Certain material is incorporated by reference into this part with the approval of the Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other than that specified in this section, the Coast Guard must publish a document in the Federal Register and the material must be available to the public. All approved incorporation by reference (IBR) material is available for inspection at the U.S. Coast Guard and the National Archives and Records Administration (NARA). Contact U.S. Coast Guard Headquarters at: Commandant (CG-ENG), Attn: Office of Design and Engineering Standards, U.S. Coast Guard Stop 7509, 2703 Martin Luther King Jr. Avenue SE, Washington, DC 20593-7509; phone (202) 372-1375; email [email protected]. For information on the availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected]. The material may be obtained from the following sources:

(a) American Society of Mechanical Engineers (ASME), Two Park Avenue, New York, NY 10016-5990; 800-843-2763; [email protected]; www.asme.org.

(1) ASME BPVC.VIII.1-2019, 2019 ASME Boiler and Pressure Vessel Code, Section VIII, Division 1, Rules for Construction of Pressure Vessels, 2019 Edition, issued July 1, 2019 (“Section VIII of the ASME BPVC”); IBR approved for §§ 54.01-2; 54.01-5 (c), (e), and table 2; 54.01-18(b); 54.01-25(a); 54.01-30; 54.01-35(a), (b), and (e); 54.03-1; 54.05-1; 54.10-1; 54.10-3(b); 54.10-5(a), (b), and table 1; 54.10-10(b) and (e); 54.10-15(c); 54.15-1(a); 54.15-5(a); 54.15-10(e) and (h); 54.15-13(a); 54.20-1(a); 54.20-3(b), (c), and (d); 54.25-1; 54.25-3; 54.25-8(b); 54.25-10(b) and (c); 54.25-15; 54.25-20(b), (c), and (e); 54.30-3(c); 54.30-5(a); 54.30-10(a).

(2) [Reserved]

(b) ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959; 610-832-9500; [email protected]; www.astm.org.

(1) ASTM A20/A20M-19, Standard Specification for General Requirements for Steel Plates for Pressure Vessels, approved May 1, 2019 (“ASTM A20/A20M”); IBR approved for §§ 54.05-10(a); 54.25-10(b).

(2) ASTM A203/A203M-17, Standard Specification for Pressure Vessel Plates, Alloy Steel, Nickel, approved November 1, 2017 (“ASTM A203/A203M”); IBR approved for § 54.05-20(b).

(3) ASTM A370-19, Standard Test Methods and Definitions for Mechanical Testing of Steel Products, approved July 1, 2019 (“ASTM A370”); IBR approved for § 54.25-20(b).

(4) ASTM E23-18, Standard Test Methods for Notched Bar Impact Testing of Metallic Materials, approved June 1, 2018 (“ASTM E23”); IBR approved for § 54.05-5(a).

(5) ASTM E208-19, Standard Test Method for Conducting Drop-Weight Test to Determine Nil-Ductility Transition Temperature of Ferritic Steels, approved October 1, 2019 (“ASTM E208”); IBR approved for § 54.05-5(b) and (c).

(c) Compressed Gas Association (CGA), 8484 Westpark Drive, Suite 220, McLean, VA 22012; 703-788-2700; www.cganet.com.

(1) CGA S-1.2-2009, Pressure Relief Device Standards—Part 2—Portable Containers for Compressed Gases, Ninth Edition, 2009 (“CGA S-1.2”); IBR approved for § 54.15-10(h).

(2) [Reserved]

(d) Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. (MSS), 127 Park Street NE, Vienna, VA 22180-4602; 703-281-6613; www.msshq.org.

(1) ANSI/MSS SP-25-2018, Standard Marking System for Valves, Fittings, Flanges and Unions, published September 2018 (“MSS SP-25”); IBR approved for § 54.01-25(b).

(2) [Reserved]

(a) Pressure vessels must be designed, constructed, and inspected in accordance with Section VIII of the ASME BPVC (incorporated by reference, see § 54.01-1), as limited, modified, or replaced by specific requirements in this part. The provisions in the appendices to Section VIII of the ASME BPVC are adopted and must be followed when the requirements in Section VIII make them mandatory. For general information, table 1 to § 54.01-2(a) lists the various paragraphs in Section VIII of the ASME BPVC that are limited, modified, or replaced by regulations in this part.

(b) References to the ASME BPVC, such as paragraph UG-125, indicate:

(1) U = Division 1 of Section VIII of the ASME BPVC.

(2) G = Part containing general requirements.

(3) 125 = Paragraph within part.

(c) When a paragraph or a section of the regulations in this part relates to material in Section VIII of the ASME BPVC, the relationship with the code will be shown immediately following the heading of the section or at the beginning of the paragraph, as follows:

(1) (Modifies U__.) This indicates that the material in U__ is generally applicable but is being altered, amplified or augmented.

(2) (Replaces U__.) This indicates that U__ does not apply.

(3) (Reproduces U__.) This indicates that U__ is being identically reproduced for convenience, not for emphasis.

(a) This part contains requirements for pressure vessels. Table 1 to § 54.01-5 gives a breakdown by parts in this subchapter of the regulations governing various types of pressure vessels, boilers, and thermal units.

(b) Pressure vessels are divided into Classes I, I-L (low temperature), II, II-L (low temperature), and III. Table 2 to § 54.01-5 describes these classes and sets out additional requirements for welded pressure vessels.

(c) The requirements for pressure vessels by class are as follows:

(1) Class I-L and II-L pressure vessels must meet the applicable requirements in this part.

(2) Pressure vessels containing hazardous materials as defined in § 150.115 of this chapter must meet the requirements of this part or, as applicable, the requirements in 49 CFR parts 171-177, or part 64 of this subchapter.

(3) Except as provided in paragraph (c)(4) of this section, Classes I, II, and III pressure vessels not containing hazardous materials must be designed and constructed in accordance with the requirements in Section VIII of the ASME BPVC (incorporated by reference; see § 54.01-1) and must be stamped with the ASME “U” symbol. These pressure vessels must also comply with the requirements that are listed or prescribed in paragraphs (d) through (g) of this section. Compliance with other provisions in this part is not required.

(4) Classes II and III pressure vessels that have a net internal volume of less than 0.14 cubic meters (5 cubic feet) and do not contain hazardous materials must be stamped with either the ASME “U” or “UM” symbol. Compliance with other provisions in this part is not required.

(d) Pressure vessels described in paragraph (c)(3) of this section must—

(1) Have detailed plans that include the information required by § 54.01-18;

(2) Meet §§ 54.01-35, 54.20-3(c), and 54.25-3;

(3) Have pressure relief devices required by subpart 54.15;

(4) Meet the applicable requirements in §§ 54.10-3, 54.10-20, and 54.10-25 for inspection, reports, and stamping;

(5) If welded, meet the post weld heat treatment and minimum joint and radiography requirement in table 2 to § 54.01-5; and

(6) If a steam generating pressure vessel, meet § 54.01-10.

(e) The plans required by paragraph (d)(1) of this section must be certified by a registered professional engineer to meet the design requirements in paragraph (d) of this section and in Section VIII of the ASME BPVC. The certification must appear on all drawings and analyses. The plans must be made available to the Coast Guard prior to the inspection required by § 54.10-3(c).

(f) If a pressure vessel has more than one independent chamber and the chambers have different classifications, each chamber must, as a minimum, meet the requirements for its classification. If a single classification for the entire pressure vessel is preferred, the classification selected must be one that is required to meet all of the regulations applicable to the classification that is not selected. For example, if one chamber is Class I and one chamber is Class II-L, the only single classification that can be selected is Class I-L.

(g) The design pressure for each interface between two chambers in a multichambered pressure vessel must be—

(1) The maximum allowable working pressure (gauge) in the chamber with the higher pressure; or

(2) If one chamber is a vacuum chamber, the maximum allowable working pressure (absolute) in the other chamber minus the least operating pressure (absolute) in the vacuum chamber.

(a) Pressure vessels in which steam is generated are classed as “Unfired Steam Boilers” except as required otherwise by paragraph (b) of this section. Unfired steam boilers must be fitted with an efficient water level indicator, a pressure gage, a blowdown valve, and an approved safety valve as required by § 54.15-15. Unfired steam boilers must be constructed in accordance with this part other than when the pressures are more than 206 kPa (30 psig) or the temperatures of the working fluid are more than 454 °C (850 °F) when such boilers must be constructed in accordance with part 52 of this subchapter.

(b) Vessels known as “Evaporators” or “Heat Exchangers” are not classified as unfired steam boilers. They must be fitted with an approved safety device as required under § 54.15-15 and constructed in accordance with this part.

(c) An evaporator in which steam is generated must be fitted with an efficient water level indicator, a pressure gage, and a blowdown valve.

(a) The following classifications are exempt from shop inspection and plan approval requirements of this part:

(1) Vessels containing water at a pressure not greater than 689 kPa (100 psig), and at a temperature not above 93 °C (200 °F) including those containing air, the compression of which serves only as a cushion. Air-charging lines may be permanently attached if the air pressure does not exceed 103 kPa (15 psig).

(2)(i) Hot water supply storage tanks heated by steam or any other indirect means when none of the following limitations is exceeded:

(A) A heat input of 58 kW (200,000 Btu per hour);

(B) A water temperature of 93 °C (200 °F);

(C) A nominal water-containing capacity of 454 liters (120 gallons); or

(D) A pressure of 689 kPa (100 psig).

(ii) The exemption of any tank under this paragraph (a)(2) requires that it must be fitted with a safety relief valve of at least 1-inch diameter, set to relieve below the maximum allowable working pressure of the tank.

(3)(i) Vessels having an internal operating pressure not exceeding 103 kPa (15 psig) with no limitation on size.

(ii) Cargo tanks of pressure vessel configuration are not included in the exemption in paragraph (a)(3)(i) of this section.

(4) Class I, II, and III pressure vessels that meet the requirements of § 54.01-5(c)(3) and (4).

(5) Condensers and heat exchangers, regardless of size, when the design is such that the liquid phase is not greater than 689 kPa (100 psig) and 200 °F (93 °C) and the vapor phase is not greater than 103 kPa (15 psig) provided that the Officer in Charge, Marine Inspection is satisfied that system overpressure conditions are addressed by the owner or operator.

(b) For fluid conditioner fittings see § 56.15-1 of this subchapter.

Pressure vessels for human occupancy (PVHOs) must meet the requirements of subpart B (Commercial Diving Operations) of part 197 of this chapter.

(a) Manufacturers intending to fabricate pressure vessels, heat exchangers, evaporators, and similar appurtenances, covered by the regulations in this part must submit detailed plans in accordance with subpart 50.20 of this subchapter except as provided in paragraph (c) of this section.

(b) The following information must be submitted:

(1) Calculations for all pressure containment components including the maximum allowable working pressure, the hydrostatic or pneumatic test pressure, and the intended safety device setting.

(2) Joint design and methods of attachment of all pressure containment components.

(3) Foundations and supports (design and attachment).

(4) Pertinent calculations for pressure vessel foundations and/or supports.

(5) A bill of material meeting the requirements of Section VIII of the ASME BPVC (incorporated by reference; see § 54.01-1), as modified by this part.

(6) A diagrammatic arrangement drawing of the assembled unit indicating location of internal and external components.

(c) Plans for Class I, II, and III pressure vessels with the ASME “U” stamp that do not contain hazardous materials are not required to be submitted for approval (see § 54.01-5(e)).

(a) Pressure components for pressure vessels must be as required by UG-11 of Section VIII of the ASME BPVC (incorporated by reference; see § 54.01-1) except as noted otherwise in this section.

(b) All pressure components conforming to an accepted ANSI (American National Standards Institute) Standard referred to in an adopted code, specification or standard or in this subchapter must also be marked in accordance with MSS SP-25 (incorporated by reference; see § 54.01-1).

(a) The loadings for pressure vessels must be as required by UG-22 of Section VIII of the ASME BPVC (incorporated by reference; see § 54.01-1) except as noted otherwise in this section.

(b) In evaluating loadings for certain pressure vessel applications, the Commandant may require consideration of the following loads in addition to those listed in UG-22 of Section VIII of the ASME BPVC:

(1) Loading imposed by vessel's attitude in roll, list, pitch and trim.

(2) Dynamic forces due to ship motions.

(a) Vessels or portions of vessels subject to corrosion must be as required by UG-25 of Section VIII of the ASME BPVC (incorporated by reference; see § 54.01-1) except as noted otherwise in this section.

(b) The pressure portions of pressure vessels must:

(1) Normally have a corrosion allowance of one-sixth of the calculated thickness, or one-sixteenth inch, whichever is smaller, added to the calculated thickness as determined by the applicable design formula.

(2) Be specifically evaluated in cases where unusually corrosive cargoes will be involved, for the possible increase of this corrosion allowance.

(3) Have no additional thickness required when acceptable corrosion resistant materials are used.

(4) Not normally need additional thickness allowance when the effective stress (either S or SE depending on the design formula used) is 80 percent or less of the allowable stress listed in Section VIII of the ASME BPVC for calculating thickness.

(c) Telltale holes must not be permitted in pressure vessels containing dangerous fluids, such as acid, poison, corrosives, etc.

(d) Exemption from these corrosion allowance requirements will be granted by the Commandant in those cases where:

(1) The contents of the pressure vessel are judged to be sufficiently noncorrosive; and,

(2) Where the external surface is also protected from corrosion. A suitable vapor barrier is adequate protection, while paint or other thin coatings exposed to weather or mechanical damage are not acceptable.

(e) No applied linings except as provided in part UCL of Section VIII of the ASME BPVC are acceptable.

(a) The exemption from external pressure consideration provided by the note under UG-28(f) does not apply.

(b) Vessels which may at times be subjected to partial vacuum due to nature of the contents, temperature, unloading operations, or other facet of employment must either have vacuum breaker protection or be designed for not less than one-half atmosphere of external pressure.