NTSB Safety Recommendation P-76-052

NTSB safety recommendation P-76-052.

DEVELOP A PROCEDURE TO SHUT DOWN THE SYSTEM DURING EMERGENCIES. AS PART OF THIS PROCEDURE, DEVELOP DISTRIBUTION SYSTEM MAPS SHOWING VALVE LOCATIONS, DETERMINE OPTIMUM SPACING OF HIGH-PRESSURE VALVES IN EACH OF THE NNG DISTRIBUTION SYSTEMS, AND INSTALL ADDITIONAL VALVES, IF NECESSARY, TO REDUCE THE TIME REQUIRED TO SHUT DOWN A SECTION OF MAIN IN AN EMERGENCY.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 1976-09-15

Adopted Date: 1976-07-07

Overall Date Closed: 1980-08-12

Synopsis: ON JANUARY 10, 1976, GAS WHICH WAS LEAKING INTO THE PATHFINDER HOTEL, IN FREMONT, NEBRASKA, IGNITED. THE GAS WAS LEAKING FROM A 2-INCH PLASTIC PIPE WHICH HAD PULLED OUT OF ITS COMPRESSION COUPLING; THE GAS SEEPED INTO THE HOTEL BECAUSE IT HAD BEEN CAPPED ABOVE BY FROZEN EARTH AND A CONCRETE ROAD SURFACE. THE HOTEL EXPLODED AND FIRE ENSUED; THE EXPLOSION AND FIRE DESTROYED THE HOTEL, DAMAGED NEARBY BUILDINGS, AND BROKE WINDOWS WITHIN A ONE-BLOCK RADIUS. THIRTY-NINE PERSONS WERE INJURED AND 20 PERSONS WERE KILLED.

Ntsbnumber: DCA76MP013

Report Number: PAR-76-06

Addressee Name: Nebraska Natural Gas Company

Addressee Status: Closed--No Longer Applicable

Addressee Date Closed: 1980-08-12

Addressee Organization Type: P-Private Industry

Communication Date: 1978-05-22

Communication Type: Official Correspondence

Communication Contents: NEBRASKA NATURAL GAS COMPANY LTR: WE PRESENTLY FOLLOW A POLICY THAT WAS ESTABLISHED WITHIN A FEW DAYS FOLLOWING THE ACCIDENT OF CONNECTING PLASTIC DISTRIBUTION MAINS AND SERVICES TO STEEL IN THE FOLLOWING MANNER. WE FUSE A TRANSITION (PLASTIC TO STEEL) FITTING TO THE PLASTIC PIPE. WE THEN WELD THE STEEL TO STEEL OR CONNECT THE STEEL TO STEEL WITH A COMPRESSION COUPLING. IF A COMPRESSION COUPLING IS USED, WE, IN ALL APPLICATIONS, SPOT WELD, ELECTRICALLY, A 3/4" STEEL STRAP FROM THE EXISTING STEEL MAIN TO THE STEEL PORTION OF THE TRANSITION FITTING, THUS PROVIDING A POSITIVE ANCHOR TO ELIMINATE EVERY LIKELIHOOD OF A JOINT SEPARATION. THE JOINT IS CATHODICALLY BONDED AND WRAPPED TO INSURE ITS LONGEVITY. WE HAVE CHECKED 99 PERCENT OF THE CONNECTIONS IN OUR SYSTEM COMPANY-WIDE ON PIPE SIZES ABOVE 1" TO INSURE THAT NO FURTHER PULLOUTS OCCUR. 6/19/80 - NEBRASKA NATURAL GAS COMPANY LTR: A REVIEW OF VALVE LOCATION AND FREQUENCY HAS BEEN MADE BY THE COMPANY. IN THE FREMONT CITY DISTRIBUTION SYSTEM, THE ENTIRE DOWNTOWN RETAIL AND COMMERICAL SERVICE AREA HAS BEEN ISOLATED BY VALVES IN HIGH PRESSURE DISTRIBUTION PIPING. THE AREA HAS BEEN DIVIDED INTO FOUR ZONES AND A DETAILED MAP HAS BEEN DRAWN TO SHOW LOCATION OF VALVES RELATING TO EACH SECTION. THE FREMONT OPERATING PERSONNEL HAVE ALL BEEN ORIENTED ON VALVE LOCATION AND ARE ANNUALLY RE-ORIENTED AS TO LOCATION AND PROCEDURE. MAPS ARE CARRIED BY ALL KEY PERSONNEL. AS TO OTHER AREAS OF THE CITY, ALL NEW SUB-DIVISIONS ARE VALVED TO ISOLATE EACH DIVISION FOR EMERGENCY PURPOSES. EVALUATION OF EACH AREA HAS BEEN MADE TO DETERMINE ISOLATION FOR EMERGENCY PURPOSES. DISTRICT REGULATOR AND/OR BORDER STATION DELIVERY POINTS ARE DETERMINED TO BE ADEQUATE TO ISOLATE AREAS IN ALL TOWNS SERVED.

Addressee Organization Type: P-Private Industry

Communication Date: 1980-08-12

Communication Type: Official Correspondence