Nonrefillable cylinders

TC/DOT 39, These are nonrefillable (singletrip) cylinders made of seamless, welded or brazed steel or aluminum with a maximum volumetric capacity of 55 lb (25 kg) of water and a maximum service pressure of 500 psig (3450 kPa). Cylinders with maximum volumetric capacity of 10 lb (4.54 kg) of water can be produced for service pressures over 500 psig (3450 kPa). 

Nonrefillable containers such as those made to DOT or TC specifications 39, 2P, 2Q, 39M, 40, and 41 are considered by DOT and TC regulations to be unserviceable after one use, and therefore must not be refilled or reused for any purpose. Disposal of such cylinders should be in accordance with recommendations obtained from the suppliers who initially filled the cylinders. Such recommendations may sometimes be included in the labeling on the cylinders. 

It frequently will be necessary for the user to arrange the safe disposal of a compressed gas cylinder. With most types, disposal will be required because of the discovery of a leak or some other flaw. Certain types, moreover, are officially nonrefillable (e.g., DOT 39, 40, and 41). For such cylinders, the... 

Under present regulations, cylinders authorized for liquefied carbon dioxide service including fire extinguishers must be requalified by hydrostatic retest every five years, with three exceptions 3HT cylinders must be requalified by retest every three years no periodic retest is required for 3E cylinders and specification 39 cylinders are nonreuseable and nonrefillable. 

C-11 Recommended Practices for Inspection of Compressed Gas Cylinders at Time of Manufacture, Outlines U.S. DOT inspection requirements for cylinders as interpreted and practiced by manufacturers and inspectors. Qualification of certifying inspectors is covered as well as inspection requirements for seamless, welded, and brazed and nonrefillable cylinders. (20 pages)... 

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