CONSOLIDATED EDISON CO OF NEW YORK

Incident Narrative

ON JANUARY 23, 2012 BRONX GAS OPERATIONS-CAPITAL CONSTRUCTION REPORTED TO THE GAS EMERGENCY RESPONSE CENTER (GERC) A SUSPECTED, UNCONFIRMED TRANSMISSION MAIN LEAK ON THE 24"" MAIN NEAR TRANSMISSION DRIP #24020 AT HOLLAND AVE. AND ARNOW AVE. AS PART OF AN ONGOING INVESTIGATION OF A LEAK ORIGINALLY SUSPECTED TO BE ON A 6""LOW PRESSURE CAST IRON MAIN IN THE VICINITY OF THE DRIP. DURING CONTINGENCY PREPARATION, A SECOND SUSPECTED, UNCONFIRMED LEAK WAS IDENTIFIED AT 24"" DRIP 24021 AT ADEE AVE. AND WALLACE AVE. AN OPERATIONAL PLAN WAS DEVELOPED INVOLVING THE INSTALLATION OF A 24"" CONTROL FITTING NORTH OF THE SUSPECTED LEAK AT DRIP 24021 AND THE USE OF AN EXISTING STRADDLE CONNECTION AT REGULATOR STATION GR-126 IN CONJUNCTION WITH V-6405 TO THE SOUTH IN ORDER TO MAINTAIN SUPPLY TO REGULATOR STATIONS GR-126, GR-110 AND GR-192. A WELDED 24"" CONTROL FITTING WAS INSTALLED AND WITH V-6405 CLOSED, THE AFFECTED SECTION OF MAIN WAS ISOLATED ON 1-30-12 AT 09:48 HRS, AND THE MAIN WAS REDUCED TO LOW PRESSURE. A NEW 24"" WELDED TRANSMISSION VALVE (#57434) WAS INSTALLED AND CLOSED, AND THE STOPPER WAS REMOVED RETURNING THE MAIN TO TRANSMISSION PRESSURE UP TO THE NEWLY INSTALLED CLOSED VALVE. DRIPS 24021 AND 24020 WERE EXCAVATED, CUT OUT AND REPLACED WITH NEW 24"" MAIN. A COUPLING APPROXIMATELY 50' NORTH OF DRIP 24020 WAS EXPOSED AND A WELDED REPAIR SLEEVE INSTALLED AS A PREVENTIVE MEASURE. LEAK SURVEY PERFORMED A SURVEILLANCE OF THE AFFECTED SECTION PRIOR TO RETURNING THE MAIN TO TRANSMISSION PRESSURE AND NO LEAKS WERE FOUND. THE MAIN WAS RETURNED TO NORMAL OPERATING PRESSURE ON FEBRUARY 3, 2012 AT 13:37 HRS. THERE WERE NO INJURIES OR EVACUATIONS. THE US DOT, NYS PSC AND NYC DEP WERE NOTIFIED. THIS WAS A SERIOUS LEVEL INCIDENT.