PHILADELPHIA GAS WORKS

Incident Narrative

ON THURSDAY, JANUARY 30, 2014 AT 17:21, PGW RECEIVED AN INSIDE LEAK CALL FROM A CUSTOMER THROUGH PGW'S CALL CENTER WITH A HEADING OF 1845 S. BANCROFT STREET. AN FSD TECHNICIAN WAS DISPATCHED TO INVESTIGATE THIS LEAK. HE ARRIVED ON LOCATION AT 17:29 AND BEGAN HIS INVESTIGATION. A READING OF 70% LEL AT THE FRONT FOUNDATION WALL TO 1845 S. BANCROFT WAS REPORTED BY THE TECHNICIAN TO THE FSD DISPATCHER. BASED ON THIS REPORT, A DISTRIBUTION CREW WAS DISPATCHED AT 18:10. FSD AND DISTRIBUTION SUPERVISION WERE ALSO DISPATCHED TO THE LOCATION. THE CREW ARRIVED ON LOCATION AT 18:24 AND IMMEDIATELY BEGAN THEIR INVESTIGATION. DURING THE COURSE OF THE INVESTIGATION AND WHILE THE DISTRIBUTION FOREMAN AND THE FSD TECHNICIAN WERE INSIDE THE PROPERTY AT 1849 S. BANCROFT CHECKING FOR GAS READINGS, AN EXPLOSION TOOK PLACE AT APPROXIMATELY 19:05 INSIDE 1849 S. BANCROFT. THE EXPLOSION SEVERELY DAMAGED THE TWO RESIDENTIAL BUILDINGS AT 1849 AND 1847 S. BANCROFT. IT ALSO INJURED BOTH PGW EMPLOYEES WHO WERE INSIDE THE HOUSE, AS WELL AS ONE HOMEOWNER. THE INJURIES SUSTAINED BY ALL THREE INDIVIDUALS WERE NON-LIFE THREATENING. BOTH THE DISTRIBUTION FOREMAN AND HOMEOWNER WERE TAKEN TO A LOCAL HOSPITAL FOR TREATMENT AND RELEASED ON THE SAME DAY WHILE THE FSD TECHNICIAN WAS ADMITTED WITH BURNS TO HIS NECK AND LOWER TORSO. THE EXPLOSION AT THE SCENE WAS OBSERVED BY A FSD SUPERVISOR WHO HAD JUST ARRIVED ON THE SCENE AT 19:05. PHILADELPHIA FIRE DEPARTMENT, PHILADELPHIA POLICE DEPARTMENT AND PECO ENERGY WERE CALLED IN FOR ASSISTANCE, IN ADDITION TO VARIOUS PGW RESOURCES SUCH AS, DISTRIBUTION CREWS, FSD TECHNICIANS, MOBILE EQUIPMENT, GREASE TRUCK, SUPERVISORY PERSONNEL, CHEMICAL SERVICES, ETC. THE PAPUC WAS ALSO NOTIFIED OF THE INCIDENT. THE GAS MAIN IN THE EAST FOOTWAY IN FRONT OF 1849 S. BANCROFT (4"" 1939 LOW PRESSURE CAST IRON MAIN) WAS GREASED OFF THROUGH A PLASTIC SERVICE TO 1843 S. BANCROFT AT 19:51 AND THE LEAK CONSEQUENTLY WAS MADE SAFE. AS A RESULT OF THE GREASING OFF, A TOTAL OF FOUR (4) PROPERTIES WERE TEMPORARILY OUT OF GAS. PECO ALSO SHUT OFF THE ELECTRIC POWER TO 1849 S. BANCROFT AT 21:00. AFTER MAKING THE JOB SAFE AND RECEIVING THE GO AHEAD FROM PFD, PGW PERSONNEL ON THE SCENE CONTINUED WITH THE INVESTIGATION. EVERY BUILDING ON THE 1800 BLOCK OF S. BANCROFT WAS CHECKED FOR GAS READINGS. ALSO, THE 4"" CAST IRON MAIN ON THE BLOCK ALONG WITH ALL ACTIVE GAS SERVICES WERE BAR HOLED IN ORDER TO CHECK FOR ANY POSSIBLE LEAKS. DURING THIS BLOCK CHECK THE CREW PICKED UP LEL READINGS IN FRONT OF 1835 AND 1816/1818. A BROKEN MAIN WAS EVENTUALLY FOUND AND REPAIRED IN FRONT OF 1818 AND A TOTAL OF SIX (6) SERVICES ON THE BLOCK WERE RENEWED WITH PLASTIC. THE GREASED 4"" MAIN WAS ALSO CUT AND CAPPED AT 03:45. THIS PORTION OF THE 4"" MAIN THAT WAS CUT AND CAPPED (100') WAS AIR TESTED AT 6"" WC AND THE TEST FAILED. THIS SECTION OF THE MAIN WAS THEN EXCAVATED COMPLETELY AND A BROKEN MAIN WAS FOUND IN FRONT OF 1849. AN 8' SECTION OF THE PIPE, CONTAINING THE BROKEN MAIN, WAS CUT AND REMOVED FROM THE EXCAVATION, TAGGED AS EVIDENCE AND TRANSPORTED TO THE PGW EVIDENCE ROOM ON 1/31/2014. IT IS BELIEVED FROST HEAVE WAS THE CAUSE OF THE BROKEN MAIN, FOURTEEN INCHES OF FROST WAS MEASURED AT THIS LOCATION. THE SERVICES TO 1845 AND 1847 (BOTH 1 1/4"" UNPROTECTED STEEL SERVICES) WERE ALSO AIR TESTED AND FAILED. AFTER THE INVESTIGATION WAS COMPLETED, THE GAS SERVICE WAS RESTORED TO THE PROPERTIES THAT WERE SHUT OFF DURING THE GREASE OFF PROCESS. THE BUILDING AT 1849 WAS DEMOLISHED ON 2/1/2014. PGW SUBSEQUENTLY REPLACED THE 4"" CAST IRON MAIN. ANALYSIS OF THE INCIDENT PIPE SHOWED THAT IT NEVER COMPLETELY FRACTURED CIRCUMFERENTIALLY AND THE CRACK WAS CONSIDERED TIGHT WITH NO LARGE GAP BETWEEN THE MATING SURFACES. THE CAST IRON MAIN EXHIBITED GRAPHITIZATION BUT THE INTEGRITY OF THE PIPE WOULD HAVE PERSISTED IF LEFT UNDISTURBED AND NOT UNDER LOADING CONDITIONS. THE LOADING CONDITIONS ARE BELIEVED TO BE CAUSED BY THE EFFECTS OF 14 INCHES OF FROST.