Pipe Thickness Calculation for Underground Piping

What diameter?

8" NPS

Polythene, polypropylene, cement-lined mild steel or malleable iron will be suitable for systems connected to potable water. One might use non-coated mild steel for non-potable water.

First select the preferred materials and then select the appropriate pressure rating from published tables.

• 1^st the thickness of pipe wall and rating shall be calculated depending on the internal pressure by selecting a suitable section of piping code like ASME B31.4 (liquid pipeline) or ASME B31.8 (Gas pipeline).

• 2^nd the calculated thickness shall be checked for external pressure.

• 3^rd to define the external pressure, you are kindly requested to read Chapter 2 'External Loads' of handbook "Buried Pipe Design".

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GA to Abdel!

I couldn't have said it any better or more concise!

Have a great sunny day!

(BTW, we're in a record-setting heat wave here in upstate NY for the past week.....hit a Record high of 103 F yesterday.....not exactly Saudia Arabia, Kuwait or Iraq, but with high levels of Humidity, UV and Ozone it'd melt (or kill) you just the same!)

thank you abdel.

we had done the thickness calculation based on internal pressure. we did it that by considering ASME B31.3 code only and now proceeding to find thickness based on external pressure. But as u said we can use ASME B31.4, we now have a doubt whether fire fighting lines come under ASME B31.3 or ASME B31.4? sir,can u make it clear?

ASME B31.3 can be used to cover all piping systems located in a refinery (see definition of refinery), and it is considered as more restrict compared with ASME B31.4. Try to use ASME B31.4 and see the differences.

ok.. thank you