DOMINION EAST OHIO — Gas transmission and gathering — incident on 2015-03-25

Gas transmission and gathering incident in NEW PHILADELPHIA, TUSCARAWAS County, OH. Reported cause: MATERIAL FAILURE OF PIPE OR WELD. Reported consequences: 0 fatalities, 0 injuries, 774 released, $51,800 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20150057.

Operator ID: 4060.

Reported incident date: 3/25/2015 9:30.

Location detail: 2110+40

Cause detail: DESIGN-, CONSTRUCTION-, INSTALLATION-, OR FABRICATION-RELATED

Cause detail: ON MARCH 25, 2015 AT APPROXIMATELY 9:30 A.M., WHILE WORKING TO REPAIR A GRADE 2 LEAK A CRACK ON A DOMINION FACILITY NEAR THE PAD SADDLE AROUND THE TAP WAS DISCOVERED. ON MARCH 26, 2015, THE SECTION OF PIPE WAS CUT OUT AND REPLACED. PRESSURE WAS RESTORED AND THE LINE WAS PUT BACK INTO SERVICE ON MARCH 28, 2015 AT APPROXIMATELY 1:00 P.M. THE SECTION OF PIPE THAT LEAKED WAS SENT TO A 3RD PARTY LABORATORY FOR FAILURE ANALYSIS. THE RESULT OF THE 3RD PARTY ANALYSIS DETERMINED THAT THE FAILURE WAS CAUSED BY DUCTILE OVERLOAD OF THE PIPE WALL AT THE WELD TOE. THE PRIMARY FACTOR TO THE FAILURE WAS SETTLEMENT OF THE BRANCH CONNECTION DUE TO IMPROPER SUPPORT. THE SETTLEMENT CAUSED BENDING STRESSES IN THE CARRIER PIPE AT THE SADDLE REINFORCEMENT FILLET WELD WHICH RESULTED IN THE FORMATION OF A CRACK. THE GEOMETRY OF THE FILLET WELD THAT ATTACHED THE SADDLE REINFORCEMENT PAD TO THE CARRIER PIPE WAS ALSO A CONTRIBUTING FACTOR TO THE FAILURE. THE SADDLE THICKNESS WAS 2.5 TIMES THE THICKNESS OF THE CARRIER PIPE WHICH CONTRIBUTED TO A STRESS CONCENTRATION IN THE THINNER PIPE AT THE FILLET WELD TOE. UNDERCUT AT THE TOE OF THE FILLET WELD FURTHER CONCENTRATED THE STRESS AND CONTRIBUTED TO THE FORMATION OF A CRACK.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: MATERIAL FAILURE OF PIPE OR WELD — CONSTRUCTION, INSTALLATION OR FABRICATION-RELATED.

PHMSA indexed costs: $83,194 reported total cost, $52,967.986 in 1984 dollars, $100,223.124 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.