Ask X3What does 49 CFR 173.302c (Additional requirements for the shipment of adsorbed gases in UN pressure receptacles) require?
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As Ask X3, your fleet-compliance assistant, here are the practical requirements for shipping adsorbed gases in UN pressure receptacles based on 49 CFR 173.302c:
* General Compliance: Cylinders filled with an adsorbed gas must meet the general requirements in 49 CFR 173.302, 173.301, and 173.301b, along with the specific rules in 49 CFR 173.302c.
* Pressure Limits:
* The pressure of each filled cylinder must be less than 101.3 kPa at 20 °C (68 °F) and no more than 300 kPa at 50 °C (122 °F).
* The minimum test pressure must be 21 bar, and the minimum burst pressure must be 94.5 bar.
* The internal pressure at 65 °C (149 °F) must not exceed the cylinder's test pressure.
* Adsorbent Material Requirements:
* Must be compatible with the cylinder, must not form harmful or dangerous compounds with the gas, and must not weaken the cylinder or cause dangerous reactions (like a catalyzing reaction).
* The quality of the adsorbent must be verified at every fill to ensure pressure and chemical stability.
* The adsorbent material must not meet the definition of any other hazard class.
* Requirements for Toxic Gases (LC50 $\le$ 200 ml/m³):
* Valve outlets must have pressure-retaining, gas-tight plugs or caps with matching threads.
* Valves must be packless with a non-perforated diaphragm or built to prevent leakage past the packing.
* Every cylinder and closure must be leakage-tested after filling.
* Valves must withstand the cylinder's test pressure and connect directly via taper-thread or ISO 10692-2-compliant means.
* Cylinders and valves must not be fitted with a pressure relief device.
* Pyrophoric Gases: Valve outlets must be fitted with gas-tight plugs or caps that have matching threads.
* Filling Procedures: Must follow Annex A of ISO 11513:2019 (note that ISO 11513:2011(E) is allowed until December 31, 2026).
* Requalification: The maximum period for periodic requalification must follow 49 CFR 180.207(c).