That's an old study that has been refuted. There is a new study (Hobbs, Rubicon I think. I'll go looking for it later when I time. EDIT: found it. See next post below) that says that there IS an advantage to argon.
Well...not really. From the abstract (
bold added):
"Prior to manikin submergence,
the drysuits were repeatedly inflated and then purged with either air or industrial grade argon for a minimum of 6 cycles to insure the purity of the inflation gas inside the drysuit. RESULTS: Improvements in localized thermal insulation values were seen throughout both drysuit ensembles when using argon as an inflation gas when compared with those while using air. Overall,
the total suit insulation values increased by 16 20% for the two drysuit ensembles. CONCLUSIONS: This investigation has demonstrated that significant improvements in drysuit thermal protection can theoretically be achieved when using argon instead of air as a drysuit inflation gas.
It should be noted however that these improvements can only be achieved by carefully and repeatedly purging (a minimum of 6 purge cycles) with pure argon prior to water entry. (Note: http://archive.rubicon-foundation.org/7962)"
In short it says what divers who have used argon and compared it to air and been honest about it have always said - it is a great theory offerring a small theoretical increase in warmth but it is not practical in the field.
Similarly, the "refuted" study and this one do not disagree. The earlier study flushed the suit 3 times rather than 6 times and found no significant increase in warmth. The later study flushed the suit 6 times and found an increase of only 16-20% and clearly notes you'd need to flush the suit a
minimum of 6 times.
So in effect, argon may give a slight increase but you'd have to completely flush the suit at least 6 times to get a fairly small (1/6 to 1/5) increase in efficiency. If you are going to flush a minimum of 6 times (to the point where the dump valve activates), you better bring a large bottle of Argon as 6 or even 13 cu ft is not going to cut it.
Again, as I stated earlier and as Jeff G states, an inflation bottle is not needed unless you are diving trimix.
