BALTIMORE GAS AND ELECTRIC COMPANY

Incident Narrative

AT APPROXIMATELY 11:00 AM ON 11/20/2023, DURING A ROUTINE INSPECTION OF A DISTRICT REGULATOR STATION LOCATED AT 1410 COVENTRY-MEADOWS DRIVE IN SYKESVILLE, MD, AN ABNORMAL OPERATING CONDITION OF OVER PRESSURIZATION WAS DISCOVERED ON THE GAS SYSTEM. DURING THE INSPECTION OF THE REGULATOR, A CONTROL LINE VALVE DIDN'T CLOSE PROPERLY DUE TO A BROKEN OPERATING HANDLE. THIS ALLOWED HIGHER PRESSURE GAS (250PSIG) TO FLOW INTO A MAIN WITH AN MAOP OF 99PSIG. THE CREW RECOGNIZED THE PROBLEM, AND THEIR INITIAL REACTIONS OF CLOSING/READJUSTING THE STATION BYPASS THROTTLE VALVE AND RELIEVING THE PRESSURE FROM THE REGULATOR STATION LIKELY CAUSED THE OHP PRESSURE TO ENTER THE DOWNSTREAM SIDE OF THE MAIN THROUGH THE BYPASS AND OVER PRESSURIZE THE MAIN. THE EVENT LASTED LESS THAN 15MIN BEFORE THE CREW WAS ABLE TO STABILIZE PRESSURE IN THE MAIN. A LEAK SURVEY OF THE IMPACTED AREA WAS PERFORMED, AND CREWS CHECKED ALL HOUSES IN THE AREA TO VERIFY PRESSURE AND TURN SERVICES OFF FOR SAFETY. 15 SERVICES WERE IMPACTED IN TOTAL, AND ALL WERE TURNED ON LATER THAT DAY AFTER INSPECTIONS WERE PERFORMED.