Interpretation Response #PI-74-0128

Interpretation Response Details

State of Colorado
The Public Utilities Commission
500 Columbine Building
1845 Sherman Street
Denver, Colorado 80203

June 24, 1974

Mr., J. C. Thomas, P.E.
Program Manager - Pipeline
Transportation Safety Institute
6500 South MacArthur Boulevard
Oklahoma City, Oklahoma 73125

Dear Jim:

I am writing to you instead of the Washington, D.C. OPS office in hopes that I might get a faster answer than I could through them.

I realize you are probably doing a lot of traveling, and you may get this while you are out of town, but I am hopeful we can still save some time. Should you not have the time to give me an answer, I know you will forward this to Washington, D.C.

A question has come up in our Colorado field operations regarding "Uprating"-- Subpart K. What we would like to have is some sort of definitive statement covering when ,an operator needs to "Uprate" a pipeline by the incremental pressure test steps procedure vs. when he can simply one step pressure “Strength Test” under Subpart J.

We have at least one operator in Colorado who feels that rather than "Uprate" a line under Subpart K, he can merely raise the pressure to a predetermined level and hold an eight-hour test on that line for eight hours and then drop his MAOP down to whatever percentage the Code allows for that particular strength test.

The Code does not specifically say in Subparts J and K when either one of these subparts should be applied to an actual up rating situation.

It appears to us that an operator using a simple strength test to up rate a line is taking the easy way out and is not actually conforming to the Code's intentions. Any help you can give us will be appreciated.

Very truly yours,

THE PUBLIC UTILITIES COMMISSION OF THE STATE OF COLORADO
Ray Richardson
Engineering Analyst

Mr. Ray Richardson
Colorado Public Utilities Commission
500 Columbine Building
1845 Sherman Street
Denver, CO  80203

Dear Mr. Richardson:

This responds to your letter of June 24, 1974, asking, with respect to uprating a pipeline, when an operator must use an incremental pressure test procedure and when the operator may use a one-step pressure test under Subpart J.

Subpart K regulates the uprating of pipelines.  Sections 192.555(e) and 192.557(e), as applicable, require any increase in the maximum allowable operating pressure to be made in increments, except where a pipeline is uprated under section 192.555(d) (1).  Section 192.555(d)(1) applies only to steel pipelines and involves uprating to a hoop stress of 30 percent or more of SMYS and testing in accordance with Subpart J.  In this subpart, the pressure test required for pipelines operated at 30 percent or more of SMYS under section 192.505 is a one-step procedure.

We trust our response is helpful to you.

Sincerely,

Joseph C. Caldwell      
Director                
Office of Pipeline Safety

Regulation Sections