{"operation":"document","citation":"49 CFR 178.272-2","title":"Minimum thickness of shells and heads.","source_type":"regulation","agency":"Pipeline and Hazardous Materials Safety Administration","status":"historical","official":true,"published_on":null,"effective_on":"2005-10-01","summary":"(a) The approval agency may authorize a minimum thickness less than that required by § 178.270-5 of this subpart where additional protection against tank puncture provides equal integrity.\n\n(b) The shell and head thickness of a tank must be at least:\n\n(1) 3.18 mm (0.125 inches) for a tank with a max","machine_formats":{"json":"https://regulus.evalyn.ai/document/49-cfr-178-272-2.json","markdown":"https://regulus.evalyn.ai/document/49-cfr-178-272-2.md"},"app_url":"https://regulus.evalyn.ai/document/49-cfr-178-272-2","source_url":"https://www.govinfo.gov/app/details/CFR-2005-title49-vol2/CFR-2005-title49-vol2-sec178-272-2","body":"(a) The approval agency may authorize a minimum thickness less than that required by § 178.270-5 of this subpart where additional protection against tank puncture provides equal integrity.\n\n(b) The shell and head thickness of a tank must be at least:\n\n(1) 3.18 mm (0.125 inches) for a tank with a maximum cross-sectional dimension of 1.8 m (5.9 feet) or less; or\n\n(2) 4 mm (0.157 inches) for a tank constructed of the reference mild steel having a maximum cross-sectional dimension exceeding 1.8 m (5.9 feet). For tanks having a maximum cross-sectional dimension exceeding 1.8 m (5.9 feet) constructed of other steels, an equivalent head and shell thickness calculated in accordance with § 178.270-5(c) of this subpart may be used, subject to an absolute minimum of 3.18 mm (0.125 inches).\n\n(c) The following additional puncture protection systems are authorized:\n\n(1) An overall external structural protection, such as a jacket, which is rigidly secured to the tank with a layer of cushioning material installed between the external structural protection and the tank; or\n\n(2) A complete framework surrounding the tank including both longitudinal and transverse structural members.\n\n[Amdt. 178-65, 46 FR 9899, Jan. 29, 1981, as amended at 66 FR 45387, Aug. 28, 2001]","truncated":false,"body_characters":1267}