I think it is some confusion in linking ATR to NDL. Each of these is an independent limit on dive time, with the shortest controlling.
I choose my NDL by selecting a computer with an established algorithm (Buhlman, which is generally regarded as middle of the road) and using the "standard" conservatism setting. Thus, when I dive to the NDL, I am not "diving to the limit" or "pushing the edge" but am just diving the conservatism of my plan and getting the most out of that plan instead of cutting the dive short.
Similarly, when I do my ATR settings, I choose a reserve that experience suggests will be adequate for a fast emergency air sharing ascent with no stop. Thus, when I dive to the ATR, I am not "pushing the edge" either, but diving the conservatism of my gas plan.
These are two different things. I don't want to cut myself short on either, so I dive the limit of my pre-planned conservatism, but that is not the same as the "limit" of DCS (not an exact science of course) or OOG.
Usually, I run out of NDL before I run out of ATR (thank heavens big steels are available where I dive!). But, if the particular dive got me to ATR first, I would follow that. The shortest of the two is the limit on my dive time.
No "grenades" for this diver!
I choose my NDL by selecting a computer with an established algorithm (Buhlman, which is generally regarded as middle of the road) and using the "standard" conservatism setting. Thus, when I dive to the NDL, I am not "diving to the limit" or "pushing the edge" but am just diving the conservatism of my plan and getting the most out of that plan instead of cutting the dive short.
Similarly, when I do my ATR settings, I choose a reserve that experience suggests will be adequate for a fast emergency air sharing ascent with no stop. Thus, when I dive to the ATR, I am not "pushing the edge" either, but diving the conservatism of my gas plan.
These are two different things. I don't want to cut myself short on either, so I dive the limit of my pre-planned conservatism, but that is not the same as the "limit" of DCS (not an exact science of course) or OOG.
Usually, I run out of NDL before I run out of ATR (thank heavens big steels are available where I dive!). But, if the particular dive got me to ATR first, I would follow that. The shortest of the two is the limit on my dive time.
No "grenades" for this diver!