{"operation":"document","citation":"49 CFR 180.203","title":"Definitions.","source_type":"regulation","agency":"Pipeline and Hazardous Materials Safety Administration","status":"current","official":true,"published_on":null,"effective_on":"2026-08-18","summary":"As used in this section, the word “cylinder” includes UN pressure receptacles. In addition to the definitions contained in § 171.8 of this subchapter, the following definitions apply to this subpart:\n\nCommercially free of corrosive components means a hazardous material having a moisture content less","machine_formats":{"json":"https://regulus.evalyn.ai/document/49-cfr-180-203.json","markdown":"https://regulus.evalyn.ai/document/49-cfr-180-203.md"},"app_url":"https://regulus.evalyn.ai/document/49-cfr-180-203","source_url":"https://www.ecfr.gov/on/2026-08-18/title-49/section-180.203","body":"As used in this section, the word “cylinder” includes UN pressure receptacles. In addition to the definitions contained in § 171.8 of this subchapter, the following definitions apply to this subpart:\n\nCommercially free of corrosive components means a hazardous material having a moisture content less than 55 ppm and free of components that will adversely react with the cylinder (e.g., chemical stress corrosion).\n\nCondemn means a determination that a cylinder is unserviceable for the continued transportation of hazardous materials in commerce and that the cylinder may not be restored by repair, rebuilding, requalification, or any other procedure.\n\nFilled or charged means an introduction or presence of a hazardous material in a cylinder.\n\nMobile unit means a vehicle specifically authorized under a RIN to carry out requalification operations identified under the RIN within specified geographic areas away from the principle place of business. Mobile units must comply with the requirements outlined in the approval issuance letter from the Associate Administrator for Hazardous Materials Safety (see § 107.805 of subchapter A of this chapter).\n\nNon-corrosive service means a hazardous material that, in the presence of moisture, is not corrosive to the materials of construction of a cylinder (including valve, pressure relief device, etc.).\n\nOver-heated means a condition in which the temperature of any portion of an aluminum cylinder has reached 176 °C (350 °F) or higher, or in which the temperature of any portion of a steel or nickel cylinder has reached 343 °C (650 °F) or higher.\n\nOver-pressurized means a condition in which the internal pressure applied to a cylinder has reached or exceeded the yield point of the cylinder.\n\nPermanent expansion means a permanent increase in a cylinder's volume after the test pressure is released.\n\nProof pressure test means a liquid-based pressure test by interior pressurization without the determination of a cylinder's expansion.\n\nRebuild means the replacement of a pressure part (e.g. a wall, head, or pressure fitting) by welding.\n\nRepair means a procedure for correction of a rejected cylinder that may involve welding.\n\nRequalification means the completion of a visual inspection and/or the test(s) required to be performed on a cylinder to determine its suitability for continued service.\n\nRequalification identification number or RIN means a code assigned by DOT to uniquely identify a cylinder requalification, repair, or rebuilding facility.\n\n[67 FR 51660, Aug. 8, 2002, as amended at 71 FR 33894, June 12, 2006; 85 FR 85432, Dec. 28, 2020]","truncated":false,"body_characters":2605}