Download:
pdf |
pdf46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR Part 154 (June 3, 2024)
This content is from the eCFR and is authoritative but unofficial.
Title 46 —Shipping
Chapter I —Coast Guard, Department of Homeland Security
Subchapter O —Certain Bulk Dangerous Cargoes
Part 154 Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
Subpart A
General
§ 154.1 Incorporation by reference.
§ 154.3 Purpose.
§ 154.5 Applicability.
§ 154.7 Definitions, acronyms, and terms.
§ 154.9 Issuance of documents.
§ 154.12 Existing gas vessel: Endorsements and requirements.
§ 154.15 U.S. flag vessel: Endorsement application.
§ 154.17 U.S. flag vessel: Certificate of Inspection endorsement.
§ 154.19 U.S. flag vessel: IMO certificate issuance.
§ 154.22 Foreign flag vessel: Certificate of Compliance endorsement application.
§ 154.24 Foreign flag vessel: IMO Certificate.
§ 154.30 [Reserved]
§ 154.32 Equivalents.
§ 154.34 Special approval: Requests.
§ 154.36 Correspondence and vessel information: Submission.
§ 154.40 Right of appeal.
Subpart B
Inspections and Tests
Examination Requirements for Foreign Flag Vessels
§ 154.150 Examination required for a Certificate of Compliance.
§ 154.151 Procedures for having the Coast Guard examine a vessel for a Certificate of
Compliance.
Subpart C
Design, Construction and Equipment
Hull Structure
§ 154.170 Outer hull steel plating.
§ 154.172 Contiguous steel hull structure.
§ 154.174 Transverse contiguous hull structure.
§ 154.176 Longitudinal contiguous hull structure.
§ 154.178 Contiguous hull structure: Heating system.
§ 154.180 Contiguous hull structure: Welding procedure.
§ 154.182 Contiguous hull structure: Production weld test.
§ 154.188 Membrane tank: Inner hull steel.
46 CFR Part 154 (June 3, 2024) (enhanced display)
page 1 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR Part 154 (June 3, 2024)
§ 154.195 Aluminum cargo tank: Steel enclosure.
Ship Survival Capability and Cargo Tank Location
§ 154.200 Stability requirements: General.
§ 154.235 Cargo tank location.
Ship Arrangements
§ 154.300 Segregation of hold spaces from other spaces.
§ 154.305 Segregation of hold spaces from the sea.
§ 154.310 Cargo piping systems.
§ 154.315 Cargo pump and cargo compressor rooms.
§ 154.320 Cargo control stations.
§ 154.325 Accommodation, service, and control spaces.
§ 154.330 Openings to accommodation, service, or control spaces.
§ 154.340 Access to tanks and spaces in the cargo area.
§ 154.345 Air locks.
§ 154.350 Bilge and ballast systems in the cargo area.
§ 154.355 Bow and stern loading piping.
§ 154.356 Cargo emergency jettisoning piping.
Cargo Containment Systems
§ 154.401 Definitions.
§ 154.405 Design vapor pressure (Po) of a cargo tank.
§ 154.406 Design loads for cargo tanks and fixtures: General.
§ 154.407 Cargo tank internal pressure head.
§ 154.408 Cargo tank external pressure load.
§ 154.409 Dynamic loads from vessel motion.
§ 154.410 Cargo tank sloshing loads.
§ 154.411 Cargo tank thermal loads.
§ 154.412 Cargo tank corrosion allowance.
Integral Tanks
§ 154.418 General.
§ 154.419 Design vapor pressure.
§ 154.420 Tank design.
§ 154.421 Allowable stress.
Membrane Tanks
§ 154.425 General.
§ 154.426 Design vapor pressure.
§ 154.427 Membrane tank system design.
§ 154.428 Allowable stress.
§ 154.429 Calculations.
§ 154.430 Material test.
46 CFR Part 154 (June 3, 2024) (enhanced display)
page 2 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR Part 154 (June 3, 2024)
§ 154.431 Model test.
§ 154.432 Expansion and contraction.
Semi-Membrane Tanks
§ 154.435 General.
§ 154.436 Design vapor pressure.
Independent Tank Type A
§ 154.437 General.
§ 154.438 Design vapor pressure.
§ 154.439 Tank design.
§ 154.440 Allowable stress.
Independent Tank Type B
§ 154.444 General.
§ 154.445 Design vapor pressure.
§ 154.446 Tank design.
§ 154.447 Allowable stress.
§ 154.448 Calculations.
§ 154.449 Model test.
Independent Tank Type C and Process Pressure Vessels
§ 154.450 General.
§ 154.451 Design vapor pressure.
§ 154.452 External pressure.
§ 154.453 Failure to meet independent tank type C standards.
Secondary Barrier
§ 154.459 General.
§ 154.460 Design criteria.
Insulation
§ 154.465 General.
§ 154.466 Design criteria.
§ 154.467 Submission of insulation information.
Support System
§ 154.470 General.
§ 154.471 Design criteria.
§ 154.476 Cargo transfer devices and means.
Cargo and Process Piping Systems
§ 154.500 Cargo and process piping standards.
§ 154.503 Piping and piping system components: Protection from movement.
§ 154.506 Mechanical expansion joint: Limits in a piping system.
§ 154.512 Piping: Thermal isolation.
§ 154.514 Piping: Electrical bonding.
46 CFR Part 154 (June 3, 2024) (enhanced display)
page 3 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR Part 154 (June 3, 2024)
§ 154.516 Piping: Hull protection.
§ 154.517 Piping: Liquid pressure relief.
§ 154.519 Piping relief valves.
§ 154.520 Piping calculations.
§ 154.522 Materials for piping.
§ 154.524 Piping joints: Welded and screwed couplings.
§ 154.526 Piping joints: Flange connection.
§ 154.528 Piping joints: Flange type.
§ 154.530 Valves: Cargo tank MARVS 69 kPa gauge (10 psig) or lower.
§ 154.532 Valves: Cargo tank MARVS greater than 69 kPa gauge (10 psig).
§ 154.534 Cargo pumps and cargo compressors.
§ 154.536 Cargo tank gauging and measuring connections.
§ 154.538 Cargo transfer connection.
§ 154.540 Quick-closing shut-off valves: Emergency shut-down system.
§ 154.544 Quick-closing shut-off valves.
§ 154.546 Excess flow valve: Closing flow.
§ 154.548 Cargo piping: Flow capacity.
§ 154.550 Excess flow valve: Bypass.
Cargo Hose
§ 154.551 Cargo hose: General.
§ 154.552 Cargo hose: Compatibility.
§ 154.554 Cargo hose: Bursting pressure.
§ 154.556 Cargo hose: Maximum working pressure.
§ 154.558 Cargo hose: Marking.
§ 154.560 Cargo hose: Prototype test.
§ 154.562 Cargo hose: Hydrostatic test.
Materials
§ 154.605 Toughness test.
§ 154.610 Design temperature not colder than 0 °C (32 °F).
§ 154.615 Design temperature below 0 °C (32 °F) and down to −55 °C (−67 °F).
§ 154.620 Design temperature below −55 °C (−67 °F) and down to −165 °C (−265 °F).
§ 154.625 Design temperature below 0 °C (32 °F) and down to −165 °C (−265 °F).
§ 154.630 Cargo tank material.
Construction
§ 154.650 Cargo tank and process pressure vessel welding.
§ 154.655 Stress relief for independent tanks type C.
§ 154.660 Pipe welding.
§ 154.665 Welding procedures.
Cargo Pressure and Temperature Control
46 CFR Part 154 (June 3, 2024) (enhanced display)
page 4 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR Part 154 (June 3, 2024)
§ 154.701 Cargo pressure and temperature control: General.
§ 154.702 Refrigerated carriage.
§ 154.703 Methane (LNG).
§ 154.705 Cargo boil-off as fuel: General.
§ 154.706 Cargo boil-off as fuel: Fuel lines.
§ 154.707 Cargo boil-off as fuel: Ventilation.
§ 154.708 Cargo boil-off as fuel: Valves.
§ 154.709 Cargo boil-off as fuel: Gas detection equipment.
Cargo Vent Systems
§ 154.801 Pressure relief systems.
§ 154.802 Alternate pressure relief settings.
§ 154.804 Vacuum protection.
§ 154.805 Vent masts.
§ 154.806 Capacity of pressure relief valves.
Atmospheric Control in Cargo Containment Systems
§ 154.901 Atmospheric control within cargo tanks and cargo piping systems.
§ 154.902 Atmospheric control within hold and interbarrier spaces.
§ 154.903 Inert gas systems: General.
§ 154.904 Inert gas system: Controls.
§ 154.906 Inert gas generators.
§ 154.908 Inert gas generator: Location.
§ 154.910 Inert gas piping: Location.
§ 154.912 Inerted spaces: Relief devices.
Electrical
§ 154.1000 Applicability.
§ 154.1002 Definition.
§ 154.1005 Equipment approval.
§ 154.1010 Electrical equipment in gas-dangerous space or zone.
§ 154.1015 Lighting in gas-dangerous space.
§ 154.1020 Emergency power.
Firefighting
§ 154.1105 Exterior water spray system: General.
§ 154.1110 Areas protected by system.
§ 154.1115 Discharge.
§ 154.1120 Nozzles.
§ 154.1125 Pipes, fittings, and valves.
§ 154.1130 Sections.
§ 154.1135 Pumps.
Firefighting System: Dry Chemical
46 CFR Part 154 (June 3, 2024) (enhanced display)
page 5 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR Part 154 (June 3, 2024)
§ 154.1140 Dry chemical system: General.
§ 154.1145 Dry chemical supply.
§ 154.1150 Distribution of dry chemical.
§ 154.1155 Hand hose line: Coverage.
§ 154.1160 Monitor coverage of system.
§ 154.1165 Controls.
§ 154.1170 Hand hose line: General.
Cargo Area: Mechanical Ventilation System
§ 154.1200 Mechanical ventilation system: General.
§ 154.1205 Mechanical ventilation system: Standards.
§ 154.1210 Hold space, void space, cofferdam, and spaces containing cargo piping.
Instrumentation
§ 154.1300 Liquid level gauging system: General.
§ 154.1305 Liquid level gauging system: Standards.
§ 154.1310 Closed gauge shut-off valve.
§ 154.1315 Restricted gauge excess flow valve.
§ 154.1320 Sighting ports, tubular gauge glasses, and flat plate type gauge glasses.
§ 154.1325 Liquid level alarm system: All cargo tanks.
§ 154.1330 Liquid level alarm system: Independent tank type C.
§ 154.1335 Pressure and vacuum protection.
§ 154.1340 Temperature measuring devices.
§ 154.1345 Gas detection.
§ 154.1350 Flammable gas detection system.
§ 154.1360 Oxygen analyzer.
§ 154.1365 Audible and visual alarms.
§ 154.1370 Pressure gauge and vacuum gauge marking.
§ 154.1375 Readout for temperature measuring device: Marking.
Safety Equipment
§ 154.1400 Safety equipment: All vessels.
§ 154.1405 Respiratory protection.
§ 154.1410 Decontamination shower.
§ 154.1415 Air compressor.
§ 154.1420 Stretchers and equipment.
§ 154.1430 Equipment locker.
§ 154.1435 Medical first aid guide.
§ 154.1440 Antidotes.
Subpart D
Special Design and Operating Requirements
§ 154.1700 Purpose.
§ 154.1702 Materials of construction.
46 CFR Part 154 (June 3, 2024) (enhanced display)
page 6 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
§ 154.1705
§ 154.1710
§ 154.1715
§ 154.1720
§ 154.1725
§ 154.1730
§ 154.1735
§ 154.1740
§ 154.1745
§ 154.1750
§ 154.1755
§ 154.1760
Subpart E
§ 154.1800
§ 154.1801
§ 154.1802
§ 154.1803
§ 154.1804
§ 154.1806
§ 154.1808
§ 154.1809
§ 154.1810
§ 154.1812
§ 154.1814
§ 154.1816
§ 154.1818
§ 154.1820
§ 154.1822
§ 154.1824
§ 154.1826
§ 154.1828
§ 154.1830
§ 154.1831
§ 154.1834
§ 154.1836
§ 154.1838
§ 154.1840
§ 154.1842
§ 154.1844
46 CFR Part 154 (June 3, 2024)
Independent tank type C.
Exclusion of air from cargo tank vapor spaces.
Moisture control.
Indirect refrigeration.
Ethylene oxide.
Ethylene oxide: Loading and off loading.
Methyl acetylene-propadiene mixture.
Vinyl chloride: Inhibiting and inerting.
Vinyl chloride: Transferring operations.
Butadiene or vinyl chloride: Refrigeration system.
Nitrogen.
Liquid ammonia.
Operations
Special operating requirements under Part 35 of this chapter.
Certificates, letters, and endorsements: U.S. flag vessels.
Certificates, letters and endorsements: Foreign flag vessels.
Expiration of Certificates of Compliance.
Document posted in wheelhouse.
Regulations on board.
Limitations in the endorsement.
Loading and stability manual.
Cargo manual.
Operational information for terminal personnel.
Cargo information cards.
Cargo location plan.
Certification of inhibition.
Shipping document.
Shipping document: Copy for transfer terminal.
Obstruction of pumproom ladderways.
Opening of cargo tanks and cargo sampling.
Spaces containing cargo vapor: Entry.
Warning sign.
Persons in charge of transferring liquid cargo in bulk or preparing cargo tanks.
Cargo transfer piping.
Vapor venting as a means of cargo tank pressure and temperature control.
Discharge by gas pressurization.
Protective clothing.
Cargo system: Controls and alarms.
Cargo tanks: Filling limits.
46 CFR Part 154 (June 3, 2024) (enhanced display)
page 7 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
§ 154.1846
§ 154.1848
§ 154.1850
§ 154.1852
§ 154.1854
§ 154.1858
§ 154.1860
§ 154.1862
§ 154.1864
§ 154.1866
§ 154.1868
§ 154.1870
§ 154.1872
46 CFR Part 154 (June 3, 2024)
Relief valves: Changing set pressure.
Inerting.
Entering cargo handling spaces.
Air breathing equipment.
Methane (LNG) as fuel.
Cargo hose.
Integral tanks: Cargo colder than −10 °C (14 °F).
Posting of speed reduction.
Vessel speed within speed reduction.
Cargo hose connection: Transferring cargo.
Portable blowers in personnel access openings.
Bow and stern loading.
Cargo emergency jettisoning.
Appendix A to Part 154
Equivalent Stress
Appendix B to Part 154
Stress Analyses Definitions
PART 154—SAFETY STANDARDS FOR SELF-PROPELLED VESSELS
CARRYING BULK LIQUEFIED GASES
Authority: 46 U.S.C. 3703, 9101; Department of Homeland Security Delegation No. 0170.1.
Source: CGD 74-289, 44 FR 26009, May 3, 1979, unless otherwise noted.
Editorial Note: Nomenclature changes to part 154 appear part 154 appear by CGD-95-072, 60 FR 50466, Sept.
29, 1995, CGD-96-041, 61 FR 50732, Sept. 27, 1996, USCG-2009-0702, 74 FR 49235, Sept. 25, 2009, and
USCG-2012-0832, 77 FR 59785, Oct. 1, 2012.
Subpart A—General
Source: CGD 77-069, 52 FR 31626, Aug. 21, 1987, unless otherwise noted.
§ 154.1 Incorporation by reference.
(a) Certain materials are incorporated by reference into this part with approval of the Director of the Federal
Register in accordance with 5 U.S.C. 552(a). The Office of the Federal Register publishes a list “Material
Approved for Incorporation by Reference,” which appears in the Finding Aids section of this volume. To
enforce any edition other than the one listed in paragraph (b) of this section, notice of change must be
published in the FEDERAL REGISTER and the material made available. All approved material is on file at the
Coast Guard Headquarters. Contact Commandant (CG-ENG), Attn: Office of Design and Engineering
46 CFR 154.1(a) (enhanced display)
page 8 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.1(b)
Systems, U.S. Coast Guard Stop 7509, 2703 Martin Luther King Jr. Avenue SE., Washington, DC
20593-7509; or contact the National Archives and Records Administration (NARA). For information on the
availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/
code_of_federal_regulations/ibr_locations.html.
(b) The materials approved for incorporation by reference in this part are:
American Bureau of Shipping (ABS)
ABS Plaza, 16855 Northchase Drive, Houston, TX 77060
Rules for Building and Classing Steel Vessels, 1981
American National Standards Institute
11 West 42nd Street, New York, NY 10036
ANSI Z89.1-69 Safety Requirements for Industrial Head Protection, 1969
ANSI Z87.1-79 Practice for Occupational and Educational Eye and Face Protection, 1979
American Society for Testing and Materials (ASTM)
100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.
ASTM A 20/A 20M-97a, Standard Specification for General Requirements for Steel Plates for Pressure
Vessels—154.610
ASTM F 1014-92, Standard Specification for Flashlights on Vessels—154.1400
Note: All other documents referenced in this part are still in effect.
International Maritime Organization
Publications Section, 4 Albert Embankment, London SE1 7SR, United Kingdom
Resolution A.328(IX), Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk, 1976
Code For Existing Ships Carrying Liquefied Gases in Bulk, 1976
Medical First Aid Guide for Use in Accidents Involving Dangerous Goods
Underwriters Laboratories, Inc.
12 Laboratory Drive, Research Triangle Park, NC 27709-3995
46 CFR 154.1(b) (enhanced display)
page 9 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.3
UL No. 783-79 Standard for Safety, Electric Flashlights for Use in Hazardous Locations, Class 1, Groups C and
D, 1979.
[CGD 77-069, 52 FR 31626, Aug. 21, 1987, as amended by CGD 82-042, 53 FR 17705, May 18, 1988; CGD 82-042, 53 FR 18949,
May 25, 1988; CGD 88-070, 53 FR 34535, Sept. 7, 1988; CGD 96-041, 61 FR 50732, Sept. 27, 1996; CGD 97-057, 62 FR 51048, Sept.
30, 1997; USCG-1999-5151, 64 FR 67183, Dec. 1, 1999; USCG-2000-7790, 65 FR 58463, Sept. 29, 2000; 69 FR 18803, Apr. 9, 2004;
USCG-2013-0671, 78 FR 60155, Sept. 30, 2013]
§ 154.3 Purpose.
The purpose of this part is to prescribe rules for new and existing gas vessels.
§ 154.5 Applicability.
This part applies to each self-propelled vessel that has on board bulk liquefied gases as cargo, cargo residue or
vapor, except subpart C does not apply if the vessel meets § 154.12 (b), (c), or (d).
§ 154.7 Definitions, acronyms, and terms.
As used in this part:
“A” Class Division means a division as defined in Regulation 3 of Chapter II-2 of the 1974 Safety Convention.
Accommodation spaces means public spaces, corridors, lavatories, cabins, offices, hospitals, cinemas, game
and hobby rooms, pantries containing no cooking appliances, and spaces used in a similar fashion.
Boiling point means the temperature at which a substance's vapor pressure is equal to the atmospheric
barometric pressure.
Breadth (B) means the maximum width of the vessel in meters measured amidships to the molded line of the
frame in a ship with a metal shell and to the outer surface of the hull in a ship with a shell of any other
material.
Cargo area means that part of the vessel that contains the cargo containment system, cargo pump rooms,
cargo compressor rooms, and the deck areas over the full beam and the length of the vessel above them,
but does not include the cofferdams, ballast spaces, or void spaces at the after end of the aftermost hold
space or the forward end of the forwardmost hold space.
Cargo containment system means the arrangement for containment of the cargo including a primary and
secondary barrier, associated insulation and any intervening spaces, and adjacent structure that is
necessary for the support of these elements.
Cargo service space means space within the cargo area that is more than 2 m2 (21.5 ft.2) in deck area and used
for work shops, lockers, or store rooms.
Cargo tank means the liquid tight shell that is the primary container of the cargo.
Certificate of Compliance means a certificate issued by the Coast Guard to a foreign flag vessel after it is
examined and found to comply with regulations in this chapter.
Cofferdam means the isolating space between two adjacent steel bulkheads or decks, which could be a void
space or a ballast space.
46 CFR 154.7 “Cofferdam” (enhanced display)
page 10 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.7 “Contiguous hull structure”
Contiguous hull structure includes the inner deck, the inner bottom plating, longitudinal bulkhead plating,
transverse bulkhead plating, floors, webs, stringers, and attached stiffeners.
Control space means those spaces in which the vessel's radio, main navigating equipment, or the emergency
source of power is located or in which the fire control equipment, other than firefighting control equipment
under § 154.1140 to § 154.1170, is centralized.
Design temperature means the minimum cargo temperature the Coast Guard allows for loading, unloading, or
carriage.
Design vapor pressure (Po) means the maximum gauge pressure at the top of the cargo tank for the design of
the cargo tank.
Document means a Certificate of Inspection for a U.S. flag vessel or a Certificate of Compliance for a foreign
flag vessel.
Existing gas vessel means a self-propelled vessel that—
(a) Is delivered on or before October 31, 1976; or
(b) Is delivered between October 31, 1976 and June 30, 1980, and is not a new gas vessel.
Flammable cargoes includes the following liquefied gases from Table 4 (follows § 154.1872):
Acetaldehyde
Butadiene
Butane
Butylene
Dimethylamine
Ethane
Ethylamine
Ethyl chloride
Ethylene
Ethylene oxide
Methane (LNG)
Methyl acetylene-propadiene mixture
Methyl bromide
Methyl chloride
46 CFR 154.7 “Flammable cargoes” (enhanced display)
page 11 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.7 “Gas-dangerous space”
Propane
Propylene
Vinyl chloride
Gas-dangerous space includes the following spaces:
(a) A space in the cargo area without arrangements to provide a safe atmosphere at all times.
(b) An enclosed space outside the cargo area through which any piping that may contain liquid or
gaseous cargo passes, or within which that piping terminates, without arrangements to prevent gas
from escaping into the space.
(c) A cargo containment system and cargo piping.
(d) A hold space where cargo is carried in a cargo containment system:
(1) With a secondary barrier; or
(2) Without a secondary barrier.
(e) A space separated from a hold space under paragraph (d)(1) of this definition by a single gastight
boundary.
(f) A cargo pumproom and a cargo compressor room.
(g) A zone on the weather deck or a semi-enclosed space on the weather deck within 3.05 m (10 ft) of
any cargo tank outlet, gas or vapor outlet, cargo pipe flange, cargo valve, or of entrances and
ventilation openings to a cargo pump room or a cargo compressor room.
(h) Except for existing gas vessels, the weather deck over the cargo area and 3.05 m (10 ft) forward and
aft of the cargo area on the weather deck to 2.4 m (8 ft) above the weather deck.
(i)
A zone within 2.4 m (8 ft) of the outer surface of a cargo containment system where the surface is
exposed to the weather.
(j)
An enclosed or semi-enclosed space in which there is piping containing cargo, except those—
(1) With gas sampling lines for gas detection equipment under § 154.1350(n); or
(2) In which boil-off gas is used as fuel under § 154.703.
(k) A space for storage of cargo hoses.
(l)
An enclosed or semi-enclosed space having an opening into any gas-dangerous space or zone.
Gas-safe space means a space that is not a gas-dangerous space.
Hold space means the space enclosed by the vessel's structure in which there is a cargo containment system.
IMO stands for the lnternational Maritime Organization.
IMO Certificate means a Certificate of Fitness for the Carriage of Liquefied Gases in Bulk issued under the IMO—
(a) “Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk”, adopted
November 12, 1975 by Assembly Resolution A.328(IX), as amended;
46 CFR 154.7 “IMO Certificate” (a) (enhanced display)
page 12 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.7 “IMO Certificate” (b)
(b) “Code for Existing Ships Carrying Liquefied Gases in Bulk”, adopted November 12, 1975, as amended;
or
(c) “Recommendations Concerning Ships Not Covered by the Code for the Construction and Equipment
of Ships Carrying Liquefied Gases in Bulk”, (Resolution A.328(IX)), adopted November 12, 1975 by
Assembly Resolution A.329(IX).
Independent tank is a cargo tank that is permanently affixed to the vessel, is self-supporting, and is not part of
the hull or essential to the strength or integrity of the hull.
Independent tank type A is an independent cargo tank designed primarily using classification society classical
ship structural analysis procedures.
Independent tank type B is an independent cargo tank designed from model tests, refined analytical tools, and
analysis methods to determine stress levels, fatigue life, and crack propagation characteristics.
Independent tank type C (pressure tank) is an independent cargo tank meeting pressure vessel criteria where the
dominant stress producing load is design vapor pressure.
Insulation space means a space, that could be an interbarrier space, occupied wholly or in part by insulation.
Integral tank means a cargo tank that is a structural part of the vessel's hull and is influenced in the same
manner and by the same loads that stress the adjacent hull structure.
Interbarrier space means the space between a primary and a secondary barrier, with or without insulation or
other material.
Length (L) is ninety-six percent of the total length in meters on a waterline at eighty-five percent of the least
molded depth measured from the top of the keel or the length from the foreside of the stem to the axis of
the rudder stock on the waterline, whichever is greater. In vessels having a rake of keel, the waterline is
parallel to the design waterline.
Liquefied gas means a cargo having a vapor pressure of 172 kPa (25 psia) or more at 37.8 °C (100 °F).
MARVS stands for the Maximum Allowable Relief Valve Setting.
Membrane tank is a cargo tank that is not self-supporting and consists of a thin layer (membrane) supported
through insulation by the adjacent hull structure.
New gas vessel means a self-propelled vessel that—
(a) Is constructed under a building contract awarded after October 31, 1976;
(b) In the absence of a building contract, has a keel laid or is at a similar stage of construction after
December 31, 1976;
(c) Is delivered after June 30, 1980; or
(d) Has undergone a major conversion for which—
(1) The building contract is awarded after October 31, 1976;
(2) In the absence of a building contract, conversion is begun after December 31, 1976; or
(3) Conversion is completed after June 30, 1980.
Primary barrier means the inner boundary that contains the cargo when the cargo containment system includes
two boundaries.
46 CFR 154.7 “Primary barrier” (enhanced display)
page 13 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.7 “Process pressure vessel”
Process pressure vessel means a pressure vessel that is used in a reliquefaction, cargo heating, or other system
that processes cargo.
Remote group alarm means an audible and visual alarm that alerts when an alarm condition exists but does not
identify that condition.
Secondary barrier means the liquid resisting outer boundary of a cargo containment system when the cargo
containment system includes two boundaries.
Semi-membrane tank is a cargo tank that is not self-supporting and that can expand and contract due to
thermal, hydrostatic, and pressure loadings. It consists of flat surfaces, supported through insulation by
the adjacent hull structure, and shaped corners that connect the flat surfaces.
Service space means a space outside the cargo area that is used for a galley, pantry containing cooking
appliances, locker or store room, workshop except those in machinery spaces, and similar spaces and
trunks to those spaces.
Shut-off valve is a valve that closes a pipeline and provides nominal metal to metal contact between the valve
operating parts, including the disc and gate, and the valve body.
Specific gravity (p) means the ratio of the density of the cargo at the design temperature to the density of water
at 4 °C (39 °F).
Tank cover is the structure protecting those parts of the cargo containment system that protrude through the
weather deck and providing continuity to the deck structure.
Tank dome means the uppermost portion of the cargo tank. For below deck cargo containment systems, it
means the uppermost portion of the cargo tank that protrudes through the weather deck or through the
tank cover.
Toxic cargoes includes the following liquefied gases from Table 4 (follows § 154.1872):
Acetaldehyde
Ammonia, anhydrous
Dimethylamine
Ethylamine
Ethyl chloride
Ethylene oxide
Methyl bromide
Methyl chloride
Sulfur dioxide
Vinyl chloride
46 CFR 154.7 “Toxic cargoes” (enhanced display)
page 14 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.7 “Vapor pressure”
Vapor pressure means the absolute equilibrium pressure of the saturated vapor above the liquid, expressed in
kPa (psia), at a specific temperature.
Void space means an enclosed space in the cargo area outside of the cargo containment system, except a hold
space, ballast space, fuel oil tank, cargo pump or compressor room, or any space used by personnel.
1974 Safety Convention stands for the International Convention on Safety of Life at Sea, 1974, done at London,
November 1, 1974.
§ 154.9 Issuance of documents.
The Coast Guard issues an endorsed Certificate of Inspection to a U.S. flag vessel or an endorsed Certificate of
Compliance to a foreign flag vessel that meets this part.
§ 154.12 Existing gas vessel: Endorsements and requirements.
(a) Except an existing gas vessel under paragraph (b), (c), or (d) of this section, an existing gas vessel must
meet subpart C of this part if the owner desires a document endorsed for the carriage of a cargo listed in
Table 4 (follows § 154.1872).
(b) If an existing gas vessel is issued a document by the Coast Guard before November 1, 1987 that is
endorsed for the carriage of a cargo listed in Table 4 (follows § 154.1872), and the owner desires the
same endorsement on a reissued document, the vessel must—
(1) Continue to meet the same design and construction standards under which the Coast Guard issued
the original document; and
(2) Meet paragraph (e) of this section.
(c) If an existing gas vessel is issued a document by the Coast Guard before November 1, 1987 that is
endorsed for the carriage of a cargo listed in Table 4 (follows § 154.1872), and the owner desires an
endorsement for a different cargo listed in that table, the vessel must—
(1) Continue to meet the same design and construction standards under which the Coast Guard issued
the original document;
(2) Meet paragraph (e) of this section;
(3) Meet subpart D for the different cargo; and
(4) Meet any additional requirements of this part that the Commandant (CG-ENG) determines to be
necessary for safety.
(d) If an existing gas vessel does not meet paragraph (b) or (c) of this section and the owner desires a
document endorsed for the carriage of a cargo listed in Table 4 (follows § 154.1872), the vessel must—
(1) Have a letter from the Coast Guard dated before November 1, 1987 stating that—
(i)
Review of the vessel's plans for the carriage of that cargo is completed; or
(ii) The vessel's IMO Certificate endorsed for the carriage of that cargo is accepted;
(2) Meet the plans that were reviewed and marked “Examined” or “Approved” by the Coast Guard, or
meet the standards under which the IMO Certificate was issued;
(3) Meet paragraph (e) of this section; and
46 CFR 154.12(d)(3) (enhanced display)
page 15 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.12(d)(4)
(4) Meet any additional requirements of this part that the Commandant (CG-ENG) determines to be
necessary for safety.
(e) If the owner of a vessel desires any document endorsement described in paragraph (b), (c), or (d) of this
section, the existing gas vessel must meet the requirements in each of the following:
(1) Section 154.310 (d) and (e).
(2) Section 154.320 (b) and (c).
(3) Section 154.330 (a) through (e).
(4) Section 154.340(d).
(5) Section 154.345 (a), (b)(1) through (b)(5), (b)(7) and (c).
(6) Section 154.476(a).
(7) Section 154.519(a)(2).
(8) Section 154.534.
(9) Section 154.538.
(10) Section 154.540 (c) and (d).
(11) Section 154.556.
(12) Section 154.558.
(13) Section 154.560.
(14) Section 154.562.
(15) Section 154.703.
(16) Section 154.705.
(17) Section 154.706.
(18) Section 154.707.
(19) Section 154.708.
(20) Section 154.709.
(21) Section 154.904.
(22) Section 154.906.
(23) Section 154.908(a), unless the space is separated from the accommodation, service, or control
space by a steel door that—
(i)
Is watertight when tested with a firehose at not less than 207 kPa gauge (30 psig);
(ii) Has a means to self-close and does not have latches or other devices designed to hold it open;
and
(iii) Has an audible and visual alarm on both sides of the door which is actuated when the door is
open.
46 CFR 154.12(e)(23)(iii) (enhanced display)
page 16 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.12(e)(24)
(24) Section 154.910.
(25) Section 154.912.
(26) Sections 154.1110 through 154.1130, except §§ 154.1115(b), 154.1120(b), and 154.1125 (c) and (f).
(27) Section 154.1145, except an existing gas vessel with a cargo carrying capacity of less than 2500 m3
(88,200 ft3) may have only one self-contained dry chemical storage unit if that unit—
(i)
is installed before November 1, 1987; and
(ii) Has the capacity to meet § 154.1145 (d) and (e), and § 154.1170(e).
(28) Section 154.1150 (a) and (b).
(29) Section 154.1155.
(30) Section 154.1160.
(31) Section 154.1165 (a), (b), (d), and (f).
(32) Section 154.1170 (b) through (f).
(33) Section 154.1200 (a), (b)(1), and (b)(2).
(34) Section 154.1205(f).
(35) Section 154.1325.
(36) Section 154.1335(e).
(37) Section 154.1350 (e), (f), (i), (o), and (u).
§ 154.15 U.S. flag vessel: Endorsement application.
(a) A person who desires the endorsement required under § 154.1801 for a U.S. flag vessel must submit an
application for an endorsement of the vessel's Subchapter D Certificate of Inspection under the
procedures in § 91.55-15 of this chapter.
(b) The person requesting an endorsement under paragraph (a) of this section must submit to the Coast
Guard, if requested—
(1) Calculations for hull design required by § 172.175 of this chapter;
(2) The plans and information listed in §§ 54.01-18, 56.01-10, 91.55-5 (a), (b), (d), (g), and (h), and
110.25-1 of this chapter;
(3) Plans for the dry chemical supply and distribution systems, including the controls; and
(4) Any other vessel information, including, but not limited to plans, design calculations, test results,
certificates, and manufacturer's data, needed to determine whether or not the vessel meets the
standards of this part.
§ 154.17 U.S. flag vessel: Certificate of Inspection endorsement.
The Certificate of Inspection for a U.S. flag vessel allowed to carry a liquefied gas listed in Table 4 has the following
endorsement for each cargo, with the corresponding carriage requirement data inserted:
46 CFR 154.17 (enhanced display)
page 17 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.19
Inspected and approved for the carriage of ______ at a maximum allowable relief valve setting of ______ kPa
gauge (______ psig) with an F factor of ______, a maximum external pressure of ______ kPa gauge (______ psig), a
minimum service temperature of ______ °C (______ °F), and a maximum specific gravity of ______. Hull type
______.
§ 154.19 U.S. flag vessel: IMO certificate issuance.
(a) Either a classification society authorized under 46 CFR part 8, or the Coast Guard Officer in Charge, Marine
Inspection, issues an IMO Certificate to a U.S. flag vessel when requested by the owner or representative,
if—
(1) The vessel meets the requirements of this part; and
(2) It is a new gas vessel, it meets the IMO Resolution A.328(IX), “Code for the Construction and
Equipment of Ships Carrying Liquefied Gases in Bulk, 1975”; or
(3) It is an existing gas vessel, it meets the IMO “Code for Existing Ships Carrying Liquefied Gases in
Bulk, 1975”.
(b) The IMO Certificate expires on the same date that the vessel's Certificate of Inspection expires.
[CGD 77-069, 52 FR 31626, Aug. 21, 1987, as amended by CGD 95-010, 62 FR 67537, Dec. 24, 1997]
§ 154.22 Foreign flag vessel: Certificate of Compliance endorsement application.
(a) A person who desires an endorsed Certificate of Compliance to meet § 154.1802(a) of this part for a
foreign flag vessel, whose flag administration issues IMO Certificates, must submit to the 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, an application that includes the
following:
(1) The vessel's valid IMO Certificate.
(2) A description of the vessel.
(3) Specifications for the cargo containment system.
(4) A general arrangement plan of the vessel.
(5) A midship section plan of the vessel.
(6) Schematic plans of the liquid and vapor cargo piping.
(7) A firefighting and safety plan.
(8) If the applicant is requesting an endorsement for the carriage of ethylene oxide, a classification
society certification that the vessel meets § 154.1725(a) (4), (5), and (7).
(9) If the vessel is a new gas vessel, or an existing vessel that does not meet § 154.12 (b), (c), or (d)—
(i)
A certification from a classification society that the vessel—
(A) Has enhanced grades of steel meeting § 154.170 (b)(1) and (b)(2) for crack arresting
purposes in the deck stringer, sheer strake, and bilge strake; and
46 CFR 154.22(a)(9)(i)(A) (enhanced display)
page 18 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.22(a)(9)(i)(B)
(B) Meets § 154.701, or if the vessel carries methane, meets § 154.703, by having the
capability of cargo tank pressure and temperature control without venting; and
(ii) The vessel's valid SOLAS Cargo Ship Safety Construction Certificate and Cargo Ship Safety
Equipment Certificate.
(10) Any additional plans, certificates, and information needed by the Commanding Officer, Marine Safety
Center to determine whether or not the vessel meets this part.
(b) A person who desires an endorsed Certificate of Compliance to meet § 154.1802(b) for a foreign flag
vessel, whose flag administration does not issue IMO Certificates, must submit to the Commanding
Officer, Marine Safety Center the plans, calculations, and information under § 154.15(b).
[CGD 77-069, 52 FR 31626, Aug. 21, 1987, as amended by CGD 88-070, 53 FR 34535, Sept. 7, 1988; CGD 89-025, 54 FR 19571,
May 8, 1989; CGD 95-072, 60 FR 50466, Sept. 29, 1995; 60 FR 54106, Oct. 19, 1995; USCG-2005-23172, 70 FR 75734, Dec. 21,
2005; USCG-2007-29018, 72 FR 53967, Sept. 21, 2007; USCG-2013-0671, 78 FR 60155, Sept. 30, 2013; USCG-2016-0498, 82 FR
35092, July 28, 2017]
§ 154.24 Foreign flag vessel: IMO Certificate.
(a) An IMO Certificate issued under the IMO Resolution A.328(IX),”Code for the Construction and Equipment
of Ships Carrying Liquefied Gases in Bulk, 1975” is usually sufficient evidence of compliance with this part
for the Coast Guard to endorse a foreign flag vessel's Certificate of Compliance with the name of each
cargo in Table 4 (follows § 154.1872) that is listed on the IMO Certificate, if the information listed in item
3 of the IMO Certificate shows that—
(1) The design ambient temperatures meet § 154.174 and § 154.176;
(2) The cargo tank design stress factors and resulting MARVS of independent tanks type B or C meet §
154.447 or § 154.450; and
(3) The cargo tank MARVS of a type IIPG ship meets § 172.175(c) of this chapter.
(b) If a foreign flag existing gas vessel meets § 154.12 (b), (c), or (d), the vessel's IMO Certificate issued
under the IMO “Code for Existing Ships Carrying Liquefied Gases in Bulk, 1975” is usually sufficient
evidence of compliance with the requirements of § 154.12(e) for the Coast Guard to endorse the
Certificate of Compliance with the name of each cargo in Table 4 (follows § 154.1872) that is listed on the
IMO Certificate; however if a foreign flag existing gas vessel does not meet § 154.12 (b), (c), or (d), an
IMO Certificate issued under the IMO “Code for Existing Ships Carrying Liquefied Gases in Bulk, 1975” is
not acceptable evidence of compliance with the requirements of this part for the endorsement of a
Certificate of Compliance.
§ 154.30 [Reserved]
§ 154.32 Equivalents.
(a) A vessel that fails to meet the standards in this part for an endorsement on a Certificate of Inspection or a
Certificate of Compliance may meet an alternate standard if the Commandant (CG-ENG) finds that the
alternate standard provides an equivalent or greater level of protection for the purpose of safety.
(b) The Commandant (CG-ENG) considers issuance of a finding of equivalence to the standard required by
this part if the person requesting the finding submits a written application to the Commandant (CG-ENG)
that includes—
46 CFR 154.32(b) (enhanced display)
page 19 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.32(b)(1)
(1) A detailed explanation of the vessel's characteristics that do not meet the requirements in this part;
and
(2) An explanation of how each substituted standard would enable the vessel to meet a level of safety
that would be equivalent to or greater than the standard in this part.
(c) Operational methods or procedures may not be substituted for a particular fitting, material, appliance,
apparatus, item, or type of equipment required in this part.
§ 154.34 Special approval: Requests.
Each request for special approval must be in writing and submitted to the Commandant (CG-ENG), Attn: Office of
Design and Engineering Systems, U.S. Coast Guard Stop 7509, 2703 Martin Luther King Jr. Avenue SE., Washington,
DC 20593-7509.
[CGD 77-069, 52 FR 31626, Aug. 21, 1987, as amended by USCG-2013-0671, 78 FR 60155, Sept. 30, 2013]
§ 154.36 Correspondence and vessel information: Submission.
Correspondence to the Coast Guard and all vessel information submitted to the Coast Guard must be in English,
except—
(a) IMO Certificates may be in French; and
(b) SOLAS Certificates may be in the official language of the flag administration.
§ 154.40 Right of appeal.
Any person directly affected by a decision or action taken under this part, 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 50381, Dec. 6, 1989]
Subpart B—Inspections and Tests
EXAMINATION REQUIREMENTS FOR FOREIGN FLAG VESSELS
§ 154.150 Examination required for a Certificate of Compliance.
Before a vessel receives an initial or reissued Certificate of Compliance endorsed with the name of a cargo from
Table 4 of this part, the vessel must call at a United States port for an examination, during which the Officer in
Charge, Marine Inspection, determines whether or not the vessel meets the requirements of this chapter.
[CGD 81-052, 50 FR 8734, Mar. 5, 1985]
§ 154.151 Procedures for having the Coast Guard examine a vessel for a Certificate of
Compliance.
To have the Coast Guard examine the vessel for a Certificate of Compliance, as required in § 154.150, the owner of
a foreign flag vessel must proceed as follows:
46 CFR 154.151 (enhanced display)
page 20 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.151(a)
(a) After submitting an application under § 154.22, await notification by the Commanding Officer, Marine
Safety Center that review of the vessel's plans or IMO Certificate and supporting documents is complete.
(b) Except when paragraph (c) of this section applies,
(1) After receiving notification from Commanding Officer, Marine Safety Center that review is complete
and the application is acceptable, dispatch the vessel to a United States port;
(2) Notify the Officer in Charge, Marine Inspection, for the port where the vessel is to be inspected at
least seven days before the vessel arrives and arrange the exact time and other details of the
examination. This notification is in addition to any other pre-arrival notice to the Coast Guard
required by other regulations and must include:
(i)
The name of the vessel's first U.S. port of call;
(ii) The date the vessel is scheduled to arrive;
(iii) The name and telephone number of the owner's local agent; and
(iv) The names of all cargoes listed in Table 4 of this part that are on board the vessel;
(3) Make sure that the following items are available on board the vessel for the use of the Marine
Inspector before beginning the examination required by § 154.150:
(i)
A general arrangement (including the location of firefighting, safety, and lifesaving gear); and
(ii) The cargo manual required by § 154.1810.
(c) If the vessel was accepted for U.S. service on the basis of Coast Guard plan review under § 154.22(b), the
vessel owner must notify Commanding Officer, Marine Safety Center 14 days prior to the vessel's arrival at
a U.S. port. This notification must include:
(1) The name of the vessel's first U.S. port of call;
(2) The date the vessel is scheduled to arrive;
(3) The name and telephone number of the owner's local agent; and
(4) The names of all cargoes listed in Table 4 of this part that are on board the vessel.
[CGD 81-052, 50 FR 8734, Mar. 5, 1985; 50 FR 15895, Apr. 23, 1985; CGD 77-069, 52 FR 31630, Aug. 21, 1987; CGD 95-072, 60 FR
50466, Sept. 29, 1995; 60 FR 54106, Oct. 19, 1995; USCG-2013-0671, 78 FR 60155, Sept. 30, 2013]
Subpart C—Design, Construction and Equipment
HULL STRUCTURE
§ 154.170 Outer hull steel plating.
(a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck
plating must meet the material standards of the American Bureau of Shipping published in “Rules for
Building and Classing Steel Vessels” 1981.
(b) Along the length of the cargo area, grades of steel must be as follows:
46 CFR 154.170(b) (enhanced display)
page 21 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.170(b)(1)
(1) The deck stringer and sheer strake must be at least Grade E steel or a grade of steel that has
equivalent chemical properties, mechanical properties, and heat treatment, and that is specially
approved by the Commandant (CG-ENG).
(2) The strake at the turn of the bilge must be Grade D, Grade E, or a grade of steel that has equivalent
chemical properties, mechanical properties, and heat treatment, and that is specially approved by
the Commandant (CG-ENG).
(3) The outer hull steel of vessels must meet the standards in § 154.172 if the hull steel temperature is
calculated to be below −5 °C (23 °F) assuming:
(i)
For any waters in the world, the ambient cold conditions of still air at 5 °C (41 °F) and still sea
water at 0 °C (32 °F);
(ii) For cargo containment systems with secondary barriers, the temperature of the secondary
barrier is the design temperature; and
(iii) For cargo containment systems without secondary barriers, the temperature of the cargo tank
is the design temperature.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983; CGD 77-069, 52 FR 31630, Aug.
21, 1987]
§ 154.172 Contiguous steel hull structure.
(a) Except as allowed in paragraphs (b) and (c) of this section, plates, forgings, forged and rolled fittings, and
rolled and forged bars and shapes used in the construction of the contiguous steel hull structure must
meet the thickness and steel grade in Table 1 for the temperatures under §§ 154.174(b) and 154.176(b).
(b) for a minimum temperature, determined under §§ 154,174(b) and 154.176(b), below −25 °C (−13 °F), the
contiguous steel hull structure must meet § 54.25-10 for that minimum temperature.
(c) If a steel grade that is not listed in Table 1 has the equivalent chemical properties, mechanical properties,
and heat treatment of a steel grade that is listed, the steel grade not listed may be specially approved by
the Commandant (CG-ENG), for use in the contiguous hull structure.
Table 1—Minimum Temperature, Thickness, and Steel Grades in Contiguous
Hull Structures
Minimum
temperature
Steel
thickness
Steel1 grade
0 °C (32 °F)
All
Standards of the American Bureau of Shipping published in “Rules for
Building and Classing Steel Vessels”, 1981
−10 °C (14
°F)
T≤112.5 mm
(1⁄2 in.)
B
12.525.5 mm (1
in.)
E
t≤112.5 mm
D
−25 °C (−13
46 CFR 154.172(c) (enhanced display)
page 22 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
Minimum
temperature
°F)
Steel
thickness
46 CFR 154.174
Steel1 grade
(1⁄2 in.)
>12.5 mm (1⁄2
in.)
E
1
Steel grade of the American Bureau of Shipping published in “Rules for Building and Classing
Steel Vessels”, 1981.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983; CGD 77-069, 52 FR 31630, Aug.
21, 1987]
§ 154.174 Transverse contiguous hull structure.
(a) The transverse contiguous hull structure of a vessel having cargo containment systems without
secondary barriers must meet the standards of the American Bureau of Shipping published in “Rules for
Building and Classing Steel Vessels”, 1981.
(b) The transverse contiguous hull structure of a vessel having cargo containment systems with secondary
barriers must be designed for a temperature that is:
(1) Colder than the calculated temperature of this hull structure when:
(i)
The temperature of the secondary barrier is the design temperature, and
(ii) The ambient cold condition under § 154.176(b)(1)(ii) and (iii) are assumed; or
(2) Maintained by the heating system under § 154.178.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]
§ 154.176 Longitudinal contiguous hull structure.
(a) The longitudinal contiguous hull structure of a vessel having cargo containment systems without
secondary barriers must meet the standards of the American Bureau of Shipping published in “Rules for
Building and Classing Steel Vessels”, 1981.
(b) The longitudinal contiguous hull structure of a vessel having cargo containment systems with secondary
barriers must be designed for a temperature that is:
(1) Colder than the calculated temperature of this hull structure when:
(i)
The temperature of the secondary barrier is the design temperature; and
(ii) For any waters in the world except Alaskan waters, the ambient cold condition of:
(A) Five knots air at −18 °C (0 °F); and
(B) Still sea water at 0 °C (32 °F); or
(iii) For Alaskan waters the ambient cold condition of:
(A) Five knots air at −29 °C (−20 °F); and
46 CFR 154.176(b)(1)(iii)(A) (enhanced display)
page 23 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.176(b)(1)(iii)(B)
(B) Still sea water at −2 °C (28 °F); or
(2) Maintained by the heating system under § 154.178, if, without heat, the contiguous hull structure is
designed for a temperature that is colder than the calculated temperature of the hull structure
assuming the:
(i)
Temperature of the secondary barrier is the design temperature; and
(ii) Ambient cold conditions of still air at 5 °C (41 °F) and still sea water at 0 °C (32 °F).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]
§ 154.178 Contiguous hull structure: Heating system.
The heating system for transverse and longitudinal contiguous hull structure must:
(a) Be shown by a heat load calculation to have the heating capacity to meet § 154.174(b)(2) or §
154.176(b)(2);
(b) Have stand-by heating to provide 100% of the required heat load and distribution determined under
paragraph (a); and
(c) Meet Parts 52, 53, and 54 of this chapter.
§ 154.180 Contiguous hull structure: Welding procedure.
Welding procedure tests for contiguous hull structure designed for a temperature colder than −18 °C (0 °F) must
meet § 54.05-15 and subpart 57.03 of this chapter.
§ 154.182 Contiguous hull structure: Production weld test.
If a portion of the contiguous hull structure is designed for a temperature colder than −34 °C (−30 °F) and is not part
of the secondary barrier, each 100m (328 ft.) of full penetration butt welded joints in that portion of the contiguous
hull structure must pass the following production weld tests in the position that the joint is welded:
(a) Bend tests under § 57.06-4 of this chapter.
(b) A Charpy V-notch toughness test under § 57.06-5 of this chapter on one set of 3 specimens alternating
the notch location on successive tests between the center of the weld and the most critical location in the
heat affected zone.[2]
(c) If the contiguous hull structure does not pass the test under paragraph (b) of this section, the retest
procedures under § 54.05-5(c) must be met.
§ 154.188 Membrane tank: Inner hull steel.
For a vessel with membrane tanks, the inner hull plating thickness must meet the deep tank requirements of the
American Bureau of Shipping published in “Rules for Building and Classing Steel Vessels”, 1981.
[2]
The most critical location in the heat affected zone of the weld is based on procedure qualification results,
except austenitic stainless steel need have notches only in the center of the weld.
46 CFR 154.188 (enhanced display)
page 24 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.195
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]
§ 154.195 Aluminum cargo tank: Steel enclosure.
(a) An aluminum cargo tank and its dome must be enclosed by the vessel's hull structure or a separate steel
cover.
(b) The steel cover for the aluminum cargo tank must meet the steel structural standards of the American
Bureau of Shipping published in “Rules for Building and Classing Steel Vessels”, 1981.
(c) The steel cover for the aluminum tank dome must be:
(1) At least 3.2 mm (1⁄8 in.) thick;
(2) Separated from the tank dome, except at the support points; and
(3) Thermally isolated from the dome.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]
SHIP SURVIVAL CAPABILITY AND CARGO TANK LOCATION
§ 154.200 Stability requirements: General.
Each vessel must meet the applicable requirements in subchapter S of this chapter.
[CGD 79-023, 48 FR 51009, Nov. 4, 1983]
§ 154.235 Cargo tank location.
(a) For type IG hulls, cargo tanks must be located inboard of:
(1) The transverse extent of damage for collision penetration specified in Table 172.180 of this chapter;
(2) The vertical extent of damage for grounding penetration specified in Table 172.180 of this chapter;
and
(3) 30 inches (760 mm) from the shell plating.
(b) For type IIG, IIPG, and IIIG hulls, cargo tanks must be located inboard of:
(1) The vertical extent of damage for grounding penetration specified in Table 172.180 of this chapter;
and
(2) 30 inches (760 mm) from the shell plating.
(c) In vessels having membrane and semi-membrane tanks, the vertical and transverse extents of damage
must be measured to the inner hull.
(d) For type IIG, IIPG, and IIIG hulls, cargo tank suction wells may penetrate into the area of bottom damage
specified as the vertical extent of damage for grounding penetration in Table 172.180 of this chapter if the
penetration is the lesser of 25% of the double bottom height or 13.8 in. (350 mm).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 79-023, 48 FR 51010, Nov. 4, 1983]
46 CFR 154.235(d) (enhanced display)
page 25 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.300
SHIP ARRANGEMENTS
§ 154.300 Segregation of hold spaces from other spaces.
Hold spaces must be segregated from machinery and boiler spaces, accommodation, service and control spaces,
chain lockers, potable, domestic and feed water tanks, store rooms and spaces immediately below or outboard of
hold spaces by a:
(a) Cofferdam, fuel oil tank, or single gastight A-60 Class Division of all welded construction in a cargo
containment system not required by this part to have a secondary barrier;
(b) Cofferdam or fuel oil tank in a cargo containment system required by this part to have a secondary barrier;
or
(c) If there are no sources of ignition or fire hazards in the adjoining space, single gastight A-O Class Division
of all welded construction.
§ 154.305 Segregation of hold spaces from the sea.
In vessels having cargo containment systems required by this part to have a secondary barrier, hold spaces must be
segregated from the sea by:
(a) A double bottom if the cargo tanks meet this part for design temperatures colder than −10 °C (14 °F); and
(b) Wing tanks if the cargo tanks meet this part for design temperatures colder than −55 °C (−67 °F).
§ 154.310 Cargo piping systems.
Cargo liquid or vapor piping must:
(a) Be separated from other piping systems, except where an interconnection to inert gas or purge piping is
required by § 154.901(a);
(b) Not enter or pass through any accommodation, service, or control space;
(c) Except as allowed under § 154.703, not enter or pass through a machinery space other than a cargo pump
or compressor room;
(d) Be in the cargo area except:
(1) As allowed under § 154.703;
(2) Bow and stern loading piping; and
(3) Emergency jettisoning piping.
(e) Be above the weather deck except:
(1) As allowed under § 154.703;
(2) Pipes in a trunk traversing void spaces above a cargo containment system; and
(3) Pipes for draining, venting, or purging interbarrier and hold spaces;
(f) Connect into the cargo containment system above the weather deck except:
46 CFR 154.310(f) (enhanced display)
page 26 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.310(f)(1)
(1) Pipes in a trunk traversing void spaces above a cargo containment system; and
(2) Pipes for draining, venting, or purging interbarrier and hold spaces.
(g) Be inboard of the transverse cargo tank location required by § 154.235, except for athwartship shore
connection manifolds not subject to internal pressure at sea.
§ 154.315 Cargo pump and cargo compressor rooms.
(a) Cargo pump rooms and cargo compressor rooms must be above the weather deck and must be within the
cargo area.
(b) Where pumps and compressors are driven by a prime mover in an adjacent gas safe space:
(1) The bulkhead or deck must be gastight; and
(2) The shafting passing through the bulkhead or deck must be sealed by a fixed oil reservoir gland seal,
a pressure grease seal, or another type of positive pressure seal specially approved by the
Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.320 Cargo control stations.
(a) Cargo control stations must be above the weather deck.
(b) If a cargo control station is in accommodation, service, or control spaces or has access to such a space,
the station must:
(1) Be a gas safe space;
(2) Have an access to the space that meets § 154.330; and
(3) Have indirect reading instrumentation, except for gas detectors.
(c) Cargo control stations, including a room or area, must contain all alarms, indicators, and remote controls
associated with each cargo tank that the station controls.
§ 154.325 Accommodation, service, and control spaces.
(a) Accommodation, service, and control spaces must be outside the cargo area.
(b) If a hold space having a cargo containment system, required by this part to have a secondary barrier, is
separated from any accommodation, service, or control space by a cruciform joint, there must be a
cofferdam providing at least 760 mm (30 inches) by 760 mm (30 inches) clearance on one side of the
cruciform joint.
§ 154.330 Openings to accommodation, service, or control spaces.
(a) Entrances, forced or natural ventilation intakes and exhausts, and other openings to accommodation,
service, or control spaces, except as allowed in paragraph (c) of this section, must be:
(1) At least L/25 or 3.05m (10 ft) from the athwartship bulkhead facing the cargo area, whichever is
farther, except that the distance need not exceed 5m (16.4 ft); and
(2) On a house athwartship bulkhead not facing the cargo area or on the outboard side of the house.
46 CFR 154.330(a)(2) (enhanced display)
page 27 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.330(b)
(b) Each port light, located on the athwartship bulkhead of a house facing the cargo area or the house sides
within the distance specified in paragraph (a)(1) of this section, must be a fixed type.
(c) Wheelhouse doors and windows that are not fixed may be within the distance specified in paragraph
(a)(1) of this section from the athwartship bulkhead of a house facing the cargo area, if they have gaskets
and pass a tightness test with a fire hose at not less than 207 kPa gauge (30 psig).
(d) Port lights in the hull plating below the uppermost continuous deck and in the first tier of the
superstructure must be a fixed type.
(e) Air intakes and openings into accommodation, service, and control spaces must have metal closures that
pass a tightness test with a fire hose at not less than 207 kPa gauge (30 psig).
(f) On liquefied toxic gas vessels, the closures required in paragraph (e) of this section must be capable of
being closed from inside the space.
§ 154.340 Access to tanks and spaces in the cargo area.
(a) Each cargo tank must have a manhole from the weather deck, the clear opening of which is at least 600
mm by 600 mm (23.6 in. by 23.6 in.).
(b) Each access into and through a void space or other gas-dangerous space in the cargo area, except spaces
described in paragraph (e) of the definition for “gas-dangerous space” in § 154.7, must—
(1) Have a clear opening of at least 600 mm by 600 mm (23.6 in. by 23.6 in.) through horizontal
openings, hatches, or manholes;
(2) Have a clear opening of at least 600 mm by 800 mm (23.6 in. by 31.5 in.) through bulkheads, frames
or other vertical structural members; and
(3) Have a fixed ladder if the lower edge of a vertical opening is more than 600 mm (23.6 in.) above the
deck or bottom plating.
(c) Each access trunk in the cargo area must be at least 760 mm (30 in.) in diameter.
(d) The lower edge of each access from the weather deck to gas-safe spaces in the cargo area must be at
least 2.4 m (7.9 ft.) above the weather deck or the access must be through an air lock that meets §
154.345.
(e) The inner hull in the cargo area must be accessible for inspection from at least one side without the
removal of any fixed structure or fitting.
(f) The hold space insulation in the cargo area must be accessible for inspection from at least one side from
within the hold space or there must be a means, that is specially approved by the Commandant, of
determining from outside the hold space whether or not the hold space insulation meets this part.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]
§ 154.345 Air locks.
(a) An air lock may be used for access from a gas-dangerous zone on the weather deck to a gas-safe space.
(b) Each air lock must:
46 CFR 154.345(b) (enhanced display)
page 28 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.345(b)(1)
(1) Consist of two steel doors, at least 1.5 m (4.9 ft.) but not more than 2.5 m (8.2 ft.) apart, each
gasketed and tight when tested with a fire hose at not less 207 kPa gauge (30 psig);
(2) Have self-closing doors with no latches or other devices for holding them open;
(3) Have an audible and visual alarm on both sides which are actuated when both door securing devices
are in other than the fully closed position at the same time;
(4) Have mechanical ventilation in the space between the doors from a gas-safe area;
(5) Have a pressure greater than that of the gas-dangerous area on the weather deck;
(6) Have the rate of air change in the space between the doors of at least 8 changes per hour; and
(7) Have the space between the doors monitored for cargo vapor leaks under § 154.1350.
(c) In addition to the requirements of paragraphs (a) and (b) of this section, no gas-safe space on a liquefied
flammable gas carrier may have an air lock unless the space:
(1) Is mechanically ventilated to make the pressure in the space greater than that in the air lock; and
(2) Has a means of automatically de-energizing all electrical equipment that is not explosion-proof in the
space when the pressure in the space falls to or below the pressure in the air lock.
§ 154.350 Bilge and ballast systems in the cargo area.
(a) Hold, interbarrier, and insulation spaces must have a means of sounding the space or other means of
detecting liquid leakage specially approved by the Commandant (CG-ENG).
(b) Each hold and insulation space must have a bilge drainage system.
(c) Interbarrier spaces must have an eductor or pump for removing liquid cargo and returning it to the cargo
tanks or to an emergency jettisoning system meeting § 154.356.
(d) Spaces in the cargo containment portion of the vessel, except ballast spaces and gas-safe spaces, must
not connect to pumps in the main machinery space.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.355 Bow and stern loading piping.
(a) Bow and stern loading piping must:
(1) Meet § 154.310;
(2) Be installed in an area away from the accommodation, service, or control space on type IG hulls;
(3) Be clearly marked;
(4) Be segregated from the cargo piping by a removable spool piece in the cargo area or by at least two
shut-off valves in the cargo area that have means of locking to meet § 154.1870(a);
(5) Have a means for checking for cargo vapor between the two valves under paragraph (a)(4) of this
section;
(6) Have fixed inert gas purging lines; and
(7) Have fixed vent lines for purging with inert gas to meet § 154.1870(b).
46 CFR 154.355(a)(7) (enhanced display)
page 29 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.355(b)
(b) Entrances, forced or natural ventilation intakes, exhausts, and other openings to accommodation, service,
or control spaces that face the bow or stern loading area must meet § 154.330.
§ 154.356 Cargo emergency jettisoning piping.
Emergency jettisoning piping must:
(a) Meet § 154.355(a);
(b) Be designed to allow cargo discharge without the outer hull steel temperature falling below the minimum
temperatures under §§ 154.170 and 154.172; and
(c) Be specially approved by the Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
CARGO CONTAINMENT SYSTEMS
§ 154.401 Definitions.
As used in §§ 154.440 and 154.447:
“σY” means the minimum yield strength of the tank material, including weld metal, at room temperature.
“σB” means minimum tensile strength of the tank material, including weld metals, at room temperature.
§ 154.405 Design vapor pressure (Po) of a cargo tank.
(a) The design vapor pressure (Po) of a cargo tank must be equal to or greater than the MARVS.
(b) The Po of a cargo tank must be equal to or greater than the vapor pressure of the cargo at 45 °C (113 °F)
if:
(1) The cargo tank has no temperature control for the cargo; and
(2) The vapor pressure of the cargo results solely from ambient temperature.
(c) The Po of a cargo tank may be exceeded under harbor conditions if specially approved by the
Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.406 Design loads for cargo tanks and fixtures: General.
(a) Calculations must show that a cargo tank and its fixtures are designed for the following loads:
(1) Internal pressure head.
(2) External pressure load.
(3) Dynamic loads resulting from the motion of the vessel.
(4) Transient or stationary thermal loads if the design temperature is colder than −55 °C (−67 °F) or
causes thermal stresses in cargo tank supports.
46 CFR 154.406(a)(4) (enhanced display)
page 30 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.406(a)(5)
(5) Sloshing loads, if the cargo tank is designed for partial loads.
(6) Loads resulting from vessel's deflection.
(7) Tank weight, cargo weight, and corresponding support reaction.
(8) Insulation weight.
(9) Loads of a pipe tower and any other attachments to the cargo tank.
(10) Vapor pressure loads in harbor conditions allowed under § 154.405.
(11) Gas pressurization if the cargo tank is designed for gas pressurization as a means of cargo transfer.
(b) A cargo tank must be designed for the most unfavorable static heel angle within a 0° to 30° range without
exceeding the allowable stress of the material.
(c) A hydrostatic or hydropneumatic test design load must be specially approved by the Commandant (CGENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983; USCG-2014-0688, 79 FR 58284,
Sept. 29, 2014]
§ 154.407 Cargo tank internal pressure head.
(a) For the calculation required under § 154.406(a)(1) and (b), the internal pressure head (heq), must be
determined from the following formula:
heq = 10 Po + (hgd)max
where:
hgd (the value of internal pressure, in meters of fresh water, resulting from the combined effects of gravity and
dynamic accelerations of a full tank) = aβ Zβ Y;
where:
aβ = dimensionless acceleration relative to the acceleration of gravity resulting from gravitational and dynamic
loads in the β direction (see figure 1);
Zβ = largest liquid height (m) above the point where the pressure is to be determined in the β direction (see
figure 2);
Y = maximum specific weight of the cargo (t/m3) at the design temperature.
46 CFR 154.407(a) (enhanced display)
page 31 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.407(a) (enhanced display)
46 CFR 154.407(a)
page 32 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.407(b)
(b) The (hgd)max is determined for the β direction, on the ellipse in Figure 1, which gives the maximum value
for hgd.
(c) When the longitudinal acceleration is considered in addition to the vertical transverse acceleration, an
ellipsoid must be used in the calculations instead of the ellipse contained in Figure 1.
46 CFR 154.407(c) (enhanced display)
page 33 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.408
§ 154.408 Cargo tank external pressure load.
For the calculation required under § 154.406 (a)(2) and (b), the external pressure load must be the difference
between the minimum internal pressure (maximum vacuum), and the maximum external pressure to which any
portion of the cargo tank may be simultaneously subjected.
§ 154.409 Dynamic loads from vessel motion.
(a) For the calculation required under § 154.406 (a)(3) and (b), the dynamic loads must be determined from
the long term distribution of vessel motions, including the effects of surge, sway, heave, roll, pitch, and
yaw on irregular seas that the vessel may experience during 108 wave encounters. The speed used for
this calculation may be reduced from the ship service speed if specially approved by the Commandant
(CG-ENG) and if that reduced speed is used in the hull strength calculation under § 31.10-5(c) of this
chapter.
(b) If the loads determined under paragraphs (c), (d), or (e) of this section result in a design stress that is
lower than the allowable stress of the material under §§ 154.610, 154.615, or 154.620, the allowable
stress must be reduced to that stress determined in paragraphs (c), (d), or (e).
(c) If a tank is designed to avoid plastic deformation and buckling, then acceleration components of the
dynamic loads must be determined for the largest loads the vessel may experience during an operating
life corresponding to the probability level of 10−8, by using one of the following methods:
(1) Method 1 is a detailed analysis of the vessel's acceleration components.
(2) Method 2 applies to vessels of 50 m (164 ft) or more in length and is an analysis by the following
formulae that corresponds to a 10−8 probability level in the North Atlantic:
(i)
Vertical acceleration under paragraph (f)(1) of this section:
46 CFR 154.409(c)(2)(i) (enhanced display)
page 34 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.409(c)(2)(i) (enhanced display)
46 CFR 154.409(c)(2)(i)
page 35 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.409(c)(2)(i) (enhanced display)
46 CFR 154.409(c)(2)(i)
page 36 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.409(d)
(d) If a cargo tank is designed to avoid fatigue, the dynamic loads determined under paragraph (a) of this
section must be used to develop the dynamic spectrum.
(e) If a cargo tank is designed to avoid uncontrolled crack propagation, the dynamic loads are:
(1) Determined under paragraph (a) of this section; and
(2) For a load distribution for a period of 15 days by the method in Figure 3.
46 CFR 154.409(e)(2) (enhanced display)
page 37 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.409(e)(2) (enhanced display)
46 CFR 154.409(e)(2)
page 38 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.409(f)
(f) When determining the accelerations for dynamic loads under paragraph (a) of this section, the
accelerations acting in a cargo tank must be estimated for the cargo tank's center of gravity and include
the following component accelerations:
(1) Vertical accelerations, meaning the motion acceleration of heave and pitch, and of any roll normal to
the vessel base that has an effect on the component acceleration.
(2) Transverse acceleration, meaning the motion acceleration of sway, yaw and roll, and gravity
component of roll.
(3) Longitudinal acceleration, meaning the motion acceleration of surge and pitch and gravity
component of pitch.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.410 Cargo tank sloshing loads.
(a) For the calculation required under § 154.406 (a)(5) and (b), the determined sloshing loads resulting from
the accelerations under § 154.409(f) must be specially approved by the Commandant (CG-ENG).
(b) If the sloshing loads affect the cargo tank scantlings, an analysis of the effects of the sloshing loads in
addition to the calculation under paragraph (a) of this section must be specially approved by the
Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.411 Cargo tank thermal loads.
For the calculations required under § 154.406(a)(4), the following determined loads must be specially approved by
the Commandant (CG-ENG):
(a) Transient thermal loads for the cooling down periods of cargo tanks for design temperatures lower than
−55 °C (−67 °F).
(b) Stationary thermal loads for cargo tanks for design temperatures lower than −55 °C (−67 °F) that cause
high thermal stress.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.412 Cargo tank corrosion allowance.
A cargo tank must be designed with a corrosion allowance if the cargo tank:
(a) is located in a space that does not have inert gas or dry air; or
(b) carries a cargo that corrodes the tank material.
Note: Corrosion allowance for independent tank type C is contained in § 54.01-35 of this chapter.
INTEGRAL TANKS
46 CFR 154.412(b) (enhanced display)
page 39 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.418
§ 154.418 General.
An integral tank must not be designed for a temperature colder than −10 °C (14 °F), unless the tank is specially
approved by the Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.419 Design vapor pressure.
The Po of an integral tank must not exceed 24.5 kPa gauge (3.55 psig) unless special approval by the Commandant
(CG-ENG) allows a Po between 24.5 kPa gauge (3.55 psig) and 69 kPa gauge (10 psig).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.420 Tank design.
(a) The structure of an integral tank must meet the deep tank scantling standards of the American Bureau of
Shipping published in “Rules for Building and Classing Steel Vessels”, 1981.
(b) The structure of an integral tank must be designed and shown by calculation to withstand the internal
pressure determined under § 154.407.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]
§ 154.421 Allowable stress.
The allowable stress for the integral tank structure must meet the American Bureau of Shipping's allowable stress
for the vessel's hull published in “Rules for Building and Classing Steel Vessels”, 1981.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]
MEMBRANE TANKS
§ 154.425 General.
The design of the hull structure and the design of the membrane tank system, that includes the membrane tank,
secondary barrier, including welds, the supporting insulation, and pressure control equipment, must be specially
approved by the Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.426 Design vapor pressure.
The Po of a membrane tank must not exceed 24.5 kPa gauge (3.55 psig) unless special approval by the
Commandant (CG-ENG) allows a Po between 24.5 kPa gauge (3.55 psig) and 69 kPa gauge (10 psig).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
46 CFR 154.426 (enhanced display)
page 40 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.427
§ 154.427 Membrane tank system design.
A membrane tank system must be designed for:
(a) Any static and dynamic loads with respect to plastic deformation and fatigue;
(b) Combined strains from static, dynamic, and thermal loads;
(c) Preventing collapse of the membrane from:
(1) Over-pressure in the interbarrier space;
(2) Vacuum in the cargo tank;
(3) Sloshing in a partially filled cargo tank; and
(4) Hull vibrations; and
(d) The deflections of the vessel's hull.
§ 154.428 Allowable stress.
The membrane tank and the supporting insulation must have allowable stresses that are specially approved by the
Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.429 Calculations.
The tank design load calculations for a membrane tank must include the following:
(a) Plastic deformation and fatigue life resulting from static and dynamic loads in the membrane and the
supporting insulation.
(b) The response of the membrane and its supporting insulation to vessel motion and acceleration under the
worst weather conditions. Calculations from a similar vessel may be submitted to meet this paragraph.
(c) The combined strains from static, dynamic, and thermal loads.
§ 154.430 Material test.
(a) The membrane and the membrane supporting insulation must be made of materials that withstand the
combined strains calculated under § 154.429(c).
(b) Analyzed data of a material test for the membrane and the membrane supporting insulation must be
submitted to the Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.431 Model test.
(a) The primary and secondary barrier of a membrane tank, including the corners and joints, must withstand
the combined strains from static, dynamic, and thermal loads calculated under § 154.429(c).
46 CFR 154.431(a) (enhanced display)
page 41 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.431(b)
(b) Analyzed data of a model test for the primary and secondary barrier of the membrane tank must be
submitted to the Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.432 Expansion and contraction.
The support system of a membrane tank must allow for thermal and physical expansion and contraction of the
tank.
SEMI-MEMBRANE TANKS
§ 154.435 General.
(a) The design of a semi-membrane tank, the supporting insulation for the tank, and the supporting hull
structure for the tank must be specially approved by the Commandant (CG-ENG).
(b) A semi-membrane tank must be designed to meet:
(1) § 154.425 through § 154.432;
(2) § 154.437 through § 154.440; or
(3) § 154.444 through § 154.449.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.436 Design vapor pressure.
The Po of a semi-membrane tank must not exceed 24.5 kPa gauge (3.55 psig) unless special approval by the
Commandant (CG-ENG) allows a Po between 24.5 kPa gauge (3.55 psig) and 69 kPa gauge (10 psig).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
INDEPENDENT TANK TYPE A
§ 154.437 General.
An independent tank type A must meet § 154.438 through § 154.440.
§ 154.438 Design vapor pressure.
(a) If the surface of an independent tank type A are mostly flat surfaces, the Po must not exceed 69 kPa
gauge (10 psig).
(b) If the surfaces of an independent tank type A are formed by bodies of revolution, the design calculation of
the Po must be specially approved by the Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983; USCG-2014-0688, 79 FR 58284,
Sept. 29, 2014]
46 CFR 154.438(b) (enhanced display)
page 42 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.439
§ 154.439 Tank design.
An independent tank type A must meet the deep tank standard of the American Bureau of Shipping published in
“Rules for Building and Classing Steel Vessels”, 1981, and must:
(a) Withstand the internal pressure determined under § 154.407;
(b) Withstand loads from tank supports calculated under §§ 154.470 and 154.471; and
(c) Have a corrosion allowance that meets § 154.412.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]
§ 154.440 Allowable stress.
(a) The allowable stresses for an independent tank type A must:
(1) For tank web frames, stringers, or girders of carbon manganese steel or aluminum alloys, meet
σB/2.66 or σY/1.33, whichever is less; and
(2) For other materials, be specially approved by the Commandant (CG-ENG).
(b) A greater allowable stress than required in paragraph (a)(1) of this section may be specially approved by
the Commandant (CG-ENG) if the equivalent stress (σc) is calculated from the formula in appendix A of
this part.
(c) Tank plating must meet the American Bureau of Shipping's deep tank standards, for an internal pressure
head that meets § 154.439(a), published in “Rules for Building and Classing Steel Vessels”, 1981.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983; CGD 77-069, 52 FR 31630, Aug.
21, 1987]
INDEPENDENT TANK TYPE B
§ 154.444 General.
An independent tank type B must be designed to meet §§ 154.445 through 154.449.
§ 154.445 Design vapor pressure.
If the surfaces of an independent tank type B are mostly flat surfaces, the Po must not exceed 69 kPa gauge (10
psig).
§ 154.446 Tank design.
An independent tank type B must meet the calculations under § 154.448.
§ 154.447 Allowable stress.
(a) An independent tank type B designed from bodies of revolution must have allowable stresses[3]
determined by the following formulae:
46 CFR 154.447(a) (enhanced display)
page 43 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.447(b)
σm≤f
σL≤1.5 f
σb≤1.5 F
σL + σb≤1.5 F
σm + σb≤1.5 F
where:
σm = equivalent primary general membrane stress[4]
σL = equivalent primary local membrane stress4
σb = equivalent primary bending stress4
f = the lesser of (σB/A) or (σY/B)
F = the lesser of (σB/C) or (σY/D)
A, B, C, and D = stress factors in Table 2.
Table 2—Values for Stress Factors
Nickel steel and carbon manganese steel
values
Austenitic steel
values
Aluminum alloy
values
Stress
factors:
A
4.0
4.0
4.0
B
2.0
1.6
1.5
C
3.0
3.0
3.0
D
1.5
1.5
1.5
(b) An independent tank type B designed from plane surfaces must have allowable stresses specially
approved by the Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
[3]
See Appendix B for stress analyses definitions.
[4]
See Appendix A for equivalent stress.
46 CFR 154.447(b) (enhanced display)
page 44 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.448
§ 154.448 Calculations.
The following calculations for an independent tank type B must be specially approved by the Commandant (CGENG):
(a) Plastic deformation, fatigue life, buckling, and crack propagation resulting from static and dynamic loads
on the tank and its support.
(b) A three-dimensional analysis of the stress exerted by the hull on the tank, its support, and its keys.
(c) The response of the tank and its support to the vessel's motion and acceleration in irregular waves or
calculations from a similar vessel.
(d) A tank buckling analysis considering the maximum construction tolerance.
(e) A finite element analysis using the loads determined under § 154.406.
(f) A fracture mechanics analysis using the loads determined under § 154.406.
(g) The cumulative effects of the fatigue load from the following formula:
where:
ni = the number of stress cycles at each stress level during the life of the vessel;
Ni = the number of cycles to failure for corresponding stress levels from the Wohler (S-N) curve;
Nj = the number of cycles to failure from the fatigue load by loading and unloading the tank; and
Cw = 0.5 or less. A Cw of greater than 0.5 but not exceeding 1.0 may be specially approved by the Commandant
(G-MTH).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.449 Model test.
The following analyzed data of a model test of structural elements for independent tank type B must be submitted
to the Commandant (CG-ENG) for special approval:
(a) Stress concentration factors.
(b) Fatigue life.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
INDEPENDENT TANK TYPE C AND PROCESS PRESSURE VESSELS
46 CFR 154.449(b) (enhanced display)
page 45 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.450
§ 154.450 General.
Independent tanks type C and process pressure vessels must be designed to meet the requirements under Part 54
of this chapter, except § 54.01-40(b), and:
(a) The calculation under § 54.01-18 (b)(1) must also include the design loads determined under § 154.406;
(b) The calculated tank plating thickness, including any corrosion allowance, must be the minimum thickness
without a negative plate tolerance; and
(c) The minimum tank plating thickness must not be less than:
(1) 5mm (3⁄16 in.) for carbon-manganese steel and nickel steel;
(2) 3mm (1⁄8 in.) for austenitic steels; or
(3) 7mm (9⁄32 in.) for aluminum alloys.
§ 154.451 Design vapor pressure.
The Po (kPa) of an independent tank type C must be calculated by the following formula:
Po = 196 + AC(ρ) 3⁄2
where:
A = 1.813 (σm/ΔσA)2;
σm = design primary membrane stress;
Δσ
= (allowable dynamic membrane stress for double amplitude at probability level Q = 10−8) 53.9 MPa (7821
psi) for ferritic and martensitic steels and 24.5 MPa (3555 psi) for 5083-0 aluminum;
A
C = a characteristic tank dimension that is the greatest of h, 0.75b, or 0.45 l;
where:
h = the height of the tank or the dimension in the vessel's vertical direction, in meters;
b = the width of the tank or the dimension in the vessel's transverse direction; in meters; and
l = the length of the tank or the dimension in the vessel's longitudinal direction, in meters; and
ρ
= the specific gravity of the cargo.
§ 154.452 External pressure.
The design external pressure, Pe, for an independent tank type C must be calculated by the following formula:
Pe = P 1 + P 2 + P 3 + P 4
46 CFR 154.452 (enhanced display)
page 46 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.453
where:
P1 = the vacuum relief valve setting for tanks with a vacuum relief valve, or 24.5 kPa gauge (3.55 psig) for tanks
without a vacuum relief valve.
P2 = 0, or the pressure relief valve setting for an enclosed space containing any portion of a pressure vessel.
P3 = total compressive load in the tank shell from the weight of the tank, including corrosion allowance, weight
of insulation, weight of dome, weight of pipe tower and piping, the effect of the partially filled tank, the effect of
acceleration and hull deflection, and the local effect of external and internal pressure.
P4 = 0, or the external pressure from the head of water from any portion of the pressure vessel on exposed
decks.
§ 154.453 Failure to meet independent tank type C standards.
If the Commandant (CG-ENG) determines during plan review, that a tank designed as an independent tank type C
fails to meet the standards under § 154.450, § 154.451, and 154.452 and cannot be redesigned to meet those
standards, the tank may be redesigned as an independent tank type A or B.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983; USCG-2014-0688, 79 FR 58284,
Sept. 29, 2014]
SECONDARY BARRIER
§ 154.459 General.
(a) Each cargo tank must have a secondary barrier that meets Table 3 and except as allowed in Table 3, the
hull must not be the secondary barrier.
(b) If the Commandant (CG-ENG) specially approves an integral tank for a design temperature at atmospheric
pressure lower than −10 °C (14 °F), the integral tank must have a complete secondary barrier that meets §
154.460.
(c) If the Commandant (CG-ENG) specially approves a semi-membrane tank under the requirements of an
independent tank type B, the semi-membrane tank may have a partial secondary barrier specially
approved by the Commandant (CG-ENG).
(d) If Table 3 allows the hull to be a secondary barrier, the vessel's hull must:
(1) Meet §§ 154.605 through 154.630; and
(2) Be designed for the stresses resulting from the design temperature.
46 CFR 154.459(d)(2) (enhanced display)
page 47 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.460
Table 3—Secondary Barriers for Tanks
Cargo temperature (T) at atmospheric pressure
Tank type
T≥−10 °C (14 °F)
T<-10 °C (14 °F)≥55 °C (−67
°F)
T<−55 °C (−67 °F)
Integral
No secondary barrier
required
Tank type not usually
allowed1
Tank type not allowed.
Membrane
......do
Complete secondary barrier1
Complete secondary barrier.
Semimembrane
......do
......do
Do.
......do
......do
Independent:
Type A
1
Do.
barrier1
Type B
......do
Partial secondary
Type C
......do
No secondary barrier
required
Partial secondary barrier.
No secondary barrier
required.
The hull may be a secondary barrier.
(14 U.S.C. 632; 46 U.S.C. 369, 375, and 416; 49 U.S.C. 1655(b); 49 CFR 1.46(b))
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.460 Design criteria.
At static angles of heel up through 30°, a secondary barrier must
(a) If a complete secondary barrier is required in § 154.459, hold all of the liquid cargo in the cargo tank for at
least 15 days under the dynamic loads in § 154.409(e);
(b) If a partial secondary barrier is permitted in § 154.459, hold any leakage of liquid cargo corresponding to
the extent of failure under § 154.448(a) after initial detection or primary barrier leak for at least 15 days
under the dynamic loads in § 154.409(e);
(c) If the primary barrier fails, prevent the temperature of the vessel's structure from falling below the
minimum allowable service temperature of the steel; and
(d) Be designed so that a cargo tank failure does not cause a failure in the secondary barrier.
INSULATION
§ 154.465 General.
If the design temperature is below −10 °C (14 °F), the cargo tank insulation must prevent the temperature of the
vessel's hull from cooling below the minimum temperature allowed under § 154.172.
46 CFR 154.465 (enhanced display)
page 48 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.466
§ 154.466 Design criteria.
(a) The insulation for a cargo tank without a secondary barrier must be designed for the cargo tank at the
design temperature, and for a vessel operating in:
(1) Any waters in the world, except Alaskan waters, for the ambient cold condition of:
(i)
Five knots air at −18 °C (0 °F); and
(ii) Still sea water at 0 °C (32 °F); or
(2) Alaskan waters for the ambient cold condition of:
(i)
Five knots air at −29 °C (20 °F); and
(ii) Still sea water at −2 °C (28 °F).
(b) The insulation for a cargo tank with a secondary barrier must be designed for the secondary barrier at the
design temperature, and the ambient cold conditions listed under paragraph (a)(1) or paragraph (a)(2) of
this section.
(c) The insulation material must be designed for any loads transmitted from adjacent hull structure.
(d) Insulation for cargo tank and piping must meet § 38.05-20 of this chapter.
(e) Powder or granulated insulation must:
(1) Not compact from vibrations of the vessel;
(2) Maintain the thermal conductivity listed under § 154.467; and
(3) Not exert a static pressure greater than the external design pressure of the cargo tank under §
154.408.
§ 154.467 Submission of insulation information.
The following insulation information must be submitted for special approval by the Commandant (CG-ENG):
(a) Compatibility with the cargo.
(b) Solubility in the cargo.
(c) Absorption of the cargo.
(d) Shrinkage.
(e) Aging.
(f) Closed cell content.
(g) Density.
(h) Mechanical properties.
(i)
Thermal expansion.
(j)
Abrasion.
(k) Cohesion.
46 CFR 154.467(k) (enhanced display)
page 49 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
(l)
46 CFR 154.467(l)
Thermal conductivity.
(m) Resistance to vibrations.
(n) Resistance to fire and flame spread.
(o) The manufacturing and installation details of the insulation including:
(1) Fabrication;
(2) Storage;
(3) Handling;
(4) Erection; and
(5) Quality control.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
SUPPORT SYSTEM
§ 154.470 General.
(a) A cargo tank must have a support system that:
(1) prevents movement of the cargo tank under the static and dynamic loads in § 154.406; and
(2) allows the cargo tank to contract and expand from temperature variation and hull deflection without
exceeding the design stress of the cargo tank and the hull.
(b) The cargo tank support system must have a key that prevents rotation of the cargo tank.
(c) An independent tank must have supports with an antifloatation system that withstands the upward force
of the tank without causing plastic deformation that endangers the hull structure when the tank is:
(1) Empty; and
(2) In a hold space flooded to the summer load draft of the vessel.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by USCG-2014-0688, 79 FR 58285, Sept. 29, 2014]
§ 154.471 Design criteria.
(a) The cargo tank support system must be designed:
(1) For the loads in § 154.406(a);
(2) To not exceed the allowable stress under this part at a static angle of heel of 30°;
(3) To withstand a collision force equal to at least one-half the weight of the cargo tank and cargo from
forward and one-quarter the weight of the cargo tank and cargo from aft; and
(4) For the largest resulting acceleration in Figure 1, including rotational and translation effects.
(b) The cargo tank support design loads in paragraph (a) of this section may be analyzed separately.
46 CFR 154.471(b) (enhanced display)
page 50 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.476
§ 154.476 Cargo transfer devices and means.
(a) If a cargo pump in a cargo tank is not accessible for repair when the cargo tank is in use, the cargo tank
must have an additional means of cargo transfer, such as another pump or gas pressurization.
(b) If cargo is transferred by gas pressurization, the pressurizing line must have a safety relief valve that is set
at less than 90 percent of the tank relief valve setting.
CARGO AND PROCESS PIPING SYSTEMS
§ 154.500 Cargo and process piping standards.
The cargo liquid and vapor piping and process piping systems must meet the requirements in §§ 154.503 through
154.562, Subparts 56.01 through 56.35, §§ 56.50-20 and 56.50-105, and Subparts 56.60 through 56.97 of this
chapter.
§ 154.503 Piping and piping system components: Protection from movement.
Where thermal movement and movements of the cargo tank and the hull structure may cause stresses that exceed
the design stresses, the piping and piping system components and cargo tanks must be protected from movement
by:
(a) Offsets;
(b) Loops;
(c) Bends;
(d) Mechanical expansion joints including:
(1) Bellows;
(2) Slip joints;
(3) Ball joints; or
(e) Other means specially approved by the Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.506 Mechanical expansion joint: Limits in a piping system.
Mechanical expansion joints in a piping system outside of a cargo tank:
(a) May be installed only if offsets, loops or bends cannot be installed due to limited space or piping
arrangement;
(b) Must be a bellows type; and
(c) Must not have insulation or a cover unless necessary to prevent damage.
46 CFR 154.506(c) (enhanced display)
page 51 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.512
§ 154.512 Piping: Thermal isolation.
Low temperature piping must be thermally isolated from any adjacent hull structure to prevent the temperature of
that structure from dropping below the minimum temperature for the hull material under § 154.170.
§ 154.514 Piping: Electrical bonding.
(a) Cargo tanks or piping that are separated from the hull structure by thermal isolation must be electrically
bonded to the hull structure by a method under paragraph (c) of this section.
(b) A pipe joint or a hose connection fitting that has a gasket must be electrically bonded by a method under
paragraph (c) of this section that bonds:
(1) Both sides of the connection to the hull structure; or
(2) Each side of the connection to the other side.
(c) An electrical bond must be made by at least one of the following methods:
(1) A metal bonding strap attached by welding or bolting.
(2) Two or more bolts that give metal to metal contact between the bolts and the parts to be bonded.
(3) Metal to metal contact between adjacent parts under designed operating conditions.
§ 154.516 Piping: Hull protection.
A vessel's hull must be protected from low temperature liquid leakage by a drip pan, or other means specially
approved by the Commandant (CG-ENG), at:
(a) Each piping connection dismantled on a routine basis;
(b) Cargo discharge and loading manifolds; and
(c) Pump seals.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.517 Piping: Liquid pressure relief.
The cargo loading and discharge crossover headers, cargo hoses, and cargo loading arms must have means to
relieve cargo pressure and to remove liquid cargo.
§ 154.519 Piping relief valves.
(a) The liquid relief valve that protects the cargo piping system from liquid pressure exceeding the design
pressure must discharge into:
(1) A cargo tank; or
(2) A cargo vent mast if that vent mast has a means for the detection and removal of the liquid cargo
that is specially approved by the Commandant (CG-ENG).
(b) A relief valve on a cargo pump that protects the cargo piping system must discharge into the pump
suction.
46 CFR 154.519(b) (enhanced display)
page 52 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.520
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.520 Piping calculations.
A piping system must be designed to meet the allowable stress values under § 56.07-10 of this chapter and, if the
design temperature is −110 °C (−166 °F) or lower, the stress analysis must be specially approved by the
Commandant (CG-ENG) and must include:
(a) Pipe weight loads;
(b) Acceleration loads;
(c) Internal pressure loads;
(d) Thermal loads; and
(e) Loads from the hull.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.522 Materials for piping.
(a) The materials for piping systems must meet § 154.625 for the minimum design temperature of the piping,
except the material for open ended vent piping may be specially approved by the Commandant (CG-ENG)
if:
(1) The temperature of the cargo at the pressure relief valve setting is −55 °C (−67 °F) or warmer; and
(2) Liquid cannot discharge to the vent piping.
(b) Materials for piping outside the cargo tanks must have a melting point of at least 925 °C (1697 °F), except
for short lengths of pipes with fire resisting insulation that are attached to the cargo tanks.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by USCG-2014-0688, 79 FR 58285, Sept. 29, 2014]
§ 154.524 Piping joints: Welded and screwed couplings.
Pipe lengths without flanges must be joined by one of the following:
(a) A butt welded joint with complete penetration at the weld root except that for design temperatures colder
than −10 °C (14 °F) the butt weld must be double welded or must be welded using:
(1) A backing ring that for design pressures greater than 979 kPa gauge (142 psig) must be removed
after the weld is completed;
(2) A consumable insert; or
(3) An inert gas back-up on the first weld pass.
(b) A slip-on welded joint with sleeves and attachment welds is allowed for an open ended pipe with an
external diameter of 50 mm (2 in.) or less and a design temperature of −55 °C (−67 °F), or warmer.
(c) A socket weld fitting with attachment welds is allowed for pipe with an external diameter of 50 mm (2 in.)
or less and a design temperature of −55 °C (−67 °F) or warmer.
46 CFR 154.524(c) (enhanced display)
page 53 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.524(d)
(d) Screwed couplings are allowed for instrumentation and control piping that meets § 56.30-20 and §
56.50-105 (a)(4) and (b)(4) of this chapter.
(e) A method or fitting specially approved by the Commandant (CG-ENG).
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.526 Piping joints: Flange connection.
Flange connections for pipe joints must meet § 56.30-10 and § 56.50-105 (a)(4) and (b)(4) of this chapter.
§ 154.528 Piping joints: Flange type.
(a) A flange must be one of the following types:
(1) Welding neck.
(2) Slip-on.
(3) Socket weld.
(b) If the piping is designed for a temperature between −10 °C (14 °F) and −55 °C (−67 °F), the pipe flange
may be a:
(1) Slip-on type, if the nominal pipe size is 100 mm (4 in.) or less;
(2) Socket weld, if the nominal pipe size is 50 mm (2 in.) or less; or
(3) Welding neck.
(c) If the piping is designed for a temperature lower than −55 °C (−67 °F), the pipe flange must be a welding
neck type.
§ 154.530 Valves: Cargo tank MARVS 69 kPa gauge (10 psig) or lower.
(a) Except those connections for tank safety relief valves and for liquid level gauging devices other than those
under §§ 154.536 and 154.1310, liquid and vapor connections on a cargo tank with a MARVS of 69 kPa
gauge (10 psig) or lower must have shut-off valves that—
(1) Are located as close to the tank as practical;
(2) Are capable of local manual operation; and
(3) May be remotely controlled.
(b) The cargo piping system for a cargo tank with a MARVS of 69 kPa gauge (10 psig) or lower must have at
least one remotely controlled quick-closing shut-off valve for closing liquid and vapor piping between
vessel and shore that meets §§ 154.540 and 154.544.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]
§ 154.532 Valves: Cargo tank MARVS greater than 69 kPa gauge (10 psig).
(a) Except connections for tank safety relief valves and except for liquid level gauging devices other than
those under §§ 154.536 and 154.1310, liquid and vapor connections on a cargo tank with a MARVS
greater than 69 kPa gauge (10 psig) must have, as close to the tank as practical, a:
46 CFR 154.532(a) (enhanced display)
page 54 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.532(a)(1)
(1) Stop valve capable of local manual operation; and
(2) A remotely controlled quick-closing shut-off valve.
(b) If the nominal pipe size of a liquid or vapor connection is less than 50 mm (2 in.), an excess flow valve
may be substituted for the quick-closing valve under paragraph (a) of this section.
(c) One valve may be substituted for the manual controlled stop valve and the remotely controlled quickclosing shut-off valve required under paragraph (a) of this section if that valve:
(1) Meets §§ 154.540 and 154.544; and
(2) Is capable of local manual operation.
§ 154.534 Cargo pumps and cargo compressors.
Cargo pumps and cargo compressors must shut-down automatically when the quick-closing shut-off valves under
§§ 154.530 and 154.532 are closed by the emergency shut-down system required under § 154.540.
§ 154.536 Cargo tank gauging and measuring connections.
Unless the outward flow from a cargo tank is less than the flow through a circular hole of 1.4 mm (0.055 in.) in
diameter, cargo tank connections for gauging or measuring devices must have the excess flow, shut-off, or quickclosing shut-off valves under § 154.530 or § 154.532.
§ 154.538 Cargo transfer connection.
A cargo transfer connection must have a:
(a) Remotely controlled quick-closing shut-off valve that meets §§ 154.540 and 154.544; or
(b) Blank flange.
§ 154.540 Quick-closing shut-off valves: Emergency shut-down system.
The quick-closing shut-off valves under §§ 154.530, 154.532, and 154.538 must have an emergency shut-down
system that:
(a) Closes all the valves;
(b) Is actuated by a single control in at least two locations remote from the quick-closing valves;
(c) Is actuated by a single control in each cargo control station under § 154.320; and
(d) Has fusible elements at each tank dome and cargo loading and discharge manifold that melt between 98
°C (208 °F) and 104 °C (220 °F) and actuate the emergency shut-down system.
§ 154.544 Quick-closing shut-off valves.
The quick-closing shut-off valve under §§ 154.530, 154.532 and 154.538 must:
(a) Be a shut-off valve;
(b) Close from the time of actuation in 30 seconds or less;
(c) Be the fail-closed type; and
46 CFR 154.544(c) (enhanced display)
page 55 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.544(d)
(d) Be capable of local manual closing.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 77-069, 52 FR 31630, Aug. 21, 1987]
§ 154.546 Excess flow valve: Closing flow.
(a) The rated closing flow of vapor or liquid cargo for an excess flow valve must be specially approved by the
Commandant (CG-ENG).
(b) An excess flow valve allowed under § 154.532(b) must close automatically at the rated closing flow.
[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]
§ 154.548 Cargo piping: Flow capacity.
Piping with an excess flow valve must have a vapor or liquid flow capacity that is greater than the rated closing flow
under § 154.546.
§ 154.550 Excess flow valve: Bypass.
If the excess flow valve allowed under § 154.532(b) has a bypass, the bypass must be of 1.0 mm (0.0394 in.) or less
in diameter.
CARGO HOSE
§ 154.551 Cargo hose: General.
Each of the vessel's liquid and vapor cargo hose for loading or discharging cargo must meet §§ 154.552 through
154.562.
§ 154.552 Cargo hose: Compatibility.
Liquid and vapor cargo hoses must:
(a) Not chemically react with the cargo; and
(b) Withstand design temperature.
§ 154.554 Cargo hose: Bursting pressure.
Cargo hose that may be exposed to the pressure in the cargo tank, the cargo pump discharge, or the vapor
compressor discharge must have a bursting pressure of at least five times the maximum working pressure on the
hose during cargo transfer.
§ 154.556 Cargo hose: Maximum working pressure.
A cargo hose must have a maximum working pressure not less than the maximum pressure to which it may be
subjected and at least 1034 kPa gauge (150 psig).
46 CFR 154.556 (enhanced display)
page 56 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.558
§ 154.558 Cargo hose: Marking.
Each cargo hose must be marked with the:
(a) Maximum working pressure; and
(b) Minimum service temperature for service at other than ambient temperature.
§ 154.560 Cargo hose: Prototype test.
(a) Each cargo hose must be of a type that passes a prototype test at a pressure of at least five times its
maximum working pressure at or below the minimum service temperature.
(b) Each cargo hose must not be the hose used in the prototype test.
§ 154.562 Cargo hose: Hydrostatic test.
Each cargo hose must pass a hydrostatic pressure test at ambient temperature of at least one and a half times its
specified maximum working pressure but not more than two-fifths its bursting pressure.
MATERIALS
§ 154.605 Toughness test.
(a) Each toughness test under §§ 154.610 through 154.625 must meet Subpart 54.05 of this chapter.
(b) If subsize test specimens are used for the Charpy V-notch toughness test, the Charpy V-notch energy
must meet Table 54.05-20 (a) of this chapter.
§ 154.610 Design temperature not colder than 0 °C (32 °F).
Materials for cargo tanks for a design temperature not colder than 0 °C (32 °F) must meet the following:
(a) The tank materials must meet §§ 54.25-1 and 54.25-3 of this chapter.
(b) Plates, forgings, rolled and forged bars and shapes must be carbon manganese steel or other material
allowed under §§ 154.615, 154.620, and 154.625.
(c) Plates must be normalized or quenched and tempered and where the thickness exceeds 20 mm (0.787
in.), made with fine grain practice, austenitic grain size of five or finer. A control rolling procedure may be
substituted for normalizing if specially approved by the Commandant (CG-ENG). Plate for an independent
tank type C must also meet the requirements of ASTM A 20 (incorporated by reference, see § 154.1) and
§ 54.01-18(b)(5) of this chapter.
(d) For integral and independent type A tanks, the American Bureau of Shipping's grade D not exceeding 20
mm (0.787 in.) in thickness, and Grade E hull structural steel are allowed if the steel meets § 54.05-10 of
this chapter.
(e) The tensile properties under paragraph (a) of this section must be determined for:
(1) Each plate as rolled; and
(2) Each five short ton batch of forgings, forged or rolled fittings, and forged or rolled bars and shapes.
46 CFR 154.610(e)(2) (enhanced display)
page 57 of 102
46 CFR Part 154 (up to date as of 6/03/2024)
Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases
46 CFR 154.610(f)
(f) The specified yield strength must not exceed 637 MPa (92.43 Ksi) and when it exceeds 490 MPa (71.10
Ksi), the hardness of the weld and the heat affected zone must be specially approved by the Commandant
(CG-ENG).
(g) The Charpy V-notch impact energy must be determined for:
(1) Each plate as rolled; and
(2) Each five short ton batch of forgings, forged or rolled fittings and rolled or forged bars and shapes.
(h) The orientation and required impact energy of a 10 mm × 10 mm (0.394 in. × 0.394 in.) Charpy V-notch
specimen must be:
(1) For plates; transverse specimen and 27.4 J (20 ft-lbs); and
(2) For forgings, forged and rolled fittings and rolled and forged bars: longitudinal specimen and 41.1 J
(30 ft-lbs).
(i)
The test temperature of the Charpy V-notch specimens is as follows:
Material Thickness
Test Temperature
t≤20 mm (0.788 in.)
0 °C (32 °F)
20| File Type | application/pdf |
| File Modified | 0000-00-00 |
| File Created | 0000-00-00 |