Ask X3What does 49 CFR 178.65 (Specification 39 non-reusable (non-refillable) cylinders) require?
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According to 49 CFR 178.65, a DOT 39 non-reusable cylinder is a seamless, welded, or brazed vessel where the service pressure cannot exceed 80 percent of the test pressure. To ensure compliance, motor-carrier owners must adhere to the following practical requirements:
* Size Limits:
* For a service pressure of 500 p.s.i.g. or less, the maximum water capacity cannot exceed 55 pounds (1,526 cubic inches).
* For a service pressure exceeding 500 p.s.i.g., the maximum water capacity cannot exceed 10 pounds (277 cubic inches).
* Aluminum is not authorized for service pressures over 500 p.s.i.g., and longitudinal or helical welded steel cylinders are also not authorized for service pressures above 500 p.s.i.g.
* Test Pressure: The minimum test pressure must be the maximum pressure of the contents at 130 °F or 180 p.s.i.g., whichever is greater.
* Materials and Manufacturing: Cylinders must be made of approved steel or aluminum, be free of defects like seams or cracks that weaken the structure, and have clean, dry interior surfaces free of loose particles. Welded procedures and operators must be qualified using CGA Pamphlet C-3.
* Openings and Attachments: Openings and attachments are permitted only on the heads, must fall within an imaginary circle not exceeding 80 percent of the cylinder's outside diameter, and must be reinforced unless the head is thick enough.
* Pressure and Leakage Testing: Every cylinder must undergo a proof pressure test and a leakage test (such as underwater submersion). Any cylinder that leaks, shows visible distortion, or has defects during testing must be rejected. Additionally, destructive burst tests and flattening tests must be performed on sample cylinders from each production lot, and the entire lot must be rejected if samples fail.