C02 Bottles - testing, repair, dates, etc.

I just called a company locally that does the hydro testing. I learned a few things.

1. Hydro testing can only be done with the valve off, once the valve is replaced they can't do any testing on the bottle.
I think most bottles have the valves added after-market as I am fairly sure Catalina doesn't sell cylinders with valves. Simply replacing the valve will NOT alter the cylinder's ability to hold CO2 OR violate its integrity UNLESS you damage it (threads) in the process, in which case hydro testing would not be able to determine this new problem UNLESS you take off the valve and have it tested AGAIN. .. This causes a testing loop and a subsequent time vortex ... you hydro test the cylinder to make sure it can handle the air.. then put on the valve.. but you don't know if the application of the valve altered the cylinder's ability to hold air.. off with the valve for a retest... repeat to infinity.

Bottom line replacing the valve does not alter the cylinder's integrity, I would say if the valve is not leaking at the shoulder of the bottle then its working as intended.

2. I learned DOT does not require testing on bottles no more than 2.0 inches in outside diameter and less than 2 feet in length.
The code on my bottle says " DOT-SP7737-1800" which when you reference it that tells you that it is a 3E bottle. Then you reference that to DOT CFR-49, 180.209, table 1.. and you get no testing required for at least the 3.5oz bottles and maybe the 5oz bottles (From 180.209 - 1Any cylinder not exceeding 2 inches outside diameter and less than 2 feet in length is excepted from volumetric expansion test.)
Later on in 180.209 - 3E tells (once interpreted) that the small bottles don't require a pressure test either.

SP7737 see #2
http://www.phmsa.dot.gov/pv_obj_cac...A8C85DAB2F0100/filename/SP7737_2013081490.pdf

CFR-49
eCFR — Code of Federal Regulations


Please keep in mind this is not my opinion or personal interpretation of the DOT rules.. I consulted an expert in the field with over 20 years experience. My source is Roger @ Western Testing in Pasadena Texas.

I posted this because I mistakenly thought that if I replaced the valve myself I would have to send it in for testing but it wouldn't matter.. they take off the valve anyway. I also mistakenly believe the valve had something to do with the integrity of the cylinder.. which it doesn't in any way.

NOTE - the valve DOES affect the OVERALL Air SYSTEM integrity but that is something a hydro or pressure test is unable to evaluate.

I of course would not recommend anyone take the valve off unless they were mechanically experienced.

Thanks

Johnny

 

My 3.5oz bottle in question is 1.99 OD and of course less than 2 feet long. It has a date code of 7/08 so its beyond the 5 years that some folks talk about but per the DOT regulations .. has not expired.

I DO however plan to just let Western Testing do the testing on it and replace the valve o-ring for me for $20.

I have one other bottle that has a bad valve so I think I will buy a valve, put it on the bottle and take it in with the other to Western. It will still be cheaper than 60 bucks for a new bottle.

Thanks

Johnny

 

I've opened most of my bottles to install anti-siphon tubes. My only comment to the above is red Loctite when the valve goes back on and try not to plug the little bleed hole when doing so. To get on old valve off, heat works well to soften the Loctite up.

 

There probably is but I suspect my vise slips before getting to it. That brings up a good point though. Any physical damage to the outside of the bottle will invalidate it as far as a hydro goes. Damage like vice and vice-grip marks etc. Save that old leather belt that doesn't fit anymore for some padding when clamping a bottle. When clamping a bottle do it towards either end as that's the strongest sections. Clamping down in the middle can distort the bottle.

FYI, I wouldn't even think of replacing the valve on a fiber tank. I suspect a special clamping jig is required (if it could be done at all).

 

On all valves there is a O ring that is between the valve and bottle that does the sealing, the locktite only keeps you from unscrewing the valve from the bottle in error. Any galling or obvious mechanical damage to the bottle makes any rating void.

 

I will ask Roger about the torque spec when I drop off the bottles. I called him 3 times today without giving him business.... I don't want to bother him again.

 

Valve installation torque values for Luxfer aluminum alloy cylinders and liners - Luxfer: Setting The Standard Worldwide

50 ft-lbs max.

 

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