1625-0097 Stat/Authority

46 CFR Part 50 (up to date as of 8/05/2024)
General Provisions

46 CFR Part 50 (Aug. 5, 2024)

This content is from the eCFR and is authoritative but unofficial.

Title 46 —Shipping
Chapter I —Coast Guard, Department of Homeland Security
Subchapter F —Marine Engineering
Part 50 General Provisions
Subpart 50.01 Basis and Purpose of Regulations
§ 50.01-10 Purpose of regulations.
§ 50.01-15 Scope of regulations.
§ 50.01-20 OMB control numbers assigned pursuant to the Paperwork Reduction Act.
Subpart 50.05 Application
§ 50.05-1 General.
§ 50.05-5 Existing boilers, pressure vessels or piping systems.
§ 50.05-10 Alterations or repairs.
§ 50.05-15 Vessels subject to regulations in this subchapter.
§ 50.05-20 Steam-propelled motorboats.
Subpart 50.10 Definition of Terms Used in This Subchapter
§ 50.10-1 Commandant.
§ 50.10-5 Coast Guard District Commander or District Commander.
§ 50.10-10 Officer in Charge, Marine Inspection, (OCMI).
§ 50.10-15 Marine inspector or inspector.
§ 50.10-20 Headquarters.
§ 50.10-23 Marine Safety Center.
§ 50.10-25 Coast Guard Symbol.
§ 50.10-30 Coast Guard number.
§ 50.10-35 Constructed.
Subpart 50.20 Plan Submittal and Approval
§ 50.20-1 General.
§ 50.20-5 Procedures for submittal of plans.
§ 50.20-10 Number of copies of plans required.
§ 50.20-15 Previously approved plans.
§ 50.20-25 Calculations.
§ 50.20-30 Alternative materials or methods of construction.
§ 50.20-33 [Reserved]
§ 50.20-35 Marine inspector's decisions.
§ 50.20-40 Right of appeal.
Subpart 50.25 Acceptance of Material and Piping Components
§ 50.25-1 General.
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46 CFR Part 50 (up to date as of 8/05/2024)
General Provisions

46 CFR Part 50 (Aug. 5, 2024)

§ 50.25-3 Manufacturer or mill certification.
§ 50.25-5 Products requiring manufacturer or mill certification.
§ 50.25-7 Testing of products required to be certified in presence of marine inspector.
§ 50.25-10 Acceptance of piping components by specific letter or approved plan.
Subpart 50.30 Fabrication Inspection
§ 50.30-1 Scope.
§ 50.30-10 Class I, I-L and II-L pressure vessels.
§ 50.30-15 Class II pressure vessels.
§ 50.30-20 Class III pressure vessels.

PART 50—GENERAL PROVISIONS
Authority: 43 U.S.C. 1333; 46 U.S.C. 3306, 3703; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; Department
of Homeland Security Delegation No. 0170.1; Section 50.01-20 also issued under the authority of 44 U.S.C. 3507.

Link to an amendment published at 89 FR 50092, June 12, 2024.
Source: CGFR 68-82, 33 FR 18808, Dec. 18, 1968, unless otherwise noted.

Subpart 50.01—Basis and Purpose of Regulations
§ 50.01-10 Purpose of regulations.
Link to an amendment published at 89 FR 50092, June 12, 2024.
(a) The purpose of the regulations in this subchapter is to set forth minimum requirements for marine
engineering details for various types of vessels in accordance with the intent of title 52 of the Revised
Statutes and acts amendatory thereof or supplemental thereto as well as to implement various
international conventions for safety of life at sea and other treaties, which contain requirements affecting
marine engineering. The regulations in this subchapter have the force of law.
(b) All marine engineering details, such as boilers, pressure vessels, main and auxiliary machinery, piping,
valves, and fittings, shall be designed, constructed, and installed in accordance with the provisions of this
subchapter, except when specifically modified by the regulations in another subchapter in this chapter for
a particular type of vessel or where a specific installation may be required or permitted.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, CGD 95-012, 60 FR 48049, Sept. 18, 1995]

§ 50.01-15 Scope of regulations.
(a) This subchapter provides the specifications, standards and requirements for strength and adequacy of
design, construction, installation, inspection, and choice of materials for machinery, boilers, pressure
vessels, safety valves, and piping systems upon which safety of life is dependent.

46 CFR 50.01-15(a) (enhanced display)

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46 CFR Part 50 (up to date as of 8/05/2024)
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46 CFR 50.01-15(b)

(b) Since this subchapter contains the marine engineering details, it implements the requirements for
inspection and certification of vessels as set forth in other subchapters for specific types of vessels.
(c) The regulations in this subchapter (parts 50, 52, 53, 54, 56, 57, 58, 59, and 61 through 64) have preemptive
effect over state or local regulations in the same field.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by USCG-2012-0196, 81 FR 48250, July 22, 2016]

§ 50.01-20 OMB control numbers assigned pursuant to the Paperwork Reduction Act.
(a) Purpose. This section collects and displays the control numbers assigned to information collection and
recordkeeping requirements in this subchapter by the Office of Management and Budget (OMB) pursuant
to the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.). The Coast Guard intends that this
section comply with the requirements of 44 U.S.C. 3507(f) which requires that agencies display a current
control number assigned by the Director of the OMB for each approved agency information collection
requirement.
(b) Display.
46 CFR Part or Section where Identified or Described

Current OMB Control No.

Parts 50 through 64

1625-0097

[49 FR 38120, Sept. 27, 1984, as amended by CGD 88-072, 53 FR 34297, Sept. 6, 1988; USCG-2004-18884, 69 FR 58345, Sept. 30,
2004]

Subpart 50.05—Application
Link to an amendment published at 89 FR 50092, June 12, 2024.
§ 50.05-1 General.
(a) The regulations in this subchapter shall apply to the marine engineering details of installations on vessels
required to be inspected and certificated under other subchapters in this chapter as described in §
50.01-10.
(b) The regulations in this subchapter are not retroactive in effect, except as provided in § 50.05-5 or §
50.05-10, or if specifically so provided for at the time specific regulations are amended or added.
(c) The requirements in this subchapter revised or added subsequent to July 1, 1969, shall be applicable to
the installations contracted for after the effective dates of such requirements. Normally, materials, items
of equipment, or installations in vessels which have been accepted and passed as satisfactory and
meeting the applicable requirements in this subchapter then in effect and which are maintained in good
and serviceable condition to the satisfaction of the Officer in Charge, Marine Inspection, may be continued
in use until replacement is deemed necessary by such officer or as specified in the regulations.
(d) Items of equipment, which are in use on vessels, previously approved by the Commandant but not
complying with the latest specification requirements may be continued in use so long as they are
maintained in good and serviceable condition to the satisfaction of the Officer in Charge, Marine
Inspection, until replacement is deemed necessary by such officer or as specified in the regulations.

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46 CFR Part 50 (up to date as of 8/05/2024)
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46 CFR 50.05-1(e)

(e) Industrial systems and components on mobile offshore drilling units must meet subpart 58.60 of this
chapter.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 73-251, 43 FR 56799, Dec. 4, 1978; CGD 77-147, 47 FR 21809, May
20, 1982; USCG-2000-7790, 65 FR 58459, Sept. 29, 2000]

§ 50.05-5 Existing boilers, pressure vessels or piping systems.
(a) Whenever doubt exists as to the safety of an existing boiler, pressure vessel, or piping system, the marine
inspector may require that it be gaged or checked to determine the extent of deterioration, and if
necessary for safety may require the recalculation and reduction of the maximum allowable working
pressure.
(b) For the purpose of recalculating the maximum allowable working pressure of boilers, pressure vessels, or
piping which have deteriorated in service, the applicable design formulas in effect at the time it was
contracted for or built or the currently effective design formulas in this subchapter shall be used: Provided,
That such recalculation based on currently effective design formulas in this subchapter does not permit a
higher pressure than that originally allowed by the regulations in effect at the time such work was
contracted for or built.
(c) When existing vessels are reboilered, the mountings and attachments shall be renewed in accordance
with the regulations in this subchapter in effect at the time such reboilering work is contracted for. The
existing steam piping shall be examined. Those portions which are in good condition and comply with
minimum thickness requirements in effect at the time such reboilering work is contracted for may be
continued in service. The steam piping replaced shall be in accordance with the regulations in this
subchapter in effect for new construction.
(d) For the purpose of this section, existing equipment includes only items which have previously met all
Coast Guard requirements for installation aboard a vessel certificated by the Coast Guard, including
requirements for design, fabrication, testing, and inspection at the time the equipment was new.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 81-79, 50 FR 9430, Mar. 8, 1985]

§ 50.05-10 Alterations or repairs.
(a) When alteration or repair of boilers, pressure vessels, machinery, safety valves or piping systems becomes
necessary, the work shall be done under the cognizance of the Officer in Charge Marine Inspection. It shall
be done in accordance with the regulations in effect at the time such vessel or installation was contracted
for or built (whichever is latest), or in accordance with the regulations in effect for new construction.
(b) When alterations or repairs are made to a U.S. flag vessel in a port or place not in the United States, a
notice containing details of the proposed alterations or repairs must be submitted to the appropriate
Officer in Charge, Marine Inspection.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 73-251, 43 FR 56799, Dec. 4, 1978]

46 CFR 50.05-10(b) (enhanced display)

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46 CFR Part 50 (up to date as of 8/05/2024)
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46 CFR 50.05-15

§ 50.05-15 Vessels subject to regulations in this subchapter.
(a) Passenger vessels, tank vessels, cargo and miscellaneous vessels, nautical schoolships, mobile offshore
drilling units, and oceanographic vessels are subject to the regulations in this subchapter to the extent
prescribed by various laws and regulations as described in § 50.01-1. The applicable provisions in this
subchapter shall apply to all such U.S. flag vessels, and to all such foreign vessels which carry
passengers from any port in the United States except as follows:
(1) Any vessel of a foreign nation signatory to the International Convention for Safety of Life at Sea,
1974, and which has on board a current, valid Convention certificate attesting to the sufficiency of
the marine engineering details as prescribed by applicable regulations in this chapter.
(2) Any vessel of a foreign nation having inspection laws approximating those of the United States
together with reciprocal inspection arrangements with the United States, and which has on board a
current, valid certificate of inspection issued by its government under such arrangements.
(3) Any vessel operating exclusively on inland waters which are not navigable waters of the United
States.
(4) Any vessel laid up and dismantled and out of commission.
(5) With the exception of vessels of the U.S. Maritime Administration, any vessel with the title vested in
the United States and which is used for public purposes.
(b) Notwithstanding the exceptions previously noted in paragraphs (a) (1) and (2) of this section, foreign
vessels of novel design or construction or whose operation involves potential unusual risks shall be
subject to inspection to the extent necessary to safeguard life and property in U.S. ports, as further
provided by § 2.01-13 in subchapter A (Procedures Applicable to the Public) of this chapter.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 73-251, 43 FR 56799, Dec. 4, 1978; CGD 80-161, 48 FR 15472, Apr.
11, 1983; CGD 90-008, 55 FR 30660, July 26, 1990; CGD 95-012, 60 FR 48049, Sept. 18, 1995]

§ 50.05-20 Steam-propelled motorboats.
(a) The requirements covering design of the propelling engine, boiler, and the auxiliary machinery, and the
inspection thereof on all motor boats which are more than 40 feet in length and which are propelled by
machinery driven by steam shall be in accordance with the applicable provisions of this subchapter.
(b) If the engines, boilers, and auxiliary machinery are found to be in safe operating condition at the initial or
subsequent periodical inspection, the Officer in Charge, Marine Inspection, shall issue a letter to that
effect. Such letter shall be posted on the vessel under glass. The letter will be valid for a specified period
of time, as determined by the Officer in Charge, Marine Inspection. The owner, within 30 days prior to its
expiration, shall make application to the nearest Officer in Charge, Marine Inspection for a renewal
thereof.

Subpart 50.10—Definition of Terms Used in This Subchapter
§ 50.10-1 Commandant.
The term Commandant means the Commandant U.S. Coast Guard.

46 CFR 50.10-1 (enhanced display)

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46 CFR Part 50 (up to date as of 8/05/2024)
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46 CFR 50.10-5

§ 50.10-5 Coast Guard District Commander or District Commander.
The term Coast Guard District Commander or District Commander means an officer of the Coast Guard designated
as such by the Commandant to command all Coast Guard activities within his district, which include the
inspections, enforcement, and administration of Subtitle II, Title 46, U.S. Code, Title 46 and Title 33 U.S. Code, and
regulations under these statutes.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 95-028, 62 FR 51200, Sept. 30, 1997]

§ 50.10-10 Officer in Charge, Marine Inspection, (OCMI).
The term Officer in Charge, Marine Inspection, (OCMI) means any person from the civilian or military branch of the
Coast Guard designated as such by the Commandant and who, under the superintendence and direction of the
Coast Guard District Commander, is in charge of an inspection zone for the performance of duties with respect to
the inspections, enforcement, and administration of Subtitle II, Title 46, U.S. Code, Title 46 and Title 33 U.S. Code,
and regulations under these statutes.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 95-028, 62 FR 51200, Sept. 30, 1997]

§ 50.10-15 Marine inspector or inspector.
The term marine inspector or inspector means any person from the civilian or military branch of the Coast Guard
assigned under the superintendence and direction of an Officer in Charge, Marine Inspection, or any other person as
may be designated for the performance of duties with respect to the inspections, enforcement and the
administration of Subtitle II, Title, 46, U.S. Code, Title 46 and Title 33, U.S. Code, and regulations under these
statutes.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 95-028, 62 FR 51200, Sept. 30, 1997]

§ 50.10-20 Headquarters.
Link to an amendment published at 89 FR 50093, June 12, 2024.
The term Headquarters means the Commandant (CG-00), Attn: Commandant, U.S. Coast Guard Stop 7000, 2703
Martin Luther King Jr. Avenue SE., Washington, DC 20593-7000.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 88-070, 53 FR 34534, Sept. 7, 1988; USCG-2013-0671, 78 FR
60147, Sept. 30, 2013]

§ 50.10-23 Marine Safety Center.
Link to an amendment published at 89 FR 50093, June 12, 2024.
The term Marine Safety Center refers to the Commanding Officer, Marine Safety Center, U.S. Coast Guard, 2703
Martin Luther King Jr. Avenue SE., Washington, DC 20593 for visitors. Send all mail to Commanding Officer (MSC),
Attn: Marine Safety Center, U.S. Coast Guard Stop 7430, 2703 Martin Luther King Jr. Avenue SE., Washington, DC
20593-7430, in a written or electronic format. Information for submitting the VSP electronically can be found at
http://www.uscg.mil/HQ/MSC.
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46 CFR 50.10-25

[USCG-2016-0498, 82 FR 35089, July 28, 2017]

§ 50.10-25 Coast Guard Symbol.
Link to an amendment published at 89 FR 50094, June 12, 2024.
(a) The term Coast Guard Symbol means that impression stamped on the nameplates of boilers, pressure
vessels, and safety valves by a marine inspector upon the satisfactory completion of the tests and
inspection of the product. It may also be used by a marine inspector to identify workmanship test plates
and welding samples.
(b) The impression of the Coast Guard Symbol for stamping nameplates and specimens is shown in Figure
50.10-25(b).

FIGURE 50.10-25(B)—COAST GUARD SYMBOL
§ 50.10-30 Coast Guard number.
Link to an amendment published at 89 FR 50094, June 12, 2024.
(a) The Coast Guard number means that number assigned to boilers and pressure vessels by the Officer in
Charge, Marine Inspection, who makes the final tests and inspections.
(b) The Coast Guard number shall be stamped on the nameplates of boilers and pressure vessels.
(c) The Coast Guard number is comprised of the following:
(1) Three capital letters which identify the office of the issuing Officer in Charge, Marine Inspection (see
table 50.10-30); followed by,
(2) An OCMI serial number, by which the particular boiler or pressure vessel can be identified; the first
two digits of which will identify the calendar year the number was assigned.

46 CFR 50.10-30(c)(2) (enhanced display)

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46 CFR 50.10-30(c)(2)

Table 50.10-30—Previous Sector Office Identification Letters in Coast Guard
Numbers for Boilers and Pressure Vessels
Sector
Office

Identification
ALB

Albany.

ANC

Anchorage.

BAL

Baltimore.

BOS

Boston.

BUF

Buffalo.

CHA

Charleston.

CHI

Chicago.

CIN

Cincinnati.

CLE

Cleveland.

COR

Corpus Christi.

DET

Detroit.

DUL

Duluth.

GAL

Galveston.

GUA

Guam.

HON

Honolulu.

HOU

Houston.

HRV

Hampton Roads, VA.

HUN

Huntington.

JAC

Jacksonville.

JUN

Juneau.

LIS

Long Island.

LOS

Los Angeles.

LOU

Louisville.

MEM

Memphis.

MIA

Miami.

MIL

Milwaukee.

MIN

Minneapolis.

MOB

Mobile.

MOR

Morgan City.

NAS

Nashville.

NEW

New Orleans.

NYC

New York.

PAD

Paducah.

PAT

Port Arthur.

PHI

Philadelphia.

PIT

Pittsburgh.

46 CFR 50.10-30(c)(2) (enhanced display)

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46 CFR 50.10-35

Sector
Office

Identification
POM

Portland, ME.

POR

Portland, OR.

PRO

Providence.

ROT

Rotterdam.

SAV

Savannah.

SDC

San Diego.

SEA

Seattle.

SFC

San Francisco.

SIM

Saint Ignace.

SJP

San Juan.

SLM

St. Louis.

STB

Sturgeon Bay.

TAM

Tampa.

TOL

Toledo.

VAL

Valdez.

WNC

Wilmington, NC.

[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGFR 69-127, 35 FR 9975, June 17, 1970; CGD 74-219, 39 FR 40158,
Nov. 14, 1974; CGD 78-161, 44 FR 13492, Mar. 12, 1979; USCG-2000-7790, 65 FR 58459, Sept. 29, 2000; USCG-2006-25556, 72 FR
36330, July 2, 2007]

§ 50.10-35 Constructed.
The term constructed means the keel has been laid or, for vessels with no keel, assembly of at least 50 tons or 1% of
the estimated mass of all structural material, whichever is less, has been completed.
[CGD 83-043, 60 FR 24772, May 10, 1995]

Subpart 50.20—Plan Submittal and Approval
Link to an amendment published at 89 FR 50094, June 12, 2024.
§ 50.20-1 General.
(a) The required vessel, equipment, or installation plans, as listed in this subchapter, are general in character,
but include all plans which normally show the intended construction and safety features coming under the
cognizance of the Coast Guard. In a particular case, however, not all of the plans enumerated may be
applicable, and in such cases the Coast Guard will so notify the submitter.
(b) Manufacturers of pressure vessels and other components, which require specific fabrication inspection in
accordance with the requirements of this subchapter, shall submit and obtain approval of the applicable
construction plans prior to the commencement of such fabrication. Manufacturers of automatically

46 CFR 50.20-1(b) (enhanced display)

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46 CFR Part 50 (up to date as of 8/05/2024)
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46 CFR 50.20-5

controlled boilers shall submit and obtain approval of the applicable control system plans prior to
installation of the boiler. Manufacturers of boilers which must meet the requirements of part 52 of this
subchapter shall submit the applicable construction plans for review prior to installation.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 81-79, 50 FR 9431, Mar. 8, 1985]

§ 50.20-5 Procedures for submittal of plans.
(a) As the relative locations of shipyards, design offices, and Coast Guard offices vary throughout the country,
no specific routing will be required in the submittal of plans. In general, one of the procedures outlined in
this section apply, but if a more expeditious procedure can be used, there will normally be no objection to
it.
(b) The plans may be submitted in duplicate to the Officer in Charge, Marine Inspection, at or nearest the
place where the vessel is to be built. Alternatively, the plans may be submitted in triplicate to the Marine
Safety Center.
(c) In the case of classed vessels, upon specific request by the submitter, the American Bureau of Shipping
will arrange to forward the necessary plans to the Coast Guard indicating its action thereon. In this case,
the plans will be returned directly to the submitter as noted in paragraph (c) of this section.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 88-070, 53 FR 34534, Sept. 7, 1988; CGD 77-140, 54 FR 40598, Oct.
2, 1989; CGD 95-012, 60 FR 48049, Sept. 18, 1995; CGD 95-072, 60 FR 50462, Sept. 29, 1995]

§ 50.20-10 Number of copies of plans required.
(a) Three copies of each plan are normally required so that one copy can be returned to the submitter. If the
submitter desires additional copies of approved plans, a suitable number should be submitted to permit
the required distribution.

§ 50.20-15 Previously approved plans.
(a) A manufacturer wishing to fabricate equipment in accordance with a plan previously approved (including
work accomplished under a different contract) shall not be required to resubmit such plans provided:
(1) Certification is submitted that the proposed equipment conforms in every respect to the plan
previously approved, and such certification contains the drawing number, title, date, and last revision
or change date, and date of previous approval;
(2) The current regulations, including adopted specifications, standards or codes, pertaining to the
proposed equipment are the same as those current when the original plan was approved; and
(3) A copy of the approved plan is available for review by the approving office.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 77-140, 54 FR 40598, Oct. 2, 1989]

§ 50.20-25 Calculations.
(a) Calculations shall be forwarded with plans submitted for approval and shall clearly substantiate
compliance with the regulations in this subchapter. Care shall be taken to identify sources of equations,
factors and other information upon which the calculations are based.
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46 CFR 50.20-25(b)

(b) The results of the calculations, such as the maximum allowable working pressure (MAWP), test pressure,
and safety device settings, shall be clearly identified.

§ 50.20-30 Alternative materials or methods of construction.
(a) When new or alternative procedures, designs, or methods of construction are submitted for approval and
for which no regulations have been provided, the Commandant will act regarding the approval or
disapproval thereof.
(b) If, in the development of industrial arts, improved materials or methods of construction are developed,
their use in lieu of those specified will be given consideration upon formal application to the
Commandant, with full information as to their characteristics, together with such scientific data and
evidence as may be necessary to establish the suitability of such materials or methods of construction
for the purpose intended.

§ 50.20-33 [Reserved]
§ 50.20-35 Marine inspector's decisions.
(a) When it becomes necessary for a marine inspector to make decisions on matters covered by the
regulations in this subchapter or by requirements in referenced specifications, standards or codes, the
inspector shall inform the owner or his representative of the requirement, which will be identified by
source, section and paragraph number, on which the decisions are based. Whenever it is necessary to
make decisions in matters not specifically covered by the regulations in this subchapter or by referenced
requirements, the marine inspector shall clearly state the reasons which caused him to arrive at such
decisions.
(b) If the owner or his representative disagrees with a decision made by the marine inspector, he shall take up
the matter with the local Officer in Charge, Marine Inspection. The owner or his representative may appeal
the decision of the Officer in Charge, Marine Inspection, in accordance with § 50.20-40.

§ 50.20-40 Right of appeal.
Any person directly affected by a decision or action taken under this subchapter, by or on behalf of the Coast Guard,
may appeal therefrom in accordance with subpart 1.03 of this chapter.
[CGD 88-033, 54 FR 50380, Dec. 6, 1989]

Subpart 50.25—Acceptance of Material and Piping Components
§ 50.25-1 General.
Link to an amendment published at 89 FR 50094, June 12, 2024.
(a) Materials and piping components used in the construction of boilers, pressure vessels, pressure piping
systems, and related components are accepted by review of manufacturer or mill certificates under §
50.25-3 of this part, product marking in accordance with an adopted industry standard, or technical
information indicating their compliance with the requirements of this subchapter.
(b) Plate, bar stock, pipe, tube, pipe joining fittings (tees, elbows, reducers, etc.), bolting, castings, forgings,
and flanges, are accepted by review of manufacturer or mill certificates under §§ 50.25-3, 50.25-5, and
50.25-7 of this part.
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46 CFR 50.25-1(c)

(c) Valves, fluid conditioner fittings, and special purpose fittings complying with an adopted industry standard
and marked in accordance with the standard are accepted through review of the marking indicating
compliance with the adopted industry standard.
(d) Valves, fluid conditioner fittings, special purpose fittings, and pipe joining fittings not complying with an
adopted industry standard are accepted for use on a case-by-case basis. Acceptance is granted by the
Marine Safety Center or the Officer in Charge, Marine Inspection, having cognizance over the installation
of the product. To obtain acceptance of a product, the manufacturer must submit, via the vessel owner or
representative, the information described in § 50.25-10 of this part to the Marine Safety Center or the
cognizant Officer in Charge, Marine Inspection.
(e) Components designed for hydraulic service which require shock testing under § 58.30-15(f) of this
chapter and nonmetallic flexible hose assemblies must be accepted by the Commandant (CG-ENG).
Manufacturers desiring acceptance of these products must submit information necessary to show
compliance with §§ 56.60-25(c) or 58.30-15 of this chapter, as applicable. Acceptance of specific
installations of acceptable nonmetallic flexible hose assemblies and shock tested hydraulic components
is granted by the Marine Safety Center or the cognizant Officer in Charge, Marine Inspection, as described
in paragraph (d) of this section.
(f) The vessel owner or representative shall make available to the Officer in Charge, Marine Inspection, the
manufacturer or mill certificates, specific letters of acceptance, or approved plans necessary to verify that
piping components comply with the requirements of this subchapter.
[CGD 77-140, 54 FR 40598, Oct. 2, 1989, as amended by CGD 95-072, 60 FR 50462, Sept. 29, 1995; CGD 96-041, 61 FR 50727,
Sept. 27, 1996; USCG-2004-18884, 69 FR 58345, Sept. 30, 2004; USCG-2003-16630, 73 FR 65160, Oct. 31, 2008; USCG-2012-0832,
77 FR 59777, Oct. 1, 2012]

§ 50.25-3 Manufacturer or mill certification.
Link to an amendment published at 89 FR 50094, June 12, 2024.
(a) A manufacturer or mill producing materials used in certain products for installation on inspected vessels,
shall issue a certificate or mill test report which shall report the results of chemical analysis and
mechanical properties required by the ASTM specification.
(b) This certificate shall be made available to the marine inspector and Officer in Charge, Marine Inspection,
upon request to the fabricator. (For exception refer to § 50.25-5(d).)
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 77-140, 54 FR 40598, Oct. 2, 1989]

§ 50.25-5 Products requiring manufacturer or mill certification.
Link to an amendment published at 89 FR 50094, June 12, 2024.
(a) Products required to be certified by a manufacturer or by mill certificate shall be fabricated and tested in
accordance with the applicable specifications. Such products will not normally be subject to mill
inspection by the Coast Guard except as required by § 50.25-7.

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46 CFR 50.25-5(b)

(b) The Officer in Charge, Marine Inspection, having cognizance over the installation of the products required
to be certified shall ensure that adequate control has been exercised to identify the product with its
manufacturer or mill certificate.
(c) In the event that the Officer in Charge, Marine Inspection, determines that handling of a product has been
such that proper identification is not possible, he may:
(1) Require testing in his presence based on the applicable material or fabrication specification; or
(2) Reject the product on the basis that it cannot be properly identified.
(d) A product conforming to an acceptable material specification may, at the discretion of the Officer in
Charge, Marine Inspection, be accepted without referring to its manufacturer or mill certification, if:
(1) The product is marked in accordance with the identification marking requirements of the
specification;
(2) The marking alone is sufficient to identify that specification; and
(3) In the opinion of the Officer in Charge, Marine Inspection, the application of the product does not
require knowledge of the exact chemical analysis or mechanical properties enumerated on the
manufacturer or mill certificate.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 77-140, 54 FR 40598, Oct. 2, 1989]

§ 50.25-7 Testing of products required to be certified in presence of marine inspector.
Link to an amendment published at 89 FR 50094, June 12, 2024.
(a) Certified products are not normally tested in the presence of a marine inspector. The Commandant may,
however, assign a marine inspector to witness tests required by the applicable specifications to satisfy
himself that the requirements are met.
(b) Marine inspectors shall have free entry at all times to those parts of the plant where material subject to
the regulations in this subchapter is being manufactured. The manufacturer shall provide marine
inspectors all reasonable facilities to satisfy them that the material is being manufactured in accordance
with the requirements of the Commandant.
(c) Unless otherwise authorized, required tests and inspections described in applicable specifications shall
be made at the place of manufacture prior to shipment. Unless otherwise specified, tests shall be
performed at room temperature. These tests when performed in the presence of a marine inspector will
be so conducted as not to interfere unnecessarily with the operation of the plant.
(d) Marine inspectors shall assure themselves that test specimens are marked for positive identification with
the materials which they represent.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 77-140, 54 FR 40599, Oct. 2, 1989]

§ 50.25-10 Acceptance of piping components by specific letter or approved plan.
(a) A manufacturer of a piping component which does not comply with an adopted industry standard and
requires acceptance by specific letter or approved plan must do the following:
46 CFR 50.25-10(a) (enhanced display)

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46 CFR 50.25-10(a)(1)

(1) Submit an engineering type catalog or representative drawings of the component which includes the
pressure and temperature ratings of the component and identify the service for which it is intended.
(2) Identify materials used to fabricate the component. Materials must meet the requirements of
subpart 56.60 of this chapter. If the component is not manufactured to accepted material
specifications, the manufacturer must prove equivalency to accepted material specifications by
comparing details of the materials' chemical composition, mechanical properties, method of
manufacture, and complete chemical and mechanical test results with an accepted material
specification.
(3) Identify the industry standard, if any, to which the component is manufactured.
(4) Submit a description of nondestructive testing performed on the component.
(5) Submit a description of the marking applied to the component.
(6) Submit information showing compliance with the requirements of part 56, subparts 56.15, 56.20,
56.25, 56.30, or 56.35 of this chapter, as applicable.
(7) Submit any additional information necessary to evaluate the component's acceptability for its
intended application.
(b) If the component is found to comply with the requirements of this subchapter, the component is
designated as acceptable for its intended installation. This acceptance is in the form of a specific letter
relating directly to the particular component or in the form of an approved piping system plan in which the
component is identified as an integral part.
[CGD 77-140, 54 FR 40599, Oct. 2, 1989]

Subpart 50.30—Fabrication Inspection
Link to an amendment published at 89 FR 50095, June 12, 2024.
§ 50.30-1 Scope.
(a) The manufacturer shall notify the Officer in Charge, Marine Inspection, of the intended fabrication of
pressure vessels that will require Coast Guard inspection.
(b) For exemption of certain pressure vessels from shop inspection see § 54.01-15 of this subchapter.
(c) For a classification delineation of boilers and pressure vessels refer to tables 54.01-5(a) and 54.01-5(b) of
this subchapter.
[CGFR 68-82, 33 FR 18808, Dec. 18, 1968, as amended by CGD 81-79, 50 FR 9431, Mar. 8, 1985]

§ 50.30-10 Class I, I-L and II-L pressure vessels.
(a) Classes I, I-L and II-L pressure vessels shall be subject to shop inspection at the plant where they are
being fabricated, or when determined necessary by the Officer in Charge, Marine Inspection.
(b) The manufacturer shall submit Class I, I-L and II-L pressure vessels, as defined in parts 54 and 56 of this
subchapter for shop inspection at such stages of fabrication as may be requested by the Officer in
Charge, Marine Inspection.
46 CFR 50.30-10(b) (enhanced display)

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46 CFR 50.30-15

[CGD 95-012, 60 FR 48049, Sept. 18, 1995]

§ 50.30-15 Class II pressure vessels.
(a) Class II pressure vessels shall be subject to shop inspections at the plant where they are being fabricated,
as or when determined necessary by the Officer in Charge, Marine Inspection. The inspections described
in this section are required, unless specifically exempted by other regulations in this subchapter.
(b) The first inspection of Class II welded pressure vessels shall be performed during the welding of the
longitudinal joint. At this time the marine inspector shall check the material and fit-up of the work, and
ascertain that only welders who have passed the required tests are employed.
(c) A second inspection of Class II welded pressure vessels shall be made during the welding of the
circumferential joints. At this time the marine inspector shall check any new material being used which
may not have been examined at the time of the first inspection, also the fit-up of the vessel at this stage of
fabrication, and in addition, observe the welding and ascertain that only welders who have passed the
required tests are employed.

§ 50.30-20 Class III pressure vessels.
(a) Class III pressure vessels shall be subject to shop inspection at the plant where they are being fabricated,
as or when determined necessary by the Officer in Charge, Marine Inspection. The inspection described in
this section is required, unless specifically exempted by other regulations in this subchapter.
(b) For Class III welded pressure vessels, one inspection shall be made during the welding of the longitudinal
joint. If there is no longitudinal joint, the inspection shall be made during the welding of a circumferential
joint. At this time the marine inspector shall check the material and fit-up of the work and see that only
welders who have passed the required tests are employed.

46 CFR 50.30-20(b) (enhanced display)

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