School of the boat for 15 October - moved (Breathing)

[JTheotonio]

I'm moving this quiz up.  We seem to get answers mixed with other answers.  Some of this has been answered but read the questions.  There is more here guys....

Breathing is something we take for granted.  It is however important.  Prolonged submergence in a WWII Fleet Submarine will cause the original air in the submarine to become vitiated by the 1) reduced level of O2 and 2) by the increased level of CO2. This quiz falls more in to emergencies.  However, part of the question is vitial to working in a damaged compartment.   buck2

So my question is multi-part.
1. What are the upper acceptable levels of CO2?
2. What is the lower acceptable level of O2?
3. You are using chemical absorbents to reduce CO2, but you also need to stay submerged longer, what are you two options to revitalize the atmosphere?
4. Describe the locations and use of the oxygen system.

Lance, as you know Miners (not minors) where know to use little birds in cages.  They took the birds down in the mines when working.  Birds would collapse before a miner did when methane levels went too high.

[Darrin]

Thanks John for moving the post, meant to do it last night but got too damned busy with other work to do it

[Ctwilley]

I’ll take the first two. This stuff is my specialty.

1. According to OSHA, the recommend allowable limit of CO2 for an 8 hour work day shouldn’t exceed 5,000 ppm (0.5% saturation). Although for infants and older folks, it’s a lot less.
As far as for short term exposure, NIOSH sets the limit is 30,000 ppm (3% saturation) but warns that any exposure at 4% saturation or higher is immediately dangerous.

2. OSHA sets the standard for minimum O2 level at 19.5% but doesn’t take into consideration the several factors that must be accounted for including elevation, temperature, barometric pressure, and the overall condition of the people involved.
For example, someone at 10,000 ft above sea level can begin to feel the effects of hypoxia even though there’s 20% oxygen saturation due to the fact that there isn’t enough pressure to force the oxygen cells through the wall of the lungs. Also, someone that smokes a half a pack a day, will feel the effects of hypoxia before a non-smoker due to the carbon monoxide being carried by the hemoglobin (red blood cells). The CO causes the O2 molecules to bond to the blood cells and won't let them go. The cells then just carry oxygen around and never deposite it anywhere. This is called Hypoxemic hypoxia.
And one who drinks alcoholic beverages regularly or has just had a drink will suffer from Histotoxic hypoxia before a healthy individual will. The quantity of oxygen reaching the cells is normal, but the cells are unable to effectively use the oxygen due to disabled oxidative phosphorylation enzymes.

Dude, my crew chief SI would be proud….

[JTheotonio]

And one who drinks alcoholic beverages regularly or has just had a drink will suffer from Histotoxic hypoxia before a healthy individual will. The quantity of oxygen reaching the cells is normal, but the cells are unable to effectively use the oxygen due to disabled oxidative phosphorylation enzymes.

So much for my supply of Pink Lady.  CT I will post the section to check after the rest of the question is answered.  But you get 100% on your answer for parts one and two.  The Navy was a bit simpler in how they taught us many years ago.

[Darrin]

Hey Lance please add JT to the list of moderator's for this part of the forum, he knows more about being a moderator then I do and he knows what he is talking about when it comes to the school of the boat forum

[Ctwilley]

I aced Aero-med in the Army. They feel the need to teach you everything there is to know about hypoxia and oxygen due to flight risks.

[Darrin]

All,
emeacho (aka Chief Mike) posted this earlier and he has been busier then hell so I am going to help him out and move his answer over from the previous school of the boat.

Posted by emeacho:

The oxygen system on a diesel boat of WWII was called "O2 cylinders".  They are placed in every compartment, usually hung in the overhead from brackets.  The nukes have O2 generators that supply O2 banks.  The banks can bleed inboard.

To remove CO2, the crew spread LiOH (lithium hydroxide) out on mattress covers and the chemical absorbed the CO2.  Watch it, the stuff got hot when it reacted with CO2.  The LiOH canisters were kind of oblong in the old days and after WWII they were round, gray cans.  They were hung from brackets in the overhead or from the side of the pressure hull on brackets in every compartment.  The torpedo rooms had hundreds of them, probably because these were the spaces where you would congregate in an escape attempt.  Torsk has a bunch of these canisters which we found on the Trout.  Razorback also has a bunch.  I know Pampanito reproduced a bunch of the WWII type.

The nukes now adays use CO2 scrubbers and CO/H2 burners to remove unwanted gas.  In an emergency, the bunk curtains are CO2 absorbant.

[Darrin]

Corey,
just wait until you hear some of the stories from those who rode the boats and the air quality was less then stellar

[JTheotonio]

Old TM buddy - Chief Mike got part of the question.  But everyone look at the question - you have your CO2 absorbent spread out - so what are the two other things that you need to do that will help revitalize the atmosphere.  Yes we could do a couple of other things and they are in the manual folks.  Dig! 

[Darrin]

I know that my fellow TM, I was trying to further their digging so we wouldn't have the same answer posted already and like JT said DIG! you can find it

[JTheotonio]

OK, looks like no one wants to dig up the remaining answers to the last question.  So here are some facts.

CO2 limits should be kept below 3%.  1% or less is harmless and after air purification is started, you should try to keep the level at or below 1%.  During the last few hours of submergence, you were allowed to let CO2 rise to about 3%.
2% may not be noticeable, but may show discomfort when doing strenuous work
Breathing when prolonged level of 3% may cause discomfort even when resting.
4% and above is dangerous and you should reduce levels as fast as possible.
Oxygen should not be allowed to get below 17%.

Here is the final part of what I was looking for...

Beside chemical CO2 absorbent, what can be done to revitalize air?
After starting chemical CO2 absorbent you should also bleed into the boat 0.9 CU FT of oxygen, at atmospheric pressure, per man hour.

In lieu of oxygen, you can bleed air from the compressed air tanks at a rate of 31 CU FT per man hour.

You can start the high pressure air compressor and pump a slight vacuum in the boat, charging this air into a LP air bank, then bleed air into the boat from a HP air bank that was charged while the boat was surfaced.

If possible, always thoroughly vent the boat before submerging.

[Lance Dean]

And from what I've been reading over on a different BBS, the record for the WWII diesels subs was around 30 hours submerged?  That must suck.

[JTheotonio]

30 hours seems a stretch.  I do know a WWII guy who was on the USS GUAVINA SS362.  It was their 4th patrol of the war that had them pinned down for more than 20 hours.  Some said 24 hours, while some, including him, said they thought it to be more like 27 hours.  However, since no one seemed to agree, his account, reflects only that it was over 20 hours.

Like folklore, stories get embellished as they are repeated over and over.  I don't disagree that someone could have been pinned down for 30 hours.  But it would have been hell, lots of luck and good work on keeping CO2 levels low enough not to kill anyone.  I'd sure like to see the war patrol report for this one.

This brings up interesting bit of information.  The H. L. Hunley often thought to have gone down due to damage, may have been due to suffocation of the crew.  This last week or so the scientists working on the Hunley found that the pump system was not in the position that it needed to be to pump out water.  So they believe that the Hunley did not sink from damage and flooding as often thought.  Eight men died on the Hunley.  The boat is only 40 foot long so eight men would have consumed a lot of the air.  The Hunley had to wait a considerable bit of time before it attacked and sank the 1240-ton steam sloop USS Housatonic in Charleston harbor.

I'm sure we will learn more as further tests are done.