Notes:Above t=D/6 we need to consider theories of failure,effect of f atigue and thermal stress

Minimum pipe thickness calculation based on B31.3

Pressure in psig P=

Outside diameter in inch D=

Allowable stress in psi S=(Can take from CAESAR)

Quality Factor E=

Weld joint strength reduction factor W=

Coefficient Y=

If P/SE less than /equal to 0.385 proceed further :P/SE

t min=)(2 PYSEW

PD

+ inch=

Corrosion Allowance in inch c=

T=tmin+c in inch=

Mill tolerance of 12.5%

Required minimum thickness=1.125XT in inch=

Above thickness valid iff required thickness less than D/6

Chart1:

Single Buttt Weld:

E=0.8

E=0.9 Spot RT

E=1.0 Full RT

Double Buttt Weld:

E=0.85

E=0.9 Spot RT

E=1.0 Full RT

Chart2:W: