Can I visit 5000' mountains after diving?

[jpdonvito]

Here in So. Cal, I can drive from sea level to our mountain cabin (about 5200 feet) in about two hours.

After diving, must I allow as much time for outgassiing as I would if flying in an airplane?

Thanks for your help.
Jayne

 

[david.tolan]

__AS FAR AS I KNOW__, cabin pressure in a commercial aircraft is equivalent to 8000 ft above sea level. It's cheaper than pressurising to sea level.

That would suggest that 5200 ft in the mountains is a respectable proportion of the effective altitude that you experience in a plane. In the absence of better information I'd be very inclined to wait the time to fly on the computer.

Err on the side of caution. If you suffer from DCS in a mountain cabin, help may be a long way away.

Blue Skies,
Soft landings,

Dave.

 

[DocVikingo]

including NOAA, USN, USAF, DAN, DCIEM & UHMS.

Not surprisingly, many differ, sometimes substantially.

Here's the rules of thumb that I use:

"Max Alt: Min Delay, Sngl, Low Stress Dive; Min Delay, Multi/Deco Dives

1000': None; None(low stress); 6 hr(mod stress)

2000': None; 2 hr(low stress); 8 hr(mod stress)

4000': 8 hr; 12 hr

6000': 12 hr; 24 hr

Table Definitions:

Low Stress: A dive performed well within the no-decompression limits, without significant risks such as high exertion, extremes of temperature, extreme fatigue etc.
Moderate Stress: Any dive performed to the no-decompression limit, decompression diving or dives involving one of the known risk factors for DCS.
High Stress: Extreme dive profiles, missed decompression stops or multiple risk factors. High Stress = High Risk. No predictions are possible due to the inherent alterations in off-gassing.

Slightly more complicated but in general in agreement with the table that I provided are the NOAA standards for Ascent to Altitude After Diving http://www.ndc.noaa.gov/dp_forms.html

Hope you find this helpful.

DocVikingo

 

[Dr Deco]

Dear jpdonvito:

Altitude

DocVikingo has some good (and quantitative) guidelines. One must always remember that divers will be moving about when they reach the mountain site. The waiting periods for airline passengers applies to individuals that will primarily be seated for the whole of the hypobaric (altitude) exposure.

Because of physical activity, such as walking around at altitude on the mountain, the risk is DCS in the legs increases. This is EXACTLY what we have found in our NASA test series comparing walking individuals and non-walking (as in zero gravity) individuals.

Dr Deco :doctor:

 

[Arnaud]

You should be careful. I dive in the Nothern part of Spain, on the Mediterranean side. When leaving this part of Spain, most people drive back through the French-Spanish border in Le Perthus. That's in the Pyrenean mountains.

While the border is at an altitude of only at 290 m/ 950 feet, there has been several cases of divers getting sick. As a result, most LDS recommend not to dive the same day you're going to be on the road. Obviously, I don't think the sickness they experience justifies a trip to a deco chamber. But still.

It all depends on the amount of diving you've been doing before hitting the road. The more you dive over a limited period of time, the more residual nitro is accumulated in the body.

As a safe rule of thumbs, my instructors have always advised to stick to the no flying recommendations (12 to 24 hours), or the computer calculations.

Why take any chance?

 

[jpdonvito]

Thanks, everyone, for replying so quickly to my question.

I can see that this is a serious matter and will definitely err on the side of caution.

My first dive, last week, was very tame: 22 feet for 31 minutes. But as time goes by, I'll be doing more adventurous dives.

I found the mention of exertion at altitude interesting, as I would have thought that more exertion would speed outgassing due to more oxygen being processed in the body. You're certainly right that dealing with an emergency in the mountains would be more difficult. I'll keep that in mind, too.

Jayne DonVito

 

[Dr Deco]

Dear Jayne:

Exertion

In this case, I was thinking of fairly heavy exertion. In this category, I would place climbing stairs, running, carrying equipment. :lifter:
Simply walking around is fine as it will improve blood flow and assist off gassing. :walking:

Dr Deco :doctor:

 

[jpdonvito]

Hmm, our cabin DOES have 52 steps to the main floor, not that I have ever jogged up all of them at once!

At the NOAA site, I found the chart called Required Surface Interval Before Ascent to Altitude After Diving.

The dive I plan for tomorrow will be less than 40 feet for less than 50 minutes, so I'll emerge an F diver. According to the chart, an F diver should wait 1 hour 12 minutes before ascending 5000 feet, or 3:40 before going up 6000 feet. Since our cabin is at 5120, it seems that using the 6000 foot time would leave me a good margin of safety.

According to the NOAA dive table, I should be a nearly down to a B diver by then. Does that sound good to go?

Thanks for your help.
Jayne

 

[DocVikingo]

Yes, the NOAA site I hot linked for you was specifically for the chart called "Required Surface Interval Before Ascent to Altitude After Diving." It does link directly or I would have done so.

You are correct. By the time you are a B diver, the NOAA chart indicates you are well in the clear to ascend to your cabin's altitude.

Best regards.

DocVikingo

 

[jpdonvito]

Dear DocV,

Thanks for confirming what I thought I understood from the NOAA table. I also talked to my instructor and he said the same thing: that with the novice dives my class will be doing, there is no cause for concern.

But I certainly appreciate your input and will keep all admonitions in mind when I become more advanced.

Jayne

PS The whole subject became moot this past weekend as our coastal storms made conditions so unfavorable that our class went kayaking in a sheltered harbor instead of diving. Hope next weekend finds us back in the water! ;-)