Boiler Codes ASME Shell Thickness

Drum Design Pressure : Stresses due to hydrostatic head shall be taken into account in determining the minimum thickness required unless noted otherwise. Additional stresses imposed by effects other than working pressure or static head that increase the average stress by more than 10% of the allowable working stress shall also be taken into account. These effects include the weight of the component and its contents, and the method of support.

Stress value S : All material used in Pressure part are as per ASME Section II, A material specifications and are selected as per PG-5 to PG-9 of ASME Section-I

Ligament efficiency E : Least of Longitudinal Ligament Efficiency , Circumferential Ligament Efficiency. & Equivalent Longitudinal Ligament Efficiency Of Diagonal Ligament (As per : PG-52.2 ,52.4 )

"Allowance C : Allowance for Structural Stability, Threading Etc =0 Allowance for threading and minimum structural stability is not intended to provide for conditions of misapplied external loads or for mechanical abuse."
Y : a coefficient having values refer table PG-27.4 NOTE-6 ( Page. No. 15 ) For nonferrous materials not listed = 0.4 ,
t=( PR/(SE-(1-Y)P ) +C