SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES

• Citation: 46 CFR Part 154
• Sections: 247

§ 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 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

UL No. 783-79 Standard for Safety, Electric Flashlights for Use in Hazardous Locations, Class 1, Groups C and D, 1979.

§ 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 m

2 (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.

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 (P o ) 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

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;

(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.

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

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

(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.

(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 m

3 (88,200 ft

3 ) 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:

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.

§ 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

(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).

§ 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.

§ 154.32 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—

(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.

§ 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.

Appendix A Appendix A to Part 154—Equivalent Stress

I. Equivalent stress (σ c) is calculated by the following formula or another formula specially approved by the Commandant (CG-522) as equivalent to the following:

where:

σ x = total normal stress in “x” direction.

σ y = total normal stress in “y” direction.

τ xy = total shear stress in “xy” plane.

II. When the static and dynamic stresses are calculated separately, the total stresses in paragraph I are calculated from the following formulae or another formulae specially approved by the Commandant (CG-522) as equivalent to the following:

III. Each dynamic and static stress is determined from its acceleration component and its hull strain component from hull deflection and torsion.

Appendix B Appendix B to Part 154—Stress Analyses Definitions

The following are the standard definitions of stresses for the analysis of an independent tank type B:

Normal stress means the component of stress normal to the plane of reference.

Membrane stress means the component of normal stress that is uniformly distributed and equal to the average value of the stress across the thickness of the section under consideration.

Bending stress means the variable stress across the thickness of the section under consideration, after the subtraction of the membrane stress.

Shear stress means the component of the stress acting in the plane of reference.

Primary stress means the stress produced by the imposed loading that is necessary to balance the external forces and moments. (The basic characteristic of a primary stress is that it is not self-limiting. Primary stresses that considerably exceed the yield strength result in failure or at least in gross deformations.)

Primary general membrane stress means the primary membrane stress that is so distributed in the structure that no redistribution of load occurs as a result of yielding.

Primary local membrane stress means the resulting stress from both a membrane stress, caused by pressure or other mechanical loading, and a primary or a discontinuity effect that produces excessive distortion in the transfer of loads to other portions of the structure. (The resulting stress is a primary local membrane stress although it has some characteristics of a secondary stress.) A stress region is local if:

where:

S 1 = distance in the meridional direction over which the equivalent stress exceeds 1.1 f.

S 2 = distance in the meridional direction to another region where the limits for primary general membrane stress are exceeded.

R = mean radius of the vessel.

t = wall thickness of the vessel at the location where the primary general membrane stress limit is exceeded.

f = allowable primary general membrane stress.

Secondary stress means a normal stress or shear stress caused by constraints of adjacent parts or by self-constraint of a structure. The basic characteristic of a secondary stress is that it is self-limiting. Local yielding and minor distortions can satisfy the conditions that cause the stress to occur.

§ 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.

§ 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:

(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.

§ 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:

(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.

§ 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

Steel 1 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

12.5<t≤25.5 mm (1 in.)

D

>25.5 mm (1 in.)

E

−25 °C (−13 °F)

t≤112.5 mm ( 1 ⁄ 2 in.)

D

>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.

§ 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.

§ 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

(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).

§ 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

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.

(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.

§ 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.

§ 154.200 Stability requirements: General.

Each vessel must meet the applicable requirements in subchapter S of this chapter.

§ 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).

§ 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:

(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).

§ 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.

(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.

§ 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:

(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.

§ 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).

(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).

§ 154.401 Definitions.

As used in §§ 154.440 and 154.447:

“σ Y ” means the minimum yield strength of the tank material, including weld metal, at room temperature.

“σ B ” means minimum tensile strength of the tank material, including weld metals, at room temperature.

§ 154.405 Design vapor pressure (P o ) of a cargo tank.

(a) The design vapor pressure (P o ) of a cargo tank must be equal to or greater than the MARVS.

(b) The P o 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 P o of a cargo tank may be exceeded under harbor conditions if specially approved by the Commandant (CG-ENG).

§ 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.

(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 (CG-ENG).

§ 154.407 Cargo tank internal pressure head.

(a) For the calculation required under § 154.406(a)(1) and (b), the internal pressure head (h eq ), must be determined from the following formula:

h eq = 10 P o + (h gd ) max

where:

h gd (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/m

3 ) at the design temperature.

(b) The (h gd ) max is determined for the β direction, on the ellipse in Figure 1, which gives the maximum value for h gd .

(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.

§ 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 10

8 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:

(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.

(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.

§ 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).

§ 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.