Driving over mountains after diving?

[DandyDon]

It looks like a boring 6 hour drive. I'd be afraid of falling asleep on the road but driving bores me more than most.

I best this has come up a lot among other Phoenix divers. I wonder what replies he'd get in his home forum.

 

[krispykritter]

My computer has a 24hr countdown to fly, so not much help. It is a boring drive, I make my wife drive, and if I do take a hit on the mountain I wont kill my family.

 

[Abaco24]

I'd say after some psi relief from the GF or better half in bed or car, a steak or nice panini in the car, nice cobia or dolphin filet that you grilled prior to leaving and a nap cause she's driving for once.....then wake up, hit the head and hers, have a shaken but not stirred chilled glass in the cooler for the road ahead with the better half driving again and not bitchin at you since you made her happy, and you're all set.....head out and no worries, and have them clean the gear at home. Just a thought... But I digress..... plenty of "gas off" time

 

[DuboisP]

View attachment buhlmann.pdf
Look at Bulhmann (swiss physician) tables.

in the attached file, numbers are in metric, but you know how to convert in imperial
as for other tables, you have an "exit letter" -> residual group.

the interesting table is the last "passage d'un col et vol sans cabine pressurisée" -> "mountain pass and not pressurized plane"
1. no climbing during the first hour
2. after this first hour, climb regularly
3. you have to do all the calculated time to get at the height

assuming you have a 7500 ft mountain, a residual group of E and a end dive time at 1:00 pm
wait until 2:00 pm (you have to shower, load the car, drink some water, speak with friends...)
you can be at this 7500 fr mountain pass at 3:00 pm, regularly

for a 12 000 ft moutain pass
wait until 2:00 pm (1 hour)
7 500 ft at 3:00 pm (1 hour)
9 000 ft at 4:00 pm (1 hour)
10 500 ft at 5:00 pm (1 hour)
12 000 ft at 6:30 pm (1 hour and 30 min)

your 4500 ft mountain is not in the table :cool2:

 

[Rudebob]

Airplanes are pressurized to about 5000 feet above sea level, so driving to that altitude it is prudent to follow the safety suggestions for flying after diving. For lower altitudes, a lesser time is ok. Also, number of hours under water is an important factor. Be more cautious after repetitive dives over several days. I think you were right to be cautious. I would call DAN for their input. I am sure they have a chart of suggested intervals.
DivemasterDennis

The pressurization equivalent on commercial aircraft, vary somewhat significantly. Some Boeing aircraft are pressurized to nearly 7000 feet while some new airbus are closer to 5000 feet (the Bombardier commuter planes are even lower at 4500 feet). With nearly a 2500 foot swing between different aircraft precise modeling becomes a crap shoot. I guess that is why most computers simply have an 18 or 24 hour recommendation with a large safety margin built in.

As far as the original OP's question, I too live in the same city and have made the same trip. As already mentioned, between the time of the post dive boat ride, cleanup, shooting the bull, grabbing fuel, something to eat and then a 2 hour drive to get to the altitude mentioned, there is probably 4 hours + between the last dive and reaching the max altitude (which is a very short duration I might add). I and my dive buddies have done so without any ill affects several times-however, your mileage (or physiology) may vary.

 

[boulderjohn]

You might find this short article by Dr. Edmund Kay helpful. His recommendations are independent of particular agencies, tables, and residual/repetitive group notions. When I wrote the Altitude Diving specialty course for SSI, I factored in his recommended SIs. It's very handy around here when traversing high mountain passes after diving. Around here I use a rough guideline of two hours SI per 1000 feet elevation while driving.

I noted that the copyright on that material is dated 2000, which is before DAN completed its study that changed its 24 hour no fly recommendation to 18 hours. I assume that if the page had been updated to take that report into account, that would have been noted in a new copyright date.

---------- Post added ----------

The NOAA ascent to altitude table might come in handy. Just remember that the letters for the pressure groups probably don't match the ones you are using. That means that most divers can only really use it as a rough guide. This table is also pretty old by now.

 

[dpaustex]

There are high-altitude tables (as pointed out by others, which can be used for overall guidance).

Since most planes are pressurized to 5000-8000 feet, I'd personally following the full 18 hour rule. Note, that rule is NOT hard and fast, either (May? Issue of Scuba, Lessons for life, has article on guy with DCS 30 hours after diving).

 

[Edward3c]

BSAC have tables for altitude 0 to 3000m that contain a conversion chart for moving between the different levels.

Using 1000 millibars: Sea level = Level 1, 4500ft (1372m) = Level 3.

Providing your dives were within the 88 Tables, that includes all decompression stops - which from your discription they could be. Then anything after 4 hours is a surface code B/1.

Moving to Level 3 changes the surface code to D/3.

If you returned straight away to sea level the surface code would be C/1.

HTH

Regards

 

[IrishPaul]

If you are very concerned, you could drive north on the I15 from SD and get onto I-10 to PHX.

It would add an hour to your journey, but you avoid high altitudes.

 

[Thalassamania]

I live in phoenix and travil to San Diego to dive. On the drive home there is mountain that is about 4500 ft. This past weekend i dove 3 deep wreck dives, between 95 and 68 ft. We ended up going a different way home with less elivation change. How long before it is safe to drive over?

That's not as simple a question as it seems.

Airplanes are pressurized to about 5000 feet above sea level, so driving to that altitude it is prudent to follow the safety suggestions for flying after diving. For lower altitudes, a lesser time is ok. Also, number of hours under water is an important factor. Be more cautious after repetitive dives over several days. I think you were right to be cautious. I would call DAN for their input. I am sure they have a chart of suggested intervals.
DivemasterDennis

Most airliners are pressurized to 8,000 feet, not 5,000 feet. There is no single chart for intervals because the required interval varies with the time and depth of the exposure.

Diving in Fiordland NZ we faced a similar problem with driving over a mountain pass at 3000ft. This was a few years ago so I can't remember the exact amount of time to wait but it was something like 4 hrs. The operator had contacted DAN for information on how long to wait before going to elevation.

I believe the current recommendation is that it is OK to ascend to 2,000 feet following a no-D, non-repetitive dive.

How long after your last dive until you make the climb out of SD? I typically have around four to five hours from my last dive until we start the ascent to Las Vegas and have never had issues.
You could always plan your dives as though you are at altitude.

Planning as though it where an altitude dive is a good approach.

The NOAA ascent to altitude table might come in handy. Just remember that the letters for the pressure groups probably don't match the ones you are using. That means that most divers can only really use it as a rough guide. This table is also pretty old by now.

It's an oldie but a goodie, time tested. What I've done for the last 50, or so, years is to use the now very old U.S. Navy approach of assuring that I am in U.S.N. Group C or less before ascending to 8,000 feet. It has served me well on many occasions ... your results may vary.