Ask X3What does 49 CFR 173.304 (Filling of cylinders with liquefied compressed gases) require?
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As a motor-carrier owner, when filling and offering cylinders with liquefied compressed gases for transportation, you must follow these general requirements under 49 CFR 173.304:
* General Compliance: Except for certain gas-in-solution items and specific exceptions, cylinders filled with a liquefied compressed gas must meet the requirements of 49 CFR 173.304 and the general requirements in § 173.301. DOT specification cylinders must also meet §§ 173.301a, 173.304a, and 173.305, as applicable. UN pressure receptacles must comply with §§ 173.301b and 173.304b.
* DOT 3AL Cylinders: A DOT 3AL cylinder cannot be used for any material that has a primary or subsidiary hazard of Class 8.
* Division 2.1 Materials: Shipments of Division 2.1 materials in aluminum cylinders are only authorized when transported by motor vehicle, rail car, or cargo-only aircraft.
* Filling Limits: For most liquefied gases (except carbon dioxide; 1,1-Difluoroethylene (R-1132A); nitrous oxide; and inhibited vinyl fluoride), the liquid portion cannot completely fill the packaging at any temperature up to and including 55 °C (131 °F). For inhibited vinyl fluoride, the liquid may completely fill the cylinder at 55 °C (131 °F) only if the pressure at the critical temperature does not exceed 1.25 times the cylinder's service pressure.
* Gas Mixtures: Compressed gas mixtures must be shipped in accordance with § 173.305.
* Refrigerant and Dispersant Gases: Nontoxic and nonflammable refrigerant or dispersant gases must use cylinders prescribed in § 173.304a or DOT 2P, 2Q, or 2Q1 containers (with specific packaging, pressure limits, heating tests, and outer-package marking requirements).
* Engine Starting Fluid: Engine starting fluid containing flammable compressed gas must be shipped in cylinders prescribed in § 173.304a or in inside non-refillable metal containers meeting specific capacity, pressure, heat testing, and outer-packaging marking standards.
* Oxidizing Gases by Aircraft: Cylinders containing specific oxidizing gas mixtures or nitrous oxide intended for aircraft transport must meet strict specification, pressure relief device, outer packaging, thermal resistance, flame penetration, and marking/labeling requirements.