Interpretation Response #PI-14-0013 ([Michigan Public Service Commission] [Mr. David J. Chislea])
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Michigan Public Service Commission
Individual Name: Mr. David J. Chislea
Location State: MI Country: US
View the Interpretation Document
Response text:
Mr. David J. Chislea
Manager of Gas Operations
Michigan Public Service Commission
6545 Mercantile Way
Lansing, Michigan 48909
Dear Mr. Chislea:
By letter to the Pipeline and Hazardous Materials Safety Administration (PHMSA) dated March 6, 2012, you requested an interpretation of certain pipeline welding requirements in 49 CFR Part 192. You stated that the Michigan Public Service Commission (MPSC) staff has identified instances where natural gas pipeline personnel performing welding operations utilize what is known as a "hinge" or "alignment" tack. You defined hinge or alignment tack as the deposition of filler metal at only one portion of a joint to aid in the lineup of the opposite side. By this process, a welder places filler metal at one location around the pipe joint and then the pipe is manipulated with heavy equipment to achieve better joint alignment elsewhere. The hinge or alignment tack can remain as part of the final weld.
You provided a summary of an operator's procedure as follows:
If constraints prevent the pipe segments from being adequately lined up, alignment tacks can be used if approved by the foreman. If approval is granted, an alignment tack less than 3" can be made and then the pipe can be shifted to attain the appropriate root opening for the remaining circumference. The root bead is then deposited, cleaned up, and the lineup clamps removed. At this point, the alignment tack is inspected for imperfections and if none exist the alignment tack can be left in as the root bead.
You stated that the MSPC believes the practice of applying a hinge or alignment tack and then moving the pipe to obtain better joint alignment is not acceptable per 49 CFR 192.235. Specifically, you request PHMSA's response to the following questions:
1. Whether placing a hinge or alignment tack and then moving the pipe to obtain better alignment elsewhere in the joint is an acceptable construction practice?
2. Whether the inclusion of a hinge or alignment tack into a finished weld which joint movement has taken place is a violation of § 192.235?
3. Whether hinge or alignment tacks are acceptable practices for establishing pipe alignment provided they are removed after the lineup clamp has been placed and adequate root bead has been deposited?
In order to respond to your questions, we reviewed § 192.235 which states:
§ 192.235 Preparation for Welding
Before beginning any welding, the welding surfaces must be clean and free of any material that may be detrimental to the weld, and the pipe or component must be aligned to provide the most favorable condition for depositing the root bead. This alignment must be preserved while the root bead is being deposited.
Our responses to your questions are as follows:
Response to question 1 – No, placing a hinge or alignment tack and then moving the pipe to obtain a better alignment elsewhere in the joint cannot meet the § 192.235 requirements because the alignment must be preserved while the root bead is being deposited.
Response to question 2 – Yes, the inclusion of a hinge or alignment tack into a finished weld which joint movement has taken place is a violation of § 192.235 because the alignment tack is compromised by the movement.
Response to question 3 – No, per responses 1 and 2 alignment tacks are not acceptable practices for establishing pipe alignment even if they are removed after the lineup clamp has been placed and adequate root bead has been deposited.
If we can be of further assistance, please contact Tewabe Asebe of my staff at (202) 366-5523.
Sincerely,
John A. Gale
Director, Office of Standards and Rulemaking