Can I Use This?
By Mark A. Gresham
In the month of May PSI-PCI received no less than 44 requests for information on reusing two types of cylinders for dry suit inflation. There have been several persons purporting erroneous information on the Web so let’s examine the types of cylinders that divers want to use.
The first type is an aluminum cylinder in an unmarked cylinder that is intended for use with a countertop appliance that carbonates liquids mimicking commercially produced soft drinks. This cylinder is produced by an offshore non-US company for the device itself and it not intended to be used for any other purpose than carbonating the liquid the user has chosen. There are those who erroneously assume pressures to these cylinders based on “it looks like” or “it is pressurized to XXX” or “hydro tested to XXX” so therefore it can be filled to XXX. This type of cylinder is not hydrostatically tested; they are only proof pressure tested at time of manufacture. They are intended to be used, recycled and NOT refilled. There are no markings on the cylinders anywhere. We contacted the manufacturer and they simply stated “they are one use cylinders”.
The second type of cylinder is a US DOT regulated Type 39 Non Refillable Container (NRC) also used to carbonate liquids at home. They are marked with 39 and NRC - usually on the bottom. We really do not know a better method to describe or articulate the words NON REFILLABLE!
The instructions described by the company that markets them suggests once the cylinder gas is expended you take them to one of their official retailers and along with money trade them in for a new cylinder. There are no provisions for the user to refill even though there are refill adapters sold. Just because you can doesn’t mean you should.
They are designed and built for one use, so they are constructed as cheaply as possible with thin sidewalls. They are not designed for multiple use and will incur permanent deformation (permanent damage) and potential rupture if repeatedly filled.
We strongly urge those who use or are contemplating using both types of cylinders discussed here reconsider. This practice is dangerous and foolhardy and illegal. In fact the Code of Federal Regulations (CFR) dictates that fines and imprisonment may occur for refilling them:
49 CFR 178.65(i)(A)
(A) For cylinders manufactured prior to October 1, 1996: “Federal law forbids transportation if refilled-penalty up to $25,000 fine and 5 years imprisonment (49 U.S.C. 1809)” or “Federal law forbids transportation if refilled-penalty up to $500,000 fine and 5 years imprisonment (49 U.S.C. 5124).”
(B) For cylinders manufactured on or after October 1, 1996: “Federal law forbids transportation if refilled-penalty up to $500,000 fine and 5 years imprisonment (49 U.S.C. 5124).”
Another important rule to remember is that a stamped or marked cylinder can only contain (or be filled) with the gas for which it is stamped or marked.
As you can see there are several important items to consider before potential injury or fines occur so please be thoughtful.
Questions or comments please contact the author at 425-398-4300 or