Post Hydro O2 re-cleaning?

[DA Aquamaster]

I agree with you Phil that there are a lot of accidents. It would be good though to actually see the data and more importantly to see the causes of the fires as I suspect most have nothing to do with tank or valve contamination.

I think if there were clear trends indicating that dirty tanks were the issue, rather than darwin award winning mixing of fire and O2, OSHA, DOT or some other agency would mandate a suitable O2 cleaning protocol.

My ex-wife used to have a person every week or two come into the pharmacy with burns from an O2 fire, but it was almost always the result of someone smoking on O2 or with the mask close by - and never to my knowledge because the tank or regulator was dirty.

Even with fuel and O2 present, you still need an ignition source. I can see tumbling the tank and cleaning valves and regs with blue/gold, simple green, etc. but cleaning them like they were about to be launched on the space shuttle is a bit much and realistically is not even valid after getting half way through the first fill.

There is obviously an appropriate middle gound somewhere and it seems to me that it would make more sense to focus on good operational techique along with cheap fast and readily available (ienly adequate rather than near perfect) cleaning as a means to keep contamination to low levels and prevent buildup over time.

 

[PhilEllis]

I agree with you Phil that there are a lot of accidents. It would be good though to actually see the data and more importantly to see the causes of the fires as I suspect most have nothing to do with tank or valve contamination.

I think if there were clear trends indicating that dirty tanks were the issue, rather than darwin award winning mixing of fire and O2, OSHA, DOT or some other agency would mandate a suitable O2 cleaning protocol.

My ex-wife used to have a person every week or two come into the pharmacy with burns from an O2 fire, but it was almost always the result of someone smoking on O2 or with the mask close by - and never to my knowledge because the tank or regulator was dirty.

Even with fuel and O2 present, you still need an ignition source. I can see tumbling the tank and cleaning valves and regs with blue/gold, simple green, etc. but cleaning them like they were about to be launched on the space shuttle is a bit much and realistically is not even valid after getting half way through the first fill.

There is obviously an appropriate middle gound somewhere and it seems to me that it would make more sense to focus on good operational techique along with cheap fast and readily available (ienly adequate rather than near perfect) cleaning as a means to keep contamination to low levels and prevent buildup over time.

Darn, I can't find the website I was looking for. It has been months, and my brain is old. One thing I do remember....there were literally hundreds of the aluminum oxygen regulators that had been implicated in fires; most completely melting the regulator and turning the whole assembly into a blow torch.

I will keep looking for the website. It was interesting reading.

Phil Ellis

 

[rjack321]

The welding and medical industries do have the benefit of using valves actually designed for O2 service. Not some kludge nylon seated, fast opening plug valve.

Honestly I doubt anything other than actual compressor oil in a tank might combust. And even that is remote with good filling practices. But a scuba valve on the other hand seems to not tolerate even minute quantities of oil, grease, or dirt.

I always keep my valves at home in a baggie. I would never trust the hydro shop to keep those even remotely clean. And they seem to be the critical piece in scuba service. I clean them, but why let anyone get it any dirtier?

 

[oxyhacker]

I always clean my tanks after hydro. Easy enough to do, and no way to know what may have gotten inside.

BTW, the hydrotest man at my gas supplier tells me that they don't routinely clean O2 tanks at hydro time, but clean them with TSP if they see any sign of contamination when they visually inspect them. And that they never reuse water when hydrotesting, but use fresh water for each tank.

But then they are using completely dedicated gear, unlike us, so the opportunities for contamination are much less.

 

[DA Aquamaster]

The welding and medical industries do have the benefit of using valves actually designed for O2 service. Not some kludge nylon seated, fast opening plug valve.

Honestly I doubt anything other than actual compressor oil in a tank might combust. And even that is remote with good filling practices. But a scuba valve on the other hand seems to not tolerate even minute quantities of oil, grease, or dirt.

I always keep my valves at home in a baggie. I would never trust the hydro shop to keep those even remotely clean. And they seem to be the critical piece in scuba service. I clean them, but why let anyone get it any dirtier?

I agree, unless you fill a tank fast, there just is not much opportunity for excessive heating to occur.

Valves on the other hand may have sharp corners and edges that can cause a hot spot and the interior spaces in them (and the high pressure areas of the regulator) are going from ambient to tank pressure potentially very quickly - especially with some of the valves sold today that go from off to on very quickly.

I agree that cleaning valves makes sense as does sound operating procedure to bring the pressure up slowly inside valves and regs as they potentially see rapid pressure and temperature spikes that tanks just won't see.

 

[rjack321]

BTW, the hydrotest man at my gas supplier tells me that they don't routinely clean O2 tanks at hydro time, but clean them with TSP if they see any sign of contamination when they visually inspect them. And that they never reuse water when hydrotesting, but use fresh water for each tank.

But then they are using completely dedicated gear, unlike us, so the opportunities for contamination are much less.

I would trust a gas supplier to keep tanks alot cleaner than my hydro tester. Afterall, mine is in the fire extinguisher business!!

 

[akdeepdiver]

As both a diver, and the fact that I run a Hydro test facility, this is the protocal that we use. As one poster states, yes, the water inside the jacket is recycled and stays in the water jacket. The primary reason for this is becase it stays at the same temperature as when the testing aparatus was given its daily calibration. By maintaining a steady temperature, you get the most accurate reading. If one constantly emptys and fills the jacket, the temperature fluxuations will give false readings. Even a 1 or 2 degree change can alter the readings after calibration, resulting in a possibly hazardous situation. If you really want to get a understanding of this, find a physisist because they can explane it a lot better than me. Ha Ha. But back to the post. There is always a possibility of a slight hydrocarbon contamination. Therefore, all shops that send me O2 cylinders and even Nitrox cylinders, have me O2 clean the cylinders after hydro. Yes it costs them a little more, but they would rather not do it. All O2 cleaning is done in accordance to DOT and CGA guidelines and is done AFTER the hydro. For the shops that do not want the O2 Cleaning, I have a document that they sign stating that the cylinders were hydroed but NOT cleaned and it was thier responsibility to clean it before refilling. But so far, no shops want to go to the trouble to do it themselves and just pay me to do it. All of my cylinders that are tested are sent back tot he shops/owners with paperwork documenting all cleaning and services done.

 

[DA Aquamaster]

I would trust a gas supplier to keep tanks alot cleaner than my hydro tester. Afterall, mine is in the fire extinguisher business!!

Ooooh...I love conspiracy theories.

 

[scubaskipper]

I think DA AQUAMASTER hit it on the head when he mentioned the lawyers issue. Now add the insurance companies. They will ALWAYS go by the most over the top rules, NOAA, NASA, CGA. Most rules relating to dive shops are mandated by CGA regs. You have to remember this is a self regulating industry. We have to have some set of regs. to go by or sooner or later Washington or the State gets involved. Anyone remember the issue with transporting pressurized cylinders? That could easily ended up with every shop or instructor that brings tanks to a dive site needing all kinds of DOT hoops to jump through.
I've seen tanks that were filthy inside, oil, metal filings, etc... These were right from the factory. All had stickers saying they were good to go for O2. Tanks usually don't go to hydro with valves. They sit around the hydro place for however long and you are right, not the cleanest places. They do the test, now you've added water to the mix. Open to the air for however long it takes them to get the tanks back to the shop. Tanks come back with all kinds of flash rust. They aren't inspected for cracking of any kind at the hydro place, we have to do that after they get back. We also have to acid wash and whip to remove flash rust. Clean out the acid wash and rinse repeatedly. Coat interior with rust inhibitor and install the valve that has been total taken apart, acid washed, neutralized, soaped, repeatedly rinsed, blown dry, proper lube and O2 compatable parts installed. Even with the rust inhibitor, you have no more than 10 minutes to get the valve on or the whole process has to be done over, the tank starts to flash rust again.
The whole thing takes way more time and effort than is worth the price you get for the job. I would much rather not have to ever o2 clean another tank or valve. Insurance company and lawyer say you better or else. They look for a reason to not pay the policy or drag you into a law suit. So the next time you get the big bill for O2 cleaning tanks and valves, don't complain to the shop, we don't want to do it. Complain to your lawyer and insurance agent. I would think a reasonable and prudent thing to do is O2 clean every 5 years with the hydro. This is based on good handling methods and dependable compressor maint. in the time period between hydros.

 

[charlesml3]

there were literally hundreds of the aluminum oxygen regulators that had been implicated in fires; most completely melting the regulator and turning the whole assembly into a blow torch.

What was the source of fuel here? Oxygen, even 100% won't burn on it's own. There has to be some kind of fuel there.

-Charles