46 C.F.R. § 154.447

Current through May 31, 2024

Section 154.447 - Allowable stress

(a) An independent tank type B designed from bodies of revolution must have allowable stresses determined by the following formulae:

[SIGMA]_m[LESS THAN EQUAL TO]f

[SIGMA]_L[LESS THAN EQUAL TO]1.5 f

[SIGMA]_b[LESS THAN EQUAL TO]1.5 F

[SIGMA]_L + [SIGMA]_b[LESS THAN EQUAL TO]1.5 F

[SIGMA]_m + [SIGMA]_b[LESS THAN EQUAL TO]1.5 F

where:

[SIGMA]_m = equivalent primary general membrane stress

See Appendix A for equivalent stress.

[SIGMA]_L = equivalent primary local membrane stress⁴

[SIGMA]_b = equivalent primary bending stress⁴

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 manganese steel values	Austenitic steel values	Aluminum alloy values
Stress factors:
A	4.0	4.0	4.0
B	2.0	1.6	1.5
C	3.0	3.0	3.0
D	1.5	1.5	1.5

(b) An independent tank type B designed from plane surfaces must have allowable stresses specially approved by the Commandant (CG-ENG).

46 C.F.R. §154.447

CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983