NTSB Safety Recommendation P-06-002

NTSB safety recommendation P-06-002.

The National Transportation Safety Board recommends that the National Fuel Gas Distribution Corporation: Revise your butt-fusion procedures for plastic pipe to include a requirement for determining drag force in the field for each butt-fusion joint.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 2006-06-08

Adopted Date: 2006-05-31

Overall Date Closed: 2006-12-14

Synopsis: On August 21, 2004, about 8:54 a.m., a natural gas explosion destroyed a residence located at 48 Woodland Lane in DuBois, Pennsylvania. Two residents were killed in this accident. The Safety Board determined that the probable cause of the leak, explosion, and fire in DuBois, Pennsylvania, on August 21, 2004, was the fracture of a defective butt-fusion joint and the failure of National Fuel to have an adequate program to inspect butt-fusion joints and replace those joints not meeting its inspection criteria.

Probable Cause: The National Transportation Safety Board determines that the probable cause of the leak, explosion, and fire in DuBois, Pennsylvania, on August 21, 2004, was the fracture of a defective butt-fusion joint and the failure of the National Fuel Gas Distribution Corporation to have an adequate program to inspect butt-fusion joints and replace those joints not meeting its inspection criteria.

Ntsbnumber: DCA04MP006

Report Number: PAB-06-01

Addressee Name: National Fuel Gas Distribution Corporation

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 2006-12-14

Addressee Organization Type: P-Private Industry

Communication Date: 2006-08-10

Communication Type: Official Correspondence

Communication Contents: Letter Mail Controlled 8/21/2006 2:42:19 PM MC# 2060406: As a preliminary note, NFGDC disagrees with the Safety Board’s determination contained in the Safety Recommendation that the probable case of the leak, explosion and fire . . . was the fracture of a defective butt-fusion joint and the failure of National Fuel to have an adequate program to inspect butt-fusion joints and replace those joints not meeting its inspection criteria. To the contrary, NFGDC maintains that the probable cause of the leak was a third party excavation that undermined and placed an undue bending stress on a butt-fusion joint causing a failure in the pipe adjacent to that butt-fusion joint. Further, NFGDC’s pipeline inspection program has met, and continues to meet, all applicable requirements. That disagreement notwithstanding, NFGDC has duly considered the Safety Recommendation and, consistent therewith, is implementing the changes discussed below to its procedures. Copies of the amended pages from our Operations and Maintenance Manual are enclosed as Attachments A & B. NFGDC considers these documents to contain proprietary information and request that they be treated as confidential pursuant to 49 CFR 831.6. NFGDC is revising its butt-fusion procedures to include the following language: When butt fusing longer lengths of pipe, additional pressure may be required during the heating and joining steps to compensate for the additional drag forces present. Add slack to pipe(s) if possible and use pipe support stands to minimize drag. Drag force must be determined on a case-by-case basis. Acceptable melt and fusion bead appearance will indicate adequate pressure. -See Attachment A. In addition, NFGDC is revising its procedures to indicate that drag force must be addressed differently depending on the type of fusion machine being used (e.g. hydraulic or manual). Id. Additional revisions to NFGDC’s butt-fusion procedure addressing drag force include: (1) requiring that pipe support stands be used with all fusion machines when conditions permit; (2) eliminating the use of butt fusions to join two sections of coiled pipe; and (3) prohibiting the use of butt fusions in the ditch when a buried section of main is to be joined to a newly installed section. -See Attachments A & B. If you should have any questions, comments or concerns regarding any aspect of the foregoing, please do not hesitate to contact me at (716) 857-7575. /s/ James D. Ramsdell

Addressee Organization Type: P-Private Industry

Communication Date: 2006-12-14

Communication Type: Official Correspondence

Communication Contents: The Safety Board notes that the NFGDC has revised its butt-fusion procedures to include the following language: When butt fusing longer lengths of pipe, additional pressure may be required during the heating and joining steps to compensate for the additional drag forces present. Add slack to pipe(s) if possible and use pipe support stands to minimize drag. Drag force must be determined on a case-by-case basis. Acceptable melt and fusion bead appearance will indicate adequate pressure. In addition, the NFGDC is revising its procedures to indicate that drag force must be addressed differently (either hydraulically or manually), depending on the type of fusion machine being used. Revisions have been made to the NFGDC’s butt-fusion procedure addressing drag force, to include the following: requiring that pipe support stands be used with all fusion machines when conditions permit eliminating the use of butt fusions to join two sections of coiled pipe prohibiting the use of butt fusions in the ditch when a buried section of main is to be joined to a newly installed section Because the NFGDC has revised these procedures as recommended, Safety Recommendation P-06-2 is classified Closed Acceptable Action.