{"operation":"document","citation":"49 CFR 179.200-4","title":"-4 Insulation.","source_type":"regulation","agency":"Pipeline and Hazardous Materials Safety Administration","status":"current","official":true,"published_on":null,"effective_on":"2026-08-18","summary":"(a) If insulation is applied, the tank shell and expansion dome when used must be insulated with an approved material. The entire insulation must be covered with a metal jacket of a thickness not less than 11 gauge (0.1196 inch) nominal (Manufacturer's Standard Gauge) and flashed around all openings","machine_formats":{"json":"https://regulus.evalyn.ai/document/49-cfr-179-200-4.json","markdown":"https://regulus.evalyn.ai/document/49-cfr-179-200-4.md"},"app_url":"https://regulus.evalyn.ai/document/49-cfr-179-200-4","source_url":"https://www.ecfr.gov/on/2026-08-18/title-49/section-179.200-4","body":"(a) If insulation is applied, the tank shell and expansion dome when used must be insulated with an approved material. The entire insulation must be covered with a metal jacket of a thickness not less than 11 gauge (0.1196 inch) nominal (Manufacturer's Standard Gauge) and flashed around all openings so as to be weather tight. The exterior surface of a carbon steel tank and the inside surface of a carbon steel jacket must be given a protection coating.\n\n(b) If insulation is a specification requirement, it shall be of sufficient thickness so that the thermal conductance at 60 °F is not more than 0.225 Btu per hour, per square foot, per degree F temperature differential, unless otherwise provided in § 179.201-1. If exterior heaters are attached to tank, the thickness of the insulation over each heater element may be reduced to one-half that required for the shell.\n\n[29 FR 18995, Dec. 29, 1964. Redesignated at 32 FR 5606, Apr. 5, 1967, and amended by Amdt. 179-10, 36 FR 21349, Nov. 6, 1971; Amdt. 179-50, 60 FR 49078, Sept. 21, 1995]","truncated":false,"body_characters":1044}