Couv,
My test only supported Luis for the surface pressures. The NEDU tests say that at 62.5 R/M/V (Respiratory Minute Volume, 31.5 respirations per minute of 2 liters per respiration, which is extremely heavy work), the Scubapro AIR I/Mk V will exceed the Navy standards of 0.14 work in kg-M/L at about 170 feet depth on the 5 port swivel. On the 4 port swivel, this standard is exceeded at about 132 feet depth (sea water).
If we look at the Mk 5, four port swivel with the adjustable second stage (1980 version), at 62.5 R/V/M, exceeds the Navy limit at only 33 feet depth. The Mk 5, five port and four port swivel exceeds the Navy limit at about 132 feet at 40 R/V/M; no difference at these rates.
So there is a difference if we think the NEDU did these tests correctly, but not one we are likely to be aware of as we don't dive in that manner. 32 breaths per minute is something that fin swimmers do in competition. Divers usually are below 20 breaths per minute, and I like to dive at about 12 breaths per minute (normal surface breathing rate). At a R/M/V of 40 (20 breaths per minute, with 2 liters per breath), the AIR 1/Mk 5 Four Port version exceeds the Navy limit at somewhere around 250 feet, and the 5 port version is still under the Navy limit at 300 feet. However, I do experiment with high respiratory rates in underwater swimming, as I am developing new underwater swimming techniques. Therefore, I keep my AIR 1 on the end port.
CaptainK, you probably will be pretty happy with your Mk 1. However, at one point or another, you may want the flexibility of the Mk 5. If so, get the 5-port model, and I think Couv has some of those available. I know this discussion has gotten pretty technical, but it interests some of us, so I hope it has helped you too.
SeaRat
My test only supported Luis for the surface pressures. The NEDU tests say that at 62.5 R/M/V (Respiratory Minute Volume, 31.5 respirations per minute of 2 liters per respiration, which is extremely heavy work), the Scubapro AIR I/Mk V will exceed the Navy standards of 0.14 work in kg-M/L at about 170 feet depth on the 5 port swivel. On the 4 port swivel, this standard is exceeded at about 132 feet depth (sea water).
If we look at the Mk 5, four port swivel with the adjustable second stage (1980 version), at 62.5 R/V/M, exceeds the Navy limit at only 33 feet depth. The Mk 5, five port and four port swivel exceeds the Navy limit at about 132 feet at 40 R/V/M; no difference at these rates.
So there is a difference if we think the NEDU did these tests correctly, but not one we are likely to be aware of as we don't dive in that manner. 32 breaths per minute is something that fin swimmers do in competition. Divers usually are below 20 breaths per minute, and I like to dive at about 12 breaths per minute (normal surface breathing rate). At a R/M/V of 40 (20 breaths per minute, with 2 liters per breath), the AIR 1/Mk 5 Four Port version exceeds the Navy limit at somewhere around 250 feet, and the 5 port version is still under the Navy limit at 300 feet. However, I do experiment with high respiratory rates in underwater swimming, as I am developing new underwater swimming techniques. Therefore, I keep my AIR 1 on the end port.
CaptainK, you probably will be pretty happy with your Mk 1. However, at one point or another, you may want the flexibility of the Mk 5. If so, get the 5-port model, and I think Couv has some of those available. I know this discussion has gotten pretty technical, but it interests some of us, so I hope it has helped you too.
SeaRat
