HUNTSVILLE GAS SYSTEM

Incident Narrative

AT APPROXIMATLEY 2218 (10:18PM CST) ON JANUARY 15, 2013, HUNTSVILLE UTILITIES (HU) DISPATCH CENTER RECEIVED A TELEPHONE CALL FROM HUNTVILLE FIRE DEPARTMENT (HPD) REQUESTING EMERGENCY RESPONSE FROM THE HU GAS DEPARTMENT AT 850 WASHINGTON WHERE A STRUCTURE FIRE WAS IN PROGRESS. HFD DISPATCHER ADVISED THAT THEY RECEIVED A REPORT OF A ""BOOM"" FOLLOWED BY FIRE. GAS WAS SMELLED IN THE AREA AND OUR CREWS WERE URGENTLY REQUESTED. OPERATOR EMERGENCY RESPONDERS FROM HU GAS DEPARTMENT ARRIVED ON SITE AT 2230 (10:30PM CST) ON JANUARY 15, 2013. HFD AND THE HUNTSVILLE POLICE DEPARTMENT (HPD) WERE ON SITE AND HAD EXTINGUISHED A FIRE AT THE PUBLIC HOUSING DWELLING UNIT AT 851 UNIT C WASHINGTON ST AND SECURED THE AREA. UPON SMELLING NATURAL GAS THE EMERGENCY RESPONDERS CALLED FOR ADDITIONAL HELP TO LOCATE THE SOURCE OF THE APPARENT GAS LEAK. CREWS WERE CALLED IN AND WERE SUCCESSFUL IN SHUTTING OFF THE SUPPLY OF GAS TO THE ENTIRE PUBLIC HOUSING PROJECT AT 0230 (2:30AM CST) ON JANUARY 16, 2013. IT WAS DISCOVERED THAT AN UNDERGROUND STEEL DISTRIBUTION VALVE, 2 INCH IN DIAMETER, HAD A CRACKED FLANGE. THIS LEAK WAS REPAIRED BY REMOVING THE VALVE ALONG WITH ANOTHER SIMILIAR VALVE AND REPLACING IT WITH COATED STEEL PIPE. THE LEAK WAS TWENTY FEET AWAY FROM THE DWELLING AT 851 WASHINGTON ST. GAS SERVICE WAS THEN RESTORED TO THE AREA AT 0745 (7:45AM CST) ON JANUARY 16, 2013. AFTER THE LEAK WAS REPAIRED HU GAS DEPARTMENT CREWS BEGAN TO CONDUCT A NUMBER OF TESTS IN THE VICINTY OF 851 WASHINGTON ST. THESE TESTS INCLUDED A LEAK SURVEY, CATHODIC PROTECTION PIPE TO SOIL READINGS, BAR HOLE TEST AND A PRESSURE TEST OF ALL THREE GAS SERVICE LINES TO 851 WASHINGTON ST., AS THIS BUILDING WAS A TRI-PLEX COMPRISED OF UNITS A, B, AND C. ALL THREE GAS SERVICES HELD THE TEST PRESSURE OF APPROXIMATLY +125 PSIG WITH NO LEAKS INDICATED. A TEST OF THE FUEL LINE (CUSTOMER PIPING) AT UNIT C FAILED, INDICATING A LEAK INSIDE THE UNIT. AN INVESTIGATION INTO THE CAUSE OF THE INCIDENT IS ON GOING. CONTRIBUTING FACTOR(S) MAY HAVE BEEN THE LEAK ON THE FUEL LINE, THE UNDERGROUND GAS LEAK OR SOME OTHER FACTOR. THE LOCAL WEATHER CONDITIONS AT THE TIME OF THE INCIDENT WERE A TEMPERATURE OF 37 DEGREES FARENHEIT, THE WIND SPEED WAS 5 MPH, NO WIND GUSTS, WIND DIRECTION WAS 300 (GENERALLY OUT OF THE NORTHWEST). IT WAS OVERCAST WITH A LIGHT RAINFALL. A SUPPLEMENTAL OR SUPPLEMENTAL PLUS FINAL REPORT WILL BE FILED AS SOON AS NEW, UPDATED AND/OR CORRECTED INFORMATION IS KNOWN. SEPTEMBER 8, 2016-THIS IS A SUPPLEMENTAL REPORT RELATED TO THIS INCIDENT. EXPERT WITNESSES DETERMINED THAT SOMETHING HEAVY LIKE A VEHICLE RAN OVER A VALVE BOX CAUSING DOWNWARD PRESSURE ON A 2 INCH FLANGED ROCKWELL FIGURE 143 VALVE CAUSING THE VALVE TO CRACK IN A FLANGE. GAS THEN MIGRATED ALONG A DITCH LINE INTO THE DWELLING CAUSING AN EXPLOSION AND FIRE.