API 1102: Doubt on Longitudinal stress calculation 1

[racp12]

I make reference to API 1102 "Steel Pipelines Crossing Railroads and Highways" 6th Edition, April 1993, Appendix B, Uncased design examples, B.1 Highway crossing design.
Under Design information, data for Installation Temperature, T1, Maximum or minimum operating temperature, T2, and the Temperature derating factor, T are not available.

Then, on step g, point 2.2, Equation 10, which is a function of (T2-T1), result for calculation of longitudinal stress is 9,486 psi.

If T2 and T1 are not available, for me it is clear that the difference (T2-T1) is not available. For that reason, I cannot find the way for obtaining that figure of 9,486 psi.

I would appreciate having an explanation for this calculation.

 

[BigInch]

Its just a fake example calculation. Why worry about their values or their answer? Plug your own data in the formula and solve your own problem. That's what I did.

http://virtualpipeline.spaces.msn.com

 

[GregLamberson]

Use a temperature de-rating factor of 1 if your system is operating at 250F or less. Otherwise use:

300F = 0.967
350F = 0.933
400F = 0.900
450F = 0.867

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[GregLamberson]

PS - you'll find the temperature derating factors in table 841.116A on page 35 of the ASME B31.8a-2000 ADDENDA. If you don't have that, just look in 31.8 under "Temperature Derating Factor. T, for Steel Pipe" in the TOC.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com