KEYSPAN ENERGY DELIVERY - NY CITY

Incident Narrative

INCIDENT OCCURRED BY IGNITION OF A CUSTOMER RANGE IN APARTMENT BUILDING AT 40 CLINTON STREET, BROOKLYN, NY. THE ROOT CAUSE WAS OVERPRESSURIZATION OF THE GAS SERVICE REGULATOR SUPPLYING COOKING LOADS TO 152 APARTMENTS, DUE TO IMPROPER INSTALLATION OF THE VENT LINES AT THE TIME OF THE INITIAL INSTALLATION. THIS WAS A PARALLEL GAS SERVICE REGULATOR INSTALLATION. PART OF THE VENT LINES WERE INSTALLED BELOW GRADE, PASSING THROUGH TWO CONCRETE BARRIERS: ONE AT FOUNDATION WALL, AND ONE AT SIDEWALK. THESE VENT LINES WERE BOTH UNSLEEVED, AND CORRODED OVER TIME. WATER FROM THE SURROUNDING SOIL INFILTRATED THE VENT LINE AND COLLECTED ON TOP OF THE PRIMARY REGULATOR DIAPHRAGM AND FROZE. IN ADDITION, THE VENT LINE WAS PARTIALLY FROZEN AND BLOCKED. THE SECONDARY REGULATOR SERVED TO VENT EXCESS GAS DUE TO ELEVATED PRESSURE. A SERVICE PERSON RESPONDING TO A CALL AT THIS LOCATION FOUND THE COUPLING ON THE SECONDARY VENT LINE DISCONNECTED, AND OUT OF AN ABUNDANCE OF CAUTION, ""VALVED OUT"" THE SECONDARY REGULATOR TO STOP THE FLOW OF BLOWING GAS. THIS PREVENTED THE INTERNAL RELIEF OF THE SECONDARY GAS SERVICE REGULATOR TO VENT THE EXCESS PRESSURE FROM THE FAILED REGULATOR; THEREFORE BOTH RELIEF VALVES WERE RENDERED INEFFECTIVE, ALLOWING DOWNSTREAM PRESSURE TO BUILD UP TO LEVELS BEYOND RECOMMENDED LIMITS FOR THE CUSTOMERS' EQUIPMENT AND A FIRE RESULTED IN ONE OF THE APARTMENTS. COOKING LOADS FOR ALL 152 APARTMENTS REMAIN TURNED OFF UNTIL THE ASSIGNED PLUMBER OBTAINS THE PERMIT FROM THE DEPARTMENT OF BUILDINGS. IN PART G ABOVE, THE TASK WHICH LED TO THE INCIDENT WAS NOT A COVERED TASK FOR OUR OQ PROGRAM AT THE TIME OF THE SERVICE AND EQUIPMENT INSTALLATION; HOWEVER, IT IS A COVERED TASK AT THIS POINT IN TIME. LAST SERVICE WAS RESTORED ON 9/1/2016