API RP 1102 Application

[tiz99]

Hi all,

I was wondering if anyone knew the reason that API RP 1102 S1.2 states that: "This practice should not be applied retroactively."

I want to use the Practice for an existing pipeline that needs to be crossed away from a designed crossing. To me this is retroactive application insofar as the pipeline has already been designed and constructed, but I can't see what difference it makes?

Thanks in advance

Tiz

 

[LittleInch]

You can read that two ways.

You can read it like you have OR

What it is trying to say is don't use the latest version to look at a crossing or pipeline installed to an earlier edition or version.

That would be my interpretation when you look at the rest of the section "Neither should it apply to pipelines under contract for construction on or prior to the effective date of this edition."

Unless your crossing is a new road or railway, there are other ways to calculated the effect of a temporary crossing by construction traffic. Do a search in the pipelines forum and you'll find this question answered.

but it will give you a good idea if your pipe is going to be OK.

Just worry more about settlement at the crossing and any shear developed as the pipeline tries to hold the crossing up.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[tiz99]

Hi LittleInch,

Thankyou for your helpful response.

The pipeline was built decades ago, but we do not have the documentation to determine what the existing road crossings were designed to. The pipeline was designed to AS 2885, which suggests the use of API RP 1102 for road or rail crossings.

Other methods that I have considered are the Sprangler method, which I have been told will result in overly-conservative results, and FEA, which I would only consider if there are no simpler options available. I did search the forum and it seems that API RP 1102 is the main method used for these kind of calculations. Unfortunately one of our crossings is < 30deg from the pipeline axis, so FEA may be required since this is outside the scope of API RP 1102. I would be grateful if you have any suggestions that will allow us to avoid this.

Thanks again