Poisonous Air in Divers Bottles - Hot Compressors

You should never breathe compressed air!!

There are filtering systems for this very purpose, but they are expensive of course...

All compressed air contains particulates and noxious gases, even from 'oil free' compressors.

Filters to make the compressed air breathable are complex and expensive using HEPA and activated charcoal as well as monitoring systems to filter and 'scrub' the air.

John.

Thanks for that, but hepa and charcoal filters are not good enough when compressors run hot. They saturate very quickly. Only when perfectly fresh (brand new elements) can charcoal remove toxic contaminants - but once 'wet' charcoal is only good for 'oily' smell. Removing the smell is not necessarily a good idea because if CO was present the smell of 'burning' oil would be a warning.

Scrubbers, or probably catalysts, are used to remove CO. But only for a short time because the moisture in the compressed air soon saturates the catalyst to stop it working. The air must be thoroughly dried first. The drying mechanism is usually a desiccant material, that itself rapidly saturates when the air is hot.

A monitoring system might be OK for CO for bottle filling, but sometimes divers are on the end of airlines (fed by surface compressors maybe sucking in engine exhaust) and in the event of an alarm (how will they know) they will be forced to breathe this contaminated air during their slow ascent to avoid the bends.

The use of filtering systems, albeit expensive, would be OK I suppose, but only if sized for the 'worst' conditions - rather than 'normal' running conditions. Where, to make it worse, 'normal' is assumed to be 'ideal' - which is far from reality.

Compressors run hot (they sometimes catch fire) - and just how hot is 'normal'?

Does anybody know of information on fatalities in this respect?

As I said the required filtering equipment necessary to make compressed air breathable is complex...

Please, Do not think its just a HEPA and charcoal filters!!

John.

DO NOT tell your life insurance co. that you are using compressors not designed to use for filling divers air bottles or hose to mask type equipment. You probably will suffer ,if lucky, lung/brain damage or death if unlucky.

The expression 'deadly serious' comes to mind here.

larger compressors (more than one bottle, slow charge types) are or should be water cooled.

Also, if you want to get the maximum mass of air in your tanks, keep them in cold water while being filled.

I was a US Navy qualified diver, my suggestion is that you buy borrow or swipe a copy of the US Navy Divers Manual. It is well worth the few bucks you pay for it and it will probably save your life from the sound of what you are panning to do.

I am a former deep sea diver with several certifications in dive medicine and many others over the last 20 years. Compressors that are used to fill breathing aparatus are typically ordered for that purpose and never, ever have hydrocarbon based lubes in them. Rather they use mineral oil which does not release C0 at temerature. It is quite safe. O-rings are to be sealed with "bouy butter" which is also a mineral oil based lube.

If you know of someone that is using a compressor that was purchased at lets say a Hardware store to fill breathing tanks of any sort you must appeal to them to get educated as to the danger of using these. These compressors are not manufactured for use as a dive compressor so they have hydrocarbon based oils in them from the factory. You cannot clean them good enough to ever use for diving.

The C0 problem you describe is a very real senario with a compressor that is not specially built, purchased and certified to fill air tanks.

Please go here and read what osha says. http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=19339

They best equipment is only as good as the man/woman behind it. You had better make sure the filler is very competent both in the filling and maintenace procedures. I had some friends almost lose a man in Mexico due to a mistake in filling the tanks with an inlet tube too close to an exhaust outlet. If the equipment looks questionable or the operator acts questionable I wouldn't dive. Better real safe than dead! Roy Blizzard

I am a former commercial diver who worked underwater construction in the gulf of mexico in the 80's. Our air was supplied by Quincy two stage compressors powered by Lister diesel engines. The red colored oil used in these compressors was called Monolec, and as previously stated, did not produce CO. The compressed air was cooled in an after-cooler and stored in a volume tank. The after cooler and the volume tank cooled the air and knocked out "most" of the moisture. The air was then filtered by a multi stage filter before being supplied the diver. In "dive school" our air filter consisted of : marbles, activated charchol, and ladies' sanitary napkins(clean ones of course) This "old navy diver design" worked quite well actually. As far as the exhaust, yes one must be mindful, more than once, while in the water, I got a whiff of the Lister's diesel smoke and alerted topside personell who would immediatly corrrect the problem by making sure the intake was upwind of the exhaust.

I once worked on a CO monitor that was used to detect the presence of CO in breathable air supply for a very dirty hooded environment.It had a catalytic element that responded when exposed to CO.To calibrate required a known concentration of CO gas, supplied in small canisters the size of a butane torch canister. The system was designed to sound an alarm if the CO rose above a cetain level.I am sure diver filling apparatus has even more sophisticated systems employed.I know that for very cold water diving(dry suit) the air must be totally dessicated to prevent freezing of the regualors, etc.Please do not trust your tanks to anyone that does not have the required, certified equipment and knowledge.

Quality problems do occur with compressed and synthetic breathing air. Only procure or use bottled breathing air from a qualified source. Your concerns are valid, even with all of the quality programs in place today fatalities occur. Adopting a standard from competent Navy and leveragering their experiences may help clear things up.

There's that word again... 'leveraging'.....

Its not in my dictionary... What's it mean...?

Lever was a word never intended to spelt or used like this!!

How do you 'leverage' something? and if you do what happens to that thing?

John..... must be getting old....

Where did you learn your english?

"Lever was a word never intended to spelt or used like this!!"

Do you think you should have stated " intendended to be"

People from all around the world use this and their english isn't perfect. Some could sure put forth more effort and some try very hard.

Be carefull of casting stones from a glass house.

I learned my English in England in the days when it was known as the 'Queen's English'...

Just because a number of people in a different country modify or 'invent' a new word does not make that word part of the international language of English.

Sorry, but I didn't understand the last bit of your post, perhaps you should use a dictionary and use some grammar more often?

It depends on the compression ratio and how much heat is removed while the compressor is operating. Go to any compressor that has been running for a while, if you want a first hand impression of how hot the compressed air is, just lightly touch the output line. You might have to remove the guard that is there to keep people from getting burned. They can get damned hot!

A diesel engine is a compressor with a compression ratio of 12:1 up to ~15:1. This produces enough heat to ignite diesel fuel (which probably has a lower flash point than the lubricant used in a typical compressor. Diesel engines are liquid or air cooled.

I have only worked with larger compressors used for divers or for filling air flasks. There should be NO OIL in the air delivered to a human or animal. As the pressure goes up, so does the poisionus nature of the oil/air mixture.

Two Medical Doctors who were Professional divers researching mixed gas(oxygen, plus helium or nitrogen, argon, or ....) were killed when one of their tanks exploded in a diving chamber. The cause of the explosion was traced to a new air filter had that used to replace a dirty (used) filter. The new filter had a trace of oil in it from contamination during the manufacturing process.

OIL (specially hydrocarbon based) IN COMPRESSED GASES CONTAINING (O₂) IS DANGERIOUS.

A scuba diver myself, I just read with horror about using female sanitary napkins as a filter medium, I lived in Malaysia for 3 years & did a fair bit of of diving over there, and to save money on the correct filtration medium this is what a lot of so called "dive shops" did in Malaysia , many of the new clean napkins contain various deoderants and perfumes which under the forces of compression become concentrated in the air being breathed and caused breathing problems for people breathing this air , I always had my cylinders filled by MOX with medical quality air.

Is your life not worth a few buck more to breathe high quality air ??

I am grateful to all those people with actual experience who have taken the trouble to answer my question. I am not worried about invented words or foreign words as long as the reply is in English, and as long as I can make sense of the message.

Generally, it seems as though most repliers are in agreement that compressors can deliver poisonous air if strict precautions are not taken.

There also seems to be an underlying reliance on 'certification' of quality standards, official guidance and air quality testing.

Unfortunately this is something left too much to chance because there is little policing of the regulations .

Guess who pays the price when things go wrong.

I will come back anon as my knowledge base increases, but in the meantime it would be helpful to find out how hot compressors can get - some actual Centigrade or Farenheit numbers would help.