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HDD River Crossing Design Factor

HDD River Crossing Design Factor

HDD River Crossing Design Factor

(OP)
I have a good program to design a steel pipeline HDD crossing of a waterbody, which considers the summation of all installation stresses and gives a thumbs up/thumbs down.  My question is: What is the Design Factor (F) used to calculate  operating MAOP/hydrotesting, once successfully in place and tied in.  I looked at ASME B31.8 and it didn't specifically mention HDD crossings; just class locations, fab assemblies, , stations, etc.

RE: HDD River Crossing Design Factor

correct, the location of the crossing or class location is what determines the Design Factor (assuming P = 2St/D (FED)).  if this crossing is for the transportation of petroleum or gas products, then CFR needs to be applied.  also whether onshore or offshore . . . read the CFR scope to ensure proper usage.

try:
TITLE 49--Transportation

Subtitle B--OTHER REGULATIONS RELATING TO TRANSPORTATION

CHAPTER I--PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION

SUBCHAPTER D--PIPELINE SAFETY

PART 192--TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS

at:
http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&tpl=/ecfrbrowse/Title49/49cfr192_main_02.tpl

good luck!
-pmover

RE: HDD River Crossing Design Factor

(OP)
Thanks for your help.  I was thinking that it might be similar to a road crossing or fabricated assembly (pig trap) in a class 1 location.  As you know, ASME B31.8 (gas) gives a design factor F of 0.72 for line pipe in a class 1 area, but reduces it to 0.6 for the pipe used under a road crossing or for a fabrication (more conservative).
I understand you're saying that once the HDD is installed and tied in, it's just like the pipeline itself regarding the D.F. using P=2ST/D *FET.  Best Regards.

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