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During a recent exchange regarding IANTD, two minor comments were made in reference to American Nitrox Divers International (ANDI). These comments were isolated from the long exchange and both technically incorrect and personally disparaging responses were posted by two participants. On behalf of ANDI International I want to correct the technical errors associated with our standards. > 1.6 ATA is fine for a swimming dive I'm not exactly sure what this is intended to mean, but ANDI does teach that 1.6 ATA is the MAXIMUM recommended or suggested PO2 exposure. Page 37 of The Application of Enriched Air Mixtures, the textbook for ANDI's Complete SafeAirR User program describes the ranges of differing levels of oxygen dosage: 1.40 - Maximum dosage for extreme workload dives. Paul Bert effect becomes more likely above this value 1.45 - Begins the caution zone for normal exposures and the limit for high workload dives with regard to CNS toxicity - Paul Bert effect 1.60 - Maximum dosage for normal dives or "open-water" decompression only 45 minutes single dive exposure as the limit 1.60+ - CNS toxicity becomes a very likely occurrence - Paul Bert effect. Dosages in this range are very dependent upon time and CO2 loading 2.0 - 100% oxygen at two ATA (optimize out gassing of nitrogen) For "at rest" only situations - Hyperbaric therapy. --------------------------------------- ANDI certainly does not stand alone regarding the 1.6 limit, by the way. IANTD and TDI recognize the same limit and the same reasoning in their standards. In fact the 1.6 limit is based on the U.S. Navy, NOAA and DCIEM. From the ANDI Instructors Manual: Page 42: The U.S. Navy and NOAA: The U.S. Navy and the other large commercial diving enterprises backed the exposure limit of oxygen down to 1.6 ATA partial pressure. Page 44: ... U.S. Navy Manual - 1973 Table 9-20 - maximum oxygen partial pressure 1.6 ata for 30 minutes (April 1, 1990 changed to 1.6 ata for 45 minutes) - See ANDI CHART 2 - 4 NOAA Diving Manual table 11-1 (NOAA 1973 11-2 & US NAVY 1973 11-1) ANDI - CHART 2 - 4 -------------------------------------------------- Just as No Decompression Limits are maximum, not to be exceeded limits, 1.6 ATA is a maximum limit used in dive planning. One incorporates the realities of the caution zone, the unpredictability of an individual's response to oxygen's pathophysiology and employs variations such as cold, workload, extended decompression time, etc. into the dive plan. Dive planning is not done in a vacuum or with blinders on. Page 43: Carbon dioxide is the prime catalyst for CNS type oxygen toxicity. It is imperative to realize that high workload dives must be accompanied with more conservative dosages of oxygen. Page 47: Once again, ANDI wishes to stress that the probability of CNS toxicity occurring is very high if the exposure limits are exceeded during a high workload dive. There are no safety margins factored in. These are the real numbers. There are variables however. The variables are due to the extremely complex nature of oxygen's pathophysiology. Higher workloads mean higher CO2 production. As we have previously discussed, CO2 is the prime catalyst for inducing CNS toxicity reactions. Therefore if we plan higher workload dives or encounter conditions that cause extended respiration elevation we should not be operating at the maximum exposure limits. Back-off on the partial pressure or the time of exposure or both. ANDI recommends that the PO2 not exceed 1.45 ATA during these higher CO2 generating dives. ---------------------------------------------------- > it's "ok" to pack a 50/50 bottle for bailout from 130 FSW This is simply not the case and ANDI does NOT teach it. The comment seems to come from someone who has not even read an ANDI text or instructor's manual. From page 48 of the text: It is necessary to expand further on the of use of ponys and the concept of bailout gas and bottom gas. A bottom gas is a gas breathable at its maximum operating depth which limits the PO2 to 1.6 ata. A bailout gas is a gas breathed during emergency ascent. It is not acceptable for horizontal escape (ie. cave or wreck penetration.) It is recommended that the PO2 contained in a bailout gas should never exceed 2.0 ata PO2 (SafeAirC 50 as a bailout gas has a maximum operational depth limit of 100 FSW (30 MSW.) Application 7 from the Instructor's manual: For horizontal escape from an overhead environment do not exceed 1.6 ata PO2 dosage. For vertical ascents in MOD based upon 2.0 ata may be used as the gas would be breathed for extremely brief exposures. --------------------------------------------------------------- And again, the 1.6 and 2.0 referred to above are maximum limits. If you can find a reference to support your comment, please do so. > This guy's teaching practices ..... These are not "Ed Betts's standards" or teaching practices. These are ANDI's published standards. No one in the ANDI organization singlehandedly sets teaching policy or creates diving standards. -------------------------------------------------------- >I personally know ANDI (..) instructors that were given Instructor ratings in technical diving, and never made a technical dive!!! As I am the individual responsible for administering ANDI's quality control program, I would appreciate it if you would let me know as soon as possible who these people are, who taught them, when, and where. I can verify your information quickly and take the necessary action. With regard to the issue of experience at the diver level, to expect anyone to be fully competent and experienced at the end of any training program in any field is folly. That is not the purpose or function of a training program. How much experience did you have on the day you were certified as an open water diver, then as a nitrox diver, instructor, tech instructor, etc? How does that experience compare with your competence today? On the other hand, do you feel an agency should compromise its standards and "bless" an individual to the IT level simply because he feels he's experienced and it's his due? Or should he be asked to meet all the existing conditions and requirements of the position and actually demonstrate his competency to his peers? There seems to be a difference of opinion here. ---------------------------------------------------- A personal observation to the two individuals who made the remarks: George stated he was an ANDI certified diver, but he didn't say he was only ANDI certified. In his multipage posting, you chose to zero in only on a side comment regarding ANDI. You could have been a little more forthright and mentioned that you are both certified ANDI instructors. The rest of the people on the network can now more accurately judge your grasp of the topics you are discussing. As ANDI instructors, shouldn't you know your material better? ------------------------------------- A final comment. I suggest each of us be very careful about our postings. Making publicly libelous or slanderous statements about individuals or organizations might find one the subject of legal or other actions as those targeted protect their rights and reputations. -------------------------------------------------- Stuart Masch, Chief Operating Officer American Nitrox Divers International
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