(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. ---------------------------------------------------------------------------[sigma]m<=f [sigma]L<=1.5 f [sigma]b<=1.5 F [sigma]L + [sigma]b<=1.5 F [sigma]m + [sigma]b<=1.5 F where: [sigma]m = equivalent primary general membrane stress \4\---------------------------------------------------------------------------
\4\ See Appendix A for equivalent stress.--------------------------------------------------------------------------- [sigma]L = equivalent primary local membrane stress \4\[sigma]b = equivalent primary bending stress \4\f = the lesser of ([sigma]B/A) or ([sigma]Y/B)F = the lesser of ([sigma]B/C) or ([sigma]Y/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 (CG-ENG). [CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]