and PADI. Most of the CMAS instructors are doing everything to proof that PADI is worse and doesn't teach properly despite all the global agreements.
But anyway I'm living in a strange country...
Mania

 

[Doppler]

mania once bubbled...
Well, u have to understand that although in Poland all the agencies are present the strongest one is CMAS. Those guys are a bit crazy and trying to proof that they are the best, so they teach a lot of stuff I'm not sure that is really needed - at least at the level of CMAS P2. But the funniest thing was that even the instructor didn't know what the Kp is....
By the way CMAS is in Poland the only organization that have the right to regulate the diving environment - generally of course the law is passed by the Polish parliement but written by CMAS guys. So we do have a war between CMAS and PADI. Most of the CMAS instructors are doing everything to proof that PADI is worse and doesn't teach properly despite all the global agreements.
But anyway I'm living in a strange country...
Mania

Thanks for the info! Dive safe

 

[pipedope]

It looks like the Kp is the multiplier used to compensate for the highest PO2 during the dive. It is looked up in a table and increases with increasing max PO2 during the dive.
There is another table of average and total dose of OTUs that accounts for multiple days of diving.

The REPEX system was developed by Dr. Bill Hamilton, a diving physiologist. In normal use it is done with tables instead of the equations.

If a diver is stringing day after day together diving nitrox then tracking this is a good idea. On any single dive or diving day CNS O2 toxicity is going to be the limit first.