46 C.F.R. § 154.459 General.
Title 46 - Shipping
(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. (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]
Title 46: Shipping
PART 154—SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES
Subpart C—Design, Construction and Equipment
Secondary Barrier
§ 154.459 General.
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.
