Loading (50 kb)...'
(continued)
(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.
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(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.
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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 (G-MSO).
[CGD 74–289, 44 FR 26009, May 3, 1979, as amended by CGD 82–063b, 48 FR 4782, Feb. 3, 1983]
Cargo Containment Systems
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§ 154.401 Definitions.
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As used in §§154.440 and 154.447:
“sY” means the minimum yield strength of the tank material, including weld metal, at room temperature.
“sB” means minimum tensile strength of the tank material, including weld metals, at room temperature.
§ 154.405 Design vapor pressure (Po) of a cargo tank.
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(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 (G-MSO).
[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.
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(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 that -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 (G-MSO).
[CGD 74–289, 44 FR 26009, May 3, 1979, as amended by CGD 82–063b, 48 FR 4782, Feb. 3, 1983]
§ 154.407 Cargo tank internal pressure head.
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(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)=aß Zß Y;
where:
aß=dimensionless acceleration relative to the acceleration of gravity resulting from gravitational and dynamic loads in the ß direction (see figure 1);
Zß=largest liquid height (m) above the point where the pressure is to be determined in the ß direction (see figure 2);
Y=maximum specific weight of the cargo (t/m 3 ) at the design temperature.
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(b) The (hgd) max is determined for the ß 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.
§ 154.408 Cargo tank external pressure load.
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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.
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(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 (G-MSO) 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:
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(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.
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(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.
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(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 (G-MSO).
(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 (G-MSO).
[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.
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For the calculations required under §154.406(a)(4), the following determined loads must be specially approved by the Commandant (G-MSO):
(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.
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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
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§ 154.418 General.
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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 (G-MSO).
[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.
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The Po of an integral tank must not exceed 24.5 kPa gauge (3.55 psig) unless special approval by the Commandant (G-MSO) 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.
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(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.
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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
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§ 154.425 General.
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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 (G-MSO).
[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.
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The Po of a membrane tank must not exceed 24.5 kPa gauge (3.55 psig) unless special approval by the Commandant (G-MSO) 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]
§ 154.427 Membrane tank system design.
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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.
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The membrane tank and the supporting insulation must have allowable stresses that are specially approved by the Commandant (G-MSO).
[CGD 74–289, 44 FR 26009, May 3, 1979, as amended by CGD 82–063b, 48 FR 4782, Feb. 3, 1983]
§ 154.429 Calculations.
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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.
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(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 (G-MSO).
[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.
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(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).
(b) Analyzed data of a model test for the primary and secondary barrier of the membrane tank must be submitted to the Commandant (G-MSO).
[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.
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The support system of a membrane tank must allow for thermal and physical expansion and contraction of the tank.
Semi-Membrane Tanks
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§ 154.435 General.
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(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 (G-MSO).
(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.
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The Po of a semi-membrane tank must not exceed 24.5 kPa gauge (3.55 psig) unless special approval by the Commandant (G-MSO) 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
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§ 154.437 General.
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An independent tank type A must meet §154.438 through §154.440.
§ 154.438 Design vapor pressure.
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(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 (G-MSO).
[CGD 74–289, 44 FR 26009, May 3, 1979, as amended by CGD 82–063b, 48 FR 4782, Feb. 3, 1983]
§ 154.439 Tank design.
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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.
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(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 sB/2.66 or sY/1.33, whichever is less; and
(2) For other materials, be specially approved by the Commandant (G-MSO).
(b) A greater allowable stress than required in paragraph (a)(1) of this section may be specially approved by the Commandant (G-MSO) if the equivalent stress (sc) 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
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§ 154.444 General.
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An independent tank type B must be designed to meet §§154.445 through 154.449.
§ 154.445 Design vapor pressure.
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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.
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An independent tank type B must meet the calculations under §154.448.
§ 154.447 Allowable stress.
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(a) An independent tank type B designed from bodies of revolution must have allowable stresses 3 determined by the following formulae:
3 See Appendix B for stress analyses definitions.
sm= f
sL= 1.5 f
sb= 1.5 F
sL + sb= 1.5 F
sm + sb= 1.5 F
where:
sm=equivalent primary general membrane stress 4
4 See Appendix A for equivalent stress.
sL=equivalent primary local membrane stress 4
sb=equivalent primary bending stress 4
f=the lesser of (sB/A) or (sY/B)
F=the lesser of (sB/C) or (sY/D)
A, B, C, and D=stress factors in Table 2.
Table 2_Values for Stress Factors
------------------------------------------------------------------------
Nickel
steel and
carbon Austenitic Aluminum
manganese steel alloy
steel values values
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 (G-MSO).
[CGD 74–289, 44 FR 26009, May 3, 1979, as amended by CGD 82–063b, 48 FR 4782, Feb. 3, 1983]
§ 154.448 Calculations.
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The following calculations for an independent tank type B must be specially approved by the Commandant (G-MSO):
(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.
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The following analyzed data of a model test of structural elements for independent tank type B must be submitted to the Commandant (G-MSO) 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
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§ 154.450 General.
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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.
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The Po (kPa) of an independent tank type C must be calculated by the following formula:
Po=196+AC(?)3/2
where:
A=1.813 (sm/?sA) 2 ;
sm=design primary membrane stress;
?sA=(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;
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
?=the specific gravity of the cargo.
§ 154.452 External pressure.
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The design external pressure, Pe, for an independent tank type C must be calculated by the following formula:
Pe=P1+P2+P3+P4
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.
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If the Commandant (G-MSO) 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 can not 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]
Secondary Barrier
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§ 154.459 General.
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(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 (G-MSO) 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 (G-MSO) 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 (G-MSO).
(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.
Table 3_Secondary Barriers for Tanks
----------------------------------------------------------------------------------------------------------------
Cargo temperature (T) at atmospheric pressure
---------------------------------------------------------------------------
Tank type T<-10 °C (14
T>=-10 °C (14 °F)>=55 °C (-67 T<-55 °C (-67
°F) °F) °F)
----------------------------------------------------------------------------------------------------------------
Integral............................ No secondary barrier Tank type not usually Tank type not allowed.
required. allowed \1\.
Membrane............................ ......do................ Complete secondary Complete secondary
barrier \1\. barrier.
Semi-membrane....................... ......do................ ......do............... Do.
Independent:
Type A............................ ......do................ ......do............... Do.
Type B............................ ......do................ Partial secondary Partial secondary
barrier \1\. barrier.
Type C............................ ......do................ No secondary barrier No secondary barrier
required. required.
----------------------------------------------------------------------------------------------------------------
\1\ 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.
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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
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§ 154.465 General.
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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.
§ 154.466 Design criteria.
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(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.
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The following insulation information must be submitted for special approval by the Commandant (G-MSO):
(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.
(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
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§ 154.470 General.
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(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 antiflotation 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.
§ 154.471 Design criteria.
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(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.
§ 154.476 Cargo transfer devices and means.
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(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
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§ 154.500 Cargo and process piping standards.
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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.
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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 (G-MSO).
[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.
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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.
§ 154.512 Piping: Thermal isolation.
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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.
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(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.
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A vessel's hull must be protected from low temperature liquid leakage by a drip pan, or other means specially approved by the Commandant (G-MSO), 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.
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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.
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(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 (G-MSO).
(b) A relief valve on a cargo pump that protects the cargo piping system must discharge into the pump suction.
[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.
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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 (G-MSO) 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.
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(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 (G-MSO) if:
(1) The temperature of the cargo at the pressure relief valve setting is -55 °C (-67 °F) or warmer; and
(2) Liquid can not 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.
§ 154.524 Piping joints: Welded and screwed couplings.
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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.
(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 (G-MSO).
[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.
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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.
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(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.
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(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).
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(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:
(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 quick-closing 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.
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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.
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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 quick-closing shut-off valves under §154.530 or §154.532.
§ 154.538 Cargo transfer connection.
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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.
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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.
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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
(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.
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(a) The rated closing flow of vapor or liquid cargo for an excess flow valve must be specially approved by the Commandant (G-MSO).
(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.
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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.
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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
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§ 154.551 Cargo hose: General.
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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.
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Liquid and vapor cargo hoses must:
(a) Not chemically react with the cargo; and
(b) Withstand design temperature.
§ 154.554 Cargo hose: Bursting pressure.
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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.
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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).
§ 154.558 Cargo hose: Marking.
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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.
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(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.
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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
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§ 154.605 Toughness test.
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(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).
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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 (G-MSO). 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.
(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 (G-MSO).
(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[le]20 mm (0.788 in.)......................... 0 °C (32 °F)
20< t<30 mm (1.182 in.).................. -20 °C (-4 °F)
30< t<40 mm (1.576 in.).................. -40 °C (-40 °F)
------------------------------------------------------------------------
[CGD 74–289, 44 FR 26009, May 3, 1979, as amended by CGD 82–063b, 48 FR 4782, Feb. 3, 1983; USCG–1999–5151, 64 FR 67183, Dec. 1, 1999]
§ 154.615 Design temperature below 0 °C (32 °F) and down to -55 °C (-67 °F).
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Plates, forgings, forged or rolled or forged bars and shapes for cargo tanks and secondary barriers for a design temperature below 0 °C (32 °F) and down to -55 °C (-67 °F) must meet §54.25–10 of this chapter.
§ 154.620 Design temperature below -55 °C (-67 °F) and down to -165 °C (-265 °F).
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Plates, forgings and forged or rolled fittings, and rolled, forged or extruded bars and shapes for cargo tanks, secondary barriers, and process pressure vessels for a design temperature below -55 °C (-67 °F) and down to -165 °C (-265 °F) must:
(a) Meet §54.25–10(b)(2), §54.25–15, or §54.25–20 of this chapter; or
(b) Be of an aluminum alloy that is specially approved by the Commandant (G-MSO).
[CGD 74–289, 44 FR 26009, May 3, 1979, as amended by CGD 82–063b, 48 FR 4782, Feb. 3, 1983]
§ 154.625 Design temperature below 0 °C (32 °F) and down to -165 °C (-265 °F).
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Pipes, tubes, forgings, castings, bolting, and nuts for cargo and process piping for a design temperature below 0 °C (32 °F) and down to -165 °C (-265 °F) must meet §56.50–105 of this chapter.
§ 154.630 Cargo tank material.
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(a) If a material of a cargo tank is not listed in §§154.610, 154.615 or §154.620, the allowable stress of that material must be specially approved by the Commandant (G-MSO).
(b) For cargo tanks of aluminum alloys with welded connections, the minimum tensile strength (sB) for the calculations under §154.440, §154.447 and §154.450 must be the minimum tensile strength of the alloy in the annealed condition.
(c) Increased yield strength and tensile strength of a material at low temperature for independent tanks type A, B, and C must be specially approved by the Commandant (G-MSO).
[CGD 74–289, 44 FR 26009, May 3, 1979, as amended by CGD 82–063b, 48 FR 4782, Feb. 3, 1983]
Construction
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§ 154.650 Cargo tank and process pressure vessel welding.
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(a) Cargo tank and process pressure vessel welding must meet Subpart 54.05 and Part 57 of this chapter.
(b) Welding consumables used in welding cargo tanks must meet §57.02–4 of this chapter.
(c) Independent tanks must meet the following:
(1) Each welded joint of the shells must be a full penetration butt weld, except dome to shell connections may have full penetration tee welds.
(2) Each nozzle weld must be of the full penetration type, except for small penetrations on domes.
(d) Each welded joint in an independent tank type C or in a process pressure vessel must meet Part 54 of this chapter, except that any backing rings must be removed unless specially approved by the Commandant (G-MSO).
(e) Each welded joint in a membrane tank must meet the quality assurance measures, weld procedure qualification, design details, materials, construction, inspection, and production testing of components developed during the prototype testing program that are specially approved by the Commandant (G-MSO) under this part.
(f) Each welded joint in a semi-membrane tank must meet paragraph (c) or (e) of this section.
[CGD 74–289, 44 FR 26009, May 3, 1979,as amended by CGD 82–063b, 48 FR 4782, Feb. 3, 1983] (continued)