Mailing List Archive Mailing List Archive
Michael J. Black writes: > Ben Wiseley wrote: > > I read somewhere that you needed the narcotic properties of nitrogen > > to off-set some effect of helium... (snip) But for recreational divers > > would heliox be preferred (assuming money was no object)? In other > > words... if money didn't matter at all would diving to 60 feet on > > heliox be safer than air? > > The disadvantages of helium include increased conductive heat loss, Not true. Helium is indeed more conductive than nitrogen, which is why it should not be used as a suit gas. However, conductive heat loss through the lungs is actually less with helium, as the heat capacity of helium is lower than nitrogen. In fact, a given volume of HE will absorb about 70% of the heat than an equivalent volume of N2, so net effect is that HE mixes may feel cooler, but in fact bleed off less heat than nitrogen mixes. Cp (HE) -- 20.786 Joules / Kelvin Mole Cp (N2) -- 29.12 Joules / Kelvin Mole CAVEAT: While I've done the math, I've never actually done a mix dive. Yet. :) Brian. (Armchair diving at it's best.) -- grnbrg@cc*.um*.ca* -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]