46 CFR 56.97-1 - General (replaces 137).

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§ 56.97-1 General (replaces 137).

(a)Scope. The requirements in this subpart apply to pressure tests of piping in lieu of 137 of ASME B31.1 (incorporated by reference; see 46 CFR 56.01-2). Those paragraphs reproduced are so noted.

(b)Leak tightness. It is mandatory that the design, fabrication and erection of piping constructed under the regulations in this subchapter demonstrate leak tightness. Except where otherwise permitted in this subpart, this requirement must be met by a hydrostatic leak test prior to initial operations. Where a hydrostatic test is not practicable, a pneumatic test ( § 56.97-35) or initial service leak test ( § 56.97-38) may be substituted if approved by the Commandant.

(1) At no time during the hydrostatic test may any part of the piping system be subjected to a stress greater than 90 percent of its yield strength (0.2 percent offset) at test temperature.

(2) Pneumatic tests may be used in lieu of the required hydrostatic test (except as permitted in paragraph (b)(3) of this section), only when -

(i) Piping subassemblies or systems are so designed or supported that they cannot be safely filled with water; 1 or

1 These tests may be made with the item being tested partially filled with water, if desired.

(ii) Piping subassemblies or systems are to be used in services where traces of the testing medium cannot be tolerated and, whenever possible, the piping subassemblies or system have been previously hydrostatically tested to the pressure required in § 56.97-30(e).

(3) A pneumatic test at a pressure not to exceed 25 psig may be applied before a hydrostatic or a pneumatic test as a means of locating major leaks. The preliminary pneumatic test must be carried out in accordance with the requirements of § 56.97-35.


Compressed gas is hazardous when used as a testing medium. It is, therefore, recommended that special precautions for protection of personnel be taken whenever gas under pressure is used as the test medium.

(4) The hydrostatic test of the piping system, when conducted in accordance with the requirements of this part, is acceptable as the test for piping subassemblies and may also be used in lieu of any such test required by the material specification for material used in the piping subassembly or system provided the minimum test pressure required for the piping system is met, except where the installation would prevent performing any nondestructive examination required by the material specification to be performed subsequent to the hydrostatic or pneumatic test.

[CGD 73-254, 40 FR 40167, Sept. 2, 1975, as amended by USCG-2003-16630, 73 FR 65185, Oct. 31, 2008]

This is a list of United States Code sections, Statutes at Large, Public Laws, and Presidential Documents, which provide rulemaking authority for this CFR Part.

This list is taken from the Parallel Table of Authorities and Rules provided by GPO [Government Printing Office].

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United States Code
Presidential Documents

Executive Order ... 12234

Executive Order ... 12777

Title 46 published on 16-Dec-2017 03:49

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 46 CFR Part 56 after this date.

  • 2016-07-22; vol. 81 # 141 - Friday, July 22, 2016
    1. 81 FR 48220 - Harmonization of Standards for Fire Protection, Detection, and Extinguishing Equipment
      GPO FDSys XML | Text
      Final rule.
      This final rule is effective August 22, 2016. The incorporation by reference of certain publications listed in the rule is approved by the Director of the Federal Register on August 22, 2016.
      33 CFR Parts 140, 145, 148, and 149
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