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86 Pipeline Rules of Thumb Handbook

Liquid pipelines—ANSI/ASME B31.4 Note: Refer to p. 195.106 of Part 195 Federal Pipeline
Safety Regulations for design factors to be used on offshore
The internal design pressure is determined by using the risers and platform piping and cold worked pipe.
following formula: A typical calculation of the internal design pressure is as
follows:
P = (2 St D) ¥ E F
¥
2
where P = Internal design pressure, lb/in. gauge Pipe: 26≤ OD ¥ 0.3125≤ wt API 5LX X52 ERW
2
S = Speciﬁed minimum yield strength, lb/in. (see Weld joint factor E = 1.0 (see Table 6)
Table 5) Design factor F = 0.72
t = Nominal wall thickness, in.
D = Nominal outside diameter of the pipe, in.
.
,
E = Weld joint factor (see Table 6) P = (2 ¥ 52 000 ¥ 0 3125 26 ) ¥¥1 0 72.
2
F = Design factor of 0.72 P = 900 lb in gauge
.
Table 5
Tabulation of Examples of Allowable Stresses for Reference Use in Piping Systems

Allowable stress values (S) shown in this Table are equal to 0.72 ¥ E (weld joint factor) ¥ speciﬁed minimum yield strength of
the pipe.
Allowable stress values shown are for new pipe of known speciﬁcation. Allowable stress values for new pipe of unknown
speciﬁcation, ASTM A 120 speciﬁcation or used (reclaimed) pipe shall be determined in accordance with 402.3.1.
For some Code computations, particularly with regard to branch connections [see 404.3.1 (d) (3)] and expansion, ﬂexibility,
structural attachments, supports, and restraints (Chapter II, Part 5), the weld joint factor E need not be considered.
For speciﬁed minimum yield strength of other grades in approved speciﬁcations, refer to that particular speciﬁcation.
Allowable stress value for cold worked pipe subsequently heated to 600F (300C) or higher (welding excepted) shall be 75
percent of value listed in Table.
Deﬁnitions for the various types of pipe are given in 400.2.
(Metrics Stress Levels are given in MPa [1 Megapascal = 1 million pascals])
Speciﬁed (S)
Min Yield (E ) Allowable Stress Value
Strength Weld Joint -20F to 250F (-30C to 120C)
Speciﬁcation Grade psi (MPa) Notes Factor psi (MPa)

Seamless
API 5L A25 25,000 (172) (1) 1.00 18,000 (124)
API 5L, ASTM A53, ASTM A106 A 30,000 (207) (1) (2) 1.00 21,600 (149)
API 5L, ASTM A53, ASTM A106 B 35,000 (241) (1) (2) 1.00 25,200 (174)
ASTM A106 C 40,000 (278) (1) (2) 1.00 28,800 (199)
ASTM A524 I 35,000 (241) (1) 1.00 25,200 (174)
ASTM A524 II 30,000 (207) (1) 1.00 21,600 (149)
API 5LU U80 80,000 (551) (1) (4) 1.00 57,600 (397)
API 5LU U100 100,000 (689) (1) (4) 1.00 72,000 (496)
API 5LX X42 42,000 (289) (1) (2) (4) 1.00 30,250 (208)
API 5LX X46 46,000 (317) (1) (2) (4) 1.00 33,100 (228)
API 5LX X52 52,000 (358) (1) (2) (4) 1.00 37,450 (258)
API 5LX X56 56,000 (386) (1) (4) 1.00 40,300 (278)
API 5LX X60 60,000 (413) (1) (4) 1.00 43,200 (298)
API 5LX X65 65,000 (448) (1) (4) 1.00 46,800 (323)
API 5LX X70 70,000 (482) (1) (4) 1.00 50,400 (347)
Furnace Welded-Butt Welded
ASTM A53 25,000 (172) (1) (2) 0.60 10,800 (74)
API 5L Class I & Class II A25 25,000 (172) (1) (2) (3) 0.60 10,800 (74)
API 5L (Bessemer), ASTM A53 (Bessemer) 30,000 (207) (1) (2) (5) 0.60 12,950 (89)
Reproduced from ANSI/ASME Code B31-4-1979, Table 402.3.1(a). Reprinted courtesy of The American Society of Mechanical Engineers.

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