Flying after teaching in pool

[resnick]

I'll be assisting with an evening PADI Open Water class next month that ends at 10pm. I'll be at a maximum of 12ft. At least once, I'm going to have to fly on business the following morning. Understanding that the general rule is "12 hours before flying", what are the real risks here? It seems like I should be at significantly less risk than if I did a day of diving in 100ft. So, is a 6am flight just nuts?

 

[Charlie99]

It should not pose a problem. As you note, the "12 hours before flying" rule is a simplistic rule that ignores both time and depth of the dive.

The NOAA Ascent after Diving tables http://www.ndc.noaa.gov/pdfs/AscentToAltitudeTable.pdf give the required surface interval time before making ascents to various altitudes. Use the 8,000' column for flying since the FAA limit on maximum cabin altitude is 8,000'. The Repetitive Groups are per the USN table --- http://www.ndc.noaa.gov/pdfs/NoDecoAirDiveTable.pdf.

By using those tables you can confirm what common sense tells you. More specifically, your minimum SI time before ascending to 8,000' is 3 hr 35 min after a dive 160 minutes long at 15'.

 

[Missdirected]

Nah you're fine. You will not have absorbed enough nitrogen at that depth to have a need to offgas.

Personally, after 33ft or so is when I'd wait the 24 hrs. Above that, no worries.

 

[Craig Clark]

How much time are you actually spending at 12 feet and for how long? Most classes do their assigned exercises then surface and go over the next skill and so on. Time at depth is usually a small amount of time and at 12 feet your nitrogen aborbtion is so little that it is not even worth worrying about.

 

[Dr Deco]

Hello resnick:

That depth for the short durations involved plus the length of time between the exposure plus the time of takeoff should give you a good safety margin.

Dr Deco :doctor: