MIDDLE TENNESSEE NATURAL GAS UTIL DIST

Incident Narrative

ON JANUARY 8, 2018, FIRE CONSUMED A PERSONAL RESIDENCE LOCATED AT 266 ROMA DRIVE, CROSSVILLE, TENNESSEE. AN EXPLOSION WAS REPORTED IN CONJUNCTION WITH THE FIRE. THERE WERE THREE (3) OCCUPANTS IN THE HOME AT THE TIME OF THE INCIDENT. ONE OCCUPANT RECEIVED INJURIES REQUIRING HOSPITALIZATION. AT APPROXIMATELY 8:34 P.M. (CST), MIDDLE TENNESSEE NATURAL GAS UTILITY DISTRICT (MTNGUD) RECEIVED A REPORT OF A FIRE AND EXPLOSION AT 266 ROMA DRIVE, CROSSVILLE, TENNESSEE. AT APPROXIMATELY 8:40 P.M. (CST) TWO MTNGUD SERVICE TECHNICIANS ARRIVED AT THE SCENE. THE FIRE DEPARTMENT AND OTHER EMERGENCY SERVICE PROVIDERS WERE ON THE SCENE. THE HOUSE WAS IN FLAMES. AT APPROXIMATELY AT 8:45 P.M. (CST), THE SERVICE TECHNICIANS CUT AND CAPPED THE THREE-QUARTER INCH (3/4"") P.E. SERVICE LINE APPROXIMATELY THIRTY (30) FEET FROM THE HOUSE. A REMOTE METHANE LEAK DETECTION SURVEY WAS PERFORMED TO DETERMINE THE PRESENCE OF NATURAL GAS. THE SURVEY DETECTED A SLIGHT READING WHICH DISSIPATED FOLLOWING THE CAPPING OF THE SERVICE LINE. BEFORE THE SERVICE TECHNICIANS LEFT THE SCENE THEY REMOVED THE GAS METER AND REGULATOR WHICH WERE DAMAGED BEYOND USE IN THIS INCIDENT. MTNGUD TECHNICIANS DID NOT INVESTIGATE ANY PIPE DOWNSTREAM OF THE GAS METER. ON JANUARY 9, 2018, MTNGUD PERSONNEL CONDUCTED AN ODORANT TEST NEAR THE INCIDENT SITE. THE ODORANT WAS IN AN ACCEPTABLE RANGE. ON JANUARY 11, 2018, AN AIR TEST ON THE SERVICE LINE INDICATED A FAILURE OF THE SERVICE LINE. EXCAVATION UNDER A CONCRETE SLAB LED TO DISCOVERY OF A SERVICE LINE REPAIR BY USE OF A COMPRESSION COUPLING. THIS REPAIR LOCATION WAS DIRECTLY UNDERNEATH A FOUR-INCH PVC DRAIN PIPE. ONE END OF THE SERVICE LINE WAS DISCONNECTED FROM THE COUPLING. IT IS UNKNOWN IF THIS DISCONNECTION OCCURRED BEFORE OR DURING THE EXPLOSION. FURTHER INVESTIGATION REVEALED TWO (2) ADDITIONAL DAMAGED AREAS ON THE SERVICE LINE. IN 2006, AN EXCAVATOR HIT AND CUT THE LINE. THIS DAMAGE HAD BEEN REPAIRED BY USE OF A STAB FITTING. THIS REPAIR WAS INTACT. THE SIGHT OF A CROSSING OF THE SERVICE LINE WITH A CABLE TV LINE REVEALED THAT THE SERVICE LINE HAD BEEN STRUCK AND PULLED WITH FORCE LEAVING MARKS AND DISTORTION ON THE LINE. THE LINE REMAINED SERVICEABLE AT THIS DAMAGE LOCATION. AN MTNGUD SERVICE TECHNICIAN WAS ONSITE AT THIS METER ON 12/5/17 FOR A REGULAR ANNUAL PRESSURE CONFIRMATION AND THERE WERE NO INDICATIONS OF IRREGULARITIES OR ABNORMAL OPERATING CONDITIONS AT THAT TIME. WEATHER IN CROSSVILLE, TENNESSEE, PRIOR TO THIS INCIDENT WAS UNUSUALLY COLD WITH FREEZING AND THAWING OF THE GROUND IN THE VICINITY, WHICH MAY HAVE CONTRIBUTED TO THE COUPLING TO SERVICE LINE FAILURE. PREVIOUS EXCAVATION DAMAGE MAY ALSO HAVE COMPROMISED THE INTEGRITY OF THIS CONNECTION. THE SEPARATION OF THE COUPLING FROM THE SERVICE LINE WAS SO COMPLETE, IT RAISES ISSUES OF THE TIME AND CAUSE OF THE SEPARATION.