Page 107 - Pressure Vessel Design Manual

88 Pressure Vessel Design Manual

e Maximum longitudinal compressive stress, Ob. Factor of Safety
With external pressure. e
F.S. = 1.5-3.0
-W 4M P,Do
Ob=----- Tolerances per AWWA D-100
nD,t nDEt 4t

With internal pressure. e = 0.046rnax
1 = 4. JRotmax
PiD,
-W 4M +-
Ob=---
nD,t nR:t 4t
e Radius of gyration, r.

Table 2-14
Formulas for Cylinders
Short Cyilnder intermediate Cylinder Long Cylinder

L < Lc

cA0 R'
1.72 - <-< 2.30 - bo I! I
L > Lc

3etermination of Attribute

Sritical External Pressure, P,
2.5
2.6E(k)
P, =

Sritical Axial Stress, uCcr

Sritical Buckling Load, P,,
pc, = UcP