example of pipe wall thickness calc
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Example of Pipe Wall Thickness CalculationTRANSCRIPT
Example:A 12" (300 mm) NB pipe has an internal maximum operating pressure of 500 psig (35kg / cm2g) and temperature of 6750F. The material of construction o f the pipe is seamless carbon steel to ASTM A106 Gr B. The recommended corrosion allowance is 1/8" (3mm). Calculate the thickness of pipe as per ASME B 31.3 and select the proper schedule. Tm = P = 10% higher than the MWP = 1.1 x 500 = 550 psigD = 12.75" (OD of 12" NB pipe)Design temperature = 675 + 25 = 7000 FS = 16500 psi (Refer ASME B 31.3 Appendix A Table A-1)E = 1 (Joint Quality factor. Refer ASME B31.3, Appendix A Table A-1B) Y = 0.4 (Refer Table 304.1.1)C = 0.125" (Specified) = 0.2097 + 0.125 = 0.335Hence, considering the mill tolerance of 12.5%, the nominal thickness for a min. thickness of 0.335" will be In practice we will specify SCH 40 pipe which has a nominal wall thickness of 0.406" and minimum 0.355" (0.406x0.875).