ENABLE GAS TRANSMISSION, LLC

Incident Narrative

ON 3/28/2016 AT 20:16 CENTERPOINT ENERGY-ARKLA NOTIFIED EGT OF A POSSIBLE GAS LEAK IN A CREEK WITHIN THE CITY LIMITS OF RUSSELLVILLE AR. AT 21:02, ENABLE GAS TRANSMISSION FIELD PERSONNEL CONFIRMED A LEAK ON EGT'S LINE B IN RUSSELLVILLE IN A CREEK CROSSING. THE PIPE WAS SUBMERGED IN 3 TO 5 FEET OF WATER. THE NEAREST STREETS ARE ASHBROOK DRIVE ON ONE SIDE AND E. 22ND ON THE OTHER. THE LEAK SITE WAS NOT WITHIN 220 YARDS OF ANY BUILDING INTENDED FOR HUMAN OCCUPANCY OR OUTDOOR PLACE OF ASSEMBLY. THE PRESSURE ON THE LINE (LINE B) WAS 464 PSIG, AND FIELD PERSONNEL COORDINATED WITH ENABLE SYSTEM CONTROL TO PLAN TO REDUCE THE PRESSURE TO 340 PSIG. THE LEAK WAS MONITORED OVERNIGHT. ON 3/29/2016 WE WERE ABLE TO INSTALL A 10X18 PLIDCO BOLT ON SLEEVE AND SLOWED THE LEAK DOWN TO A TRICKLE THAT WOULD ALLOW US TO SAFELY MONITOR IT UNTIL WE DEVELOPED A PROJECT TO REPLACE THE PIPE IN THE CREEK CROSSING. UNTIL A PERMANENT REPAIR COULD BE MADE A MANUAL BLOCK VALVE AT 2790+72 IS CLOSED AND ONE AT 3950+38 CLOSED TO ISOLATE 115,966 FEET AT LOWER PRESSURE AND FEEDING THIS SECTION FROM LINE BM-20 300 PSIG) TO KEEP THE CITY OF RUSSELLVILLE AND TOWNS WEST OF THERE IN SERVICE. THE LEAK SITE WAS MONITORED DAILY AND MATERIAL WAS ORDERED IN EARLY APRIL FOR THE REPAIR. WORK AND WELDING BEGAN ON JUNE 27TH, 2016. THE REPLACEMENT SECTIONS WAS HYDROSTATIC TESTED AND INSTALLED WITH WORK COMPLETE ON JULY 14TH, 2016. THE REPLACEMENT SECTION WAS 150 FEET IN LENGTH. THE REMOVED SECTION AND THE EXISTING SECTIONS WERE EXAMINED FOR INTERNAL CORROSION, WITH NONE FOUND. THE REMOVED SECTION WAS BROUGHT TO THE RUSSELLVILLE OPERATIONS WAREHOUSE WHERE THE PLIDCO SLEEVE WAS REMOVED FOR BETTER EXAMINATION OF THE LEAK AREA. THE EXTERNAL PIPE EXAMINATIONS SHOW EXTENSIVE ATMOSPHERIC CORROSION OF THE TOP PORTION OF THE LINE B CROSSING PIPE FOR APPROXIMATELY 11 FEET. THE LEAK AREA WAS AT THE 10 O'CLOCK POSITION FACING UPSTREAM IN THE CREEK.