CONSOLIDATED EDISON CO OF NEW YORK

Incident Narrative

AT 06:02 ON MAY 29, 2013 PROCEDURE MPC 13-19 WAS INITIATED DUE TO THE INVESTIGATION OF LEAK (XL13001342) IN THE VICINITY OF THE TRANSMISSION SYSTEM AT THIS LOCATION. IN ADDITION TO THE 20"" TRANSMISSION MAIN (OPERATING AT LESS THAN 20% SMYS), LOCATED IN THIS VICINITY IS THE 12"" TRANSMISSION STRADDLE CONNECTIONS SUPPLYING TP-HP-MP GR-102, (3) TRANSMISSION VALVES AND ASSOCIATED FITTINGS AS WELL AS 12"" LOW PRESSURE POLYETHYLENE (LPPE) AND 12"" LOW PRESSURE CAST IRON DISTRIBUTION MAINS AND SERVICES. CONTINGENCY B13-044; CASE 20 & 21-A WAS PLACED IN EFFECT. AT 09:16 ISOLATION OF THE AFFECTED SEGMENT WAS ACHIEVED AND PRESSURE WAS REDUCED FROM 200 PSI TO 60 PSI PER THIS PROCEDURE AND EXCAVATION OPERATIONS BEGAN. THE (3) VALVES AT THIS LOCATION (20"" MAIN LINE V-7583 AND 12"" INLETS V-7584/7585) WERE INVESTIGATED FOR A POSSIBLE SOURCE OF THE SUSPECTED LEAK AND A VISIBLE LEAK ON THE BLEED CONNECTION TO THE VALVE BODY OF 12"" INLET V-7585. ADDITIONALLY, A VISIBLE LEAK ON A .5"" RELIEF VALVE BOTTOM OF THE BODY OF 20"" V-7583 WAS LOCATED UNDER THE GEAR BOX. THIS VALVE'S OUTER FLANGES WERE ABATED AND VISIBLE LEAKS WERE LOCATED ON BOLTS OF THE SOUTH FLANGE AT THE 6-8 O'CLOCK POSITION. ATTEMPTS TO REPAIR THE LEAKS WERE NOT SUCCESSFUL AND AN OPERATIONAL PLAN WAS IDENTIFIED FOR THE REPLACEMENT OF THE 20"" MAIN LINE VALVE, (2) 12"" INLET VALVES TO GR-102 AND ASSOCIATED PIPING. PRESSURE REDUCTION IN THE AFFECTED SEGMENT OF TRANSMISSION MAIN WAS ACHIEVED AND THE OPERATIONAL PLAN CONTINUED AROUND-THE-CLOCK. ON JUNE 9, 2013 INSTALLATION OF APPROXIMATELY 12' OF 20'' PIPE AND 8' OF 12"" PIPE ASSOCIATED WITH THE (3) REPLACEMENT VALVES WAS COMPLETED. ALL WELDING WAS TESTED AND PASSED SUCCESSULLY. LEAK SURVEY MONITORED THE ISOLATED SEGMENT OF MAIN AS PRESSURE WAS RESTORED INCREMENTALLY AND NO LEAKS WERE DETECTED. AT 14:53 NORMAL SYSTEM CONDITIONS RESUMED. THERE WAS NO MIGRATION BEYOND THE OPEN EXCAVATION; ALL SUBSURFACE STRUCTURES REMAINED GAS FREE DURING THIS OPERATION. THERE WERE NO REPORTED OUTAGES OR NEGATIVE SYSTEM IMPACT AS A RESULT OF THIS PROCEDURE. THERE WERE NO INJURIES, EVACUATIONS OR MEDIA ATTENTION REPORTED. THE US DOT, PSC, DEP WAS NOTIFIED AND THE FDNY WAS NOTIFIED UNDER THE TRANSMISSION LEAK NOTIFICATION PROTOCOL. THE SERIOUS LEVEL INCIDENT WAS TERMINATED.