Interpretation Response #PI-78-019
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Department of Transportation
2100 Second Street, S.W.
Washington, D. C. 20590
Recently Louisiana Valve & Fittings Company established a Pipeline Products Division that inventories High Yield Welding Fittings for the oil and gas pipeline companies. We have had numerous discussions with pipeline company personnel regarding their acceptance of material we have in our inventory. The point that is unclear in these discussions is whether a company will accept a fitting that is stencilled with a yield strength below the SMYS required but the detailed metal analysis reports received from the manufacturer indicates the actual yield of the metal is the same or greater than required. Parts 191, 192 & 192 of D.O.T. do not make reference to this point.
Our consensus of opinion is that each individual company or the person responsible for regulation interpretation has their own criteria - in other words some companies will accept material stencilled with a lower yield provided test papers prove the integrity of the fitting while other will not.
I would not be interested in knowing if this question has been posed or if D.O.T. has made any ruling on the subject. Your prompt response will be helpful in future discussions we have with our customers.
Very truly yours,
LOUISIANA VALVE 7 FITTINGS CO., INC.
James H. thompson, Manager
LACALCO Pipeline Products Division
Mr. James H. Thompson, Manager
LAVALCO Pipeline Products Division
P. O. Box 5614
Shreveport, Louisiana 71105
Dear Mr. Thompson:
Your letter of May 12, 1978, and the telephone call to you on June 1, 1978, by Paul Cory, of this office raises the following question:
"If a weld fitting has been manufactured and marked in accordance with an appropriate specification which is listed in 49 CFR Parts 192 and 195, but is found to be made of steel with a higher yield strength than the SMYS to which it was manufactured and marked, may the actual higher yield strength be used for the design instead of the SMYS?"
In response to this question, your attention is called to §192.149, Standard fittings, paragraph (b), which states in part, "Each steel butt-welding fitting must have pressure and temperature ratings based on stresses for pipe of the same or equivalent material."
Section 195.118, Fittings, paragraph (c), states "The fitting must be suitable for the intended service and be at least as strong as the pipe and fittings in the pipeline systems to which it is attached."
The intent of these sections is that fitting strength be no lower than the strength of pipe of the same or equivalent material. In both §192.105, Design formula for steel pipe, and §192.106. Internal design pressure, it is required that the pipe design pressure be based upon the specified minimum yield strength. Thus, the specified minimum yield strength would be required to be used as the basis for determining the design pressure for weld fittings and not the actual measured yield strength.
Associate Director for
Pipeline Safety Regulation
Materials Transportation Bureau
Director, Office of Pipeline Safety Operations
|§ 192.105||Design formula for steel pipe|