czervos
Registered
I plan to take the PADI Nitrox course soon, but bought the book ahead of time. I've run across a sample problem that I don't understand and hoped for some insight. Below is the question and the solution I arrived at:
A diver plans two dives. The first dive is planned to 87 feet using EANx36. Assuming the diver stays to the no decompression limit, followed by a 1 hour surface interval, what is the maximum allowable dive time for a repetitive dive to 48 feet using EANx40?
I found that the EAD of 87' is equal to 67' which the NDL is 40 min. This had a O2pp of 1.34 and 30% allowable oxygen exposure. This put the diver in pressure group T and after 60 min SI, entered pressure group G. Using EANx40 at 48', it would be equivalent to 30' using air and O2pp was 1.01. On the exposure table, I found that to use the remaining 70% allowable exposure, at O2pp of 1.1, the diver could stay 168 min.
The book says that the correct answer is 165 min. Any ideas?
A diver plans two dives. The first dive is planned to 87 feet using EANx36. Assuming the diver stays to the no decompression limit, followed by a 1 hour surface interval, what is the maximum allowable dive time for a repetitive dive to 48 feet using EANx40?
I found that the EAD of 87' is equal to 67' which the NDL is 40 min. This had a O2pp of 1.34 and 30% allowable oxygen exposure. This put the diver in pressure group T and after 60 min SI, entered pressure group G. Using EANx40 at 48', it would be equivalent to 30' using air and O2pp was 1.01. On the exposure table, I found that to use the remaining 70% allowable exposure, at O2pp of 1.1, the diver could stay 168 min.
The book says that the correct answer is 165 min. Any ideas?