HDPE pipeline crossing
HDPE pipeline crossing
(OP)
My Client wants me to check if the HDPE pipeline is ok under the earth and vehicle load. Could someone kindly point me to the article, specfications, formulas that I can base my calcualtion on?
Thnaks
Thnaks





RE: HDPE pipeline crossing
RE: HDPE pipeline crossing
www.kwhpipe.ca/Link.aspx?id=1097884
RE: HDPE pipeline crossing
Manufacturer should provide data on allowable loads and then you would need to use an appropriate procedure to determine the imposed loads.
Try Section 3 of the Report "Development of a Pipeline Surface Loading Screening Process & ASsessment of Surface Load Dispensing Methods" CEPA Report 05-44. Available online if you search for it.
RE: HDPE pipeline crossing
RE: HDPE pipeline crossing
Compare hoop stress to PTSV for notch toughness requirements.
Regards,
SNORGY.
RE: HDPE pipeline crossing
Regards,
SNORGY.
RE: HDPE pipeline crossing
RE: HDPE pipeline crossing
In some instances you can test in excess of yield stress, like in class locations 1 and 2 with a liquid test medium, provided you don't exceed 0.2% deviation on a P-V plot.
Regards,
SNORGY.
RE: HDPE pipeline crossing
Up to now, the way I understand is when designing the MAOP based on the SMYS and other factors (F,J,T...), we would need to check against 0.6 SMYS. That is to say, if the pipeline is design for open field and no traffic then F = 0.8 and the other factors are 1. Say if one day someone whats to cross the pipeline, then the location factor may become 0.75. In this case, the MAOP has to adjust in order to make sure that it is ok for 0.6 SMYS. Correct me if my understanding is wrong.
RE: HDPE pipeline crossing
Books worth reading:-
Buried Piping Design by Moser
Structural Mechanics of Buried Pipelines by Watkins et al
RE: HDPE pipeline crossing
The section in the Alberta Regulation to which you refer relates to buried sour gas pipelines, and it is the maximum Design Operating Stress (DOS) level permitted relative to SMYS. However, you *can* hydrostatically test to higher than this level, and indeed as high as 110% SMYS (subject to previously mentioned limitations), if you want. The catch would be that if you want to exceed 100% of SMYS during a hydrostatic test, the ERCB would require a non-routine pipeline license application (as well as the P-V plot referenced in 36 of the Regulation).
The "design factor" to apply in establishing your pressure design thickness boils down to the minimum of FxLxJxT (From CSA Z662-07 Class Locations and the Tables in Clause 4) or that read from the applicable Regulation.
In other words...
DF = MIN [FxLxJxT, F(Regulation)]
Regards,
SNORGY.
RE: HDPE pipeline crossing
Regards,
SNORGY.
RE: HDPE pipeline crossing
You can still hydrotest to a value higher than 100% of yield but it would not be required in this case since the Alberta Regulation requires a hydrotest of only 1.4X the MOP for sour pipelines. Since the MOP can be no more than 0.6x.SMYS then 1.4X the MOP can be no more than 0.84xSMYS. You can certainly test higher if you like, but there is no Regulatory requirement to do so.
RE: HDPE pipeline crossing