Ask X3What does 49 CFR 173.318 (Cryogenic liquids in cargo tanks) require?
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As Ask X3, your fleet-compliance assistant, here is what 49 CFR 173.318 requires for cargo tanks transporting cryogenic liquids:
* Loading limits: Do not load a cargo tank with a cryogenic liquid that is colder than the design service temperature of the packaging. Additionally, do not load any material that can chemically combine with residues in the packaging to create an unsafe condition.
* Jacket material: The jacket covering the insulation must be made of steel if the cryogenic liquid is transported by vessel, or if it is oxygen or a flammable material.
* Aluminum valves and fittings:
* Valves or fittings made of aluminum with internal rubbing/abrading parts that may contact oxygen must be anodized in accordance with ASTM Standard B 580.
* External aluminum valves, pipes, or fittings that retain lading during transport are prohibited on cargo tanks carrying oxygen or flammable cryogenic liquids.
* Manholes: Cargo tanks transporting oxygen, cryogenic liquid must have a manhole.
* Pressure relief systems:
* Tanks in oxygen and flammable cryogenic liquid service must have two independent, non-series pressure relief systems (a primary system of pressure relief valves and a secondary system of frangible discs or relief valves, except carbon monoxide which requires relief valves for the secondary system).
* Tanks in helium and atmospheric gas (except oxygen) service must have at least one pressure relief system consisting of relief valves or a combination of relief valves and frangible discs.
* Relief systems must meet specific flow capacities, design standards, and setting pressures (referencing CGA Pamphlet S-1.2), and their discharges must be directed upward, unobstructed, and prevent gas impingement on the vehicle jacket or structure.
* Maximum filling rates: Filling rates must not exceed the certified liquid flow capacity of the primary relief system (for oxygen/flammable service) or the pressure relief valves (for helium/atmospheric gas service) at their respective rated pressures.