NATURAL GAS PIPELINE CO OF AMERICA (KMI)

Incident Narrative

NRC REPORT #1267113 AND NRC 48-HOUR UPDATE REPORT #1267191: 23:49-HOUR, 12/22/2019, RESIDENTS LIVING NEAR NGPL STATION 109 CALLED NGPL GAS CONTROL REPORTING A LOUD NOISE. 23:56-HOUR, 12/22/2019, NGPL GAS CONTROL STAFF CONTACTED NGPL ON-CALL STAFF. 00:38-HOUR, 12/23/2019, NGPL STAFF ARRIVED AT STATION 109, SAFELY ENTERED THE AREA AND FOUND NATURAL GAS RELEASING TO ATMOSPHERE FROM THE 8-INCH VENT VALVE ASSOCIATED WITH UNIT #14 THEREBY CONFIRMING THE INCIDENT. NGPL STAFF IMMEDIATELY CLOSED TWO MANIFOLD VALVES SERVING UNIT #14 TO TERMINATE THE NATURAL GAS RELEASE. 01:30-HOUR NGPL STAFF SPECIALIST ARRIVED ON SITE TO BEGIN INVESTIGATION OF THE INCIDENT AND BEGIN SUBSEQUENT REPAIRS AS NEEDED. INVESTIGATION OF THE INCIDENT FOUND THE UNIT #14 PLC ELECTRONIC CARD CONTROLLING SIGNAL OUT DISTRIBUTION HAD FAILED. WHEN THE PLC ELECTRONIC CARD SIGNAL OUT WAS NO LONGER AVAILABLE; THERE WAS NO SIGNAL COMMANDING THE VENT VALVE TO REMAIN IN THE CLOSED POSITION THEREFORE THIS VALVE OPENED AND RELEASED NATURAL GAS. BY DESIGN, WITH NO SIGNAL RECEIVED FROM THE PCL ELECTRONIC SIGNAL OUT DISTRIBUTION CARD, UNIT #14 CEASED RUNNING. HOWEVER THE MANIFOLD VALVES REMAINED OPEN IN THEIR RESPECTIVE POSITION AS LAST COMMANDED BY THE PLC. WITH FAILURE OF THE PLC ELECTRONIC SIGNAL OUT DISTRIBUTION CARD, THE PLC WAS UNABLE TO COMMAND THE MANIFOLD VALVES TO PROPER CLOSED POSITION WHICH WOULD HAVE RETAINED THE UNIT BLOW DOWN TO A TYPICAL NON-REPORTABLE VOLUME. 2:45-HOUR, NECESSARY REPAIRS WERE COMPLETED WHICH INCLUDED REPLACING THE PLC ELECTRONIC SIGNAL OUT DISTRIBUTION CARD AND FOLLOWING GENERAL INTEGRITY INSPECTION, UNIT #14 WAS AVAILABLE FOR SERVICE.