Dear Experts

I am doing a stress analysis for a buried line (PIG LINE) in code ASME 31.8. My doubt is that as I am using two temperatures maximum and minimum (T1 & T2). When I give recommend in load case Caesar II default shows

• Case 1 (HYD) W+HP
• Case 2 (OPE) W+T1+P1
• Case 3 (OPE) W+T2+P1
• Case 4 (SUS) W+P1
• Case 5 (EXP) L5=L2-L4
• Case 6 (EXP) L6=L3-L4
• Case 7 (EXP) L7=L2-L3

My doubt is that, when case 7 is applicable for buried lines??