NTSB Safety Recommendation P-91-018

NTSB safety recommendation P-91-018.

THE NTSB RECOMMENDS THAT THE CITY OF ALLENTOWN: COORDINATE WITH THE UGI CORPORATION TO OBTAIN INITIAL AND RECURRENT TRAINING FOR EMERGENCY RESPONSE PERSONNEL ON CONTROLLING NATURAL GAS IN EMERGENCY SITUATIONS, INCLUDING HOW TO LO CATE, IDENTIFY, AND OPERATE OUTSIDE KEY-OPERATED SHUTOFF VALVES.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 1991-08-06

Adopted Date: 1991-07-23

Overall Date Closed: 2001-04-30

Synopsis: ON 8/29/90, A NATURAL GAS EXPLOSION & FIRE DESTROYED TWO ROW HOUSES AT 421-423 NORTH FIFTH STREET & DAMAGED TWO ADJACENT HOUSES & THREE PARKED CARS IN ALLENTOWN, PA. ONE PERSON WAS KILLED, & NINE PEOPLE, INCLUDING TWO FIREFIGHTERS, WERE INJURED. THE NTSB'S INVESTIGATION DISCLOSED THAT WATER LEAKING FROM A CIRCUMFERENTIAL CRACK IN A 6-INCH CAST-IRON MUNICIPAL WATER MAIN BENEATH NORTH FIFTH STREET'S EAST SIDE HAD ERODED THE SOIL FOUNDATION OF A LOW PRESSURE (9 INCHES WATER COLUMN PRESSURE) 4-INCH CAST-IRON UGI CORPORATION (UGI) GAS MAIN BENEATH THE WEST SIDE OF NORTH FIFTH STREET. THE GAS MAIN SUBSEQUENTLY CRACKED CIRCUMFERENTIALLY AND NATURAL GAS FILLED THE VOID BENEATH THE PAVEMENT. NATURAL GAS THEN MIGRATED THROUGH THE SOIL & INTO THE BASEMENT OF 423 NORTH FIFTH STREET, WHERE IT IGNITED, EXPLODED, & BURNED. SUBSEQUENT METALLURGICAL EXAMINATIONS REVEALED THAT BOTH CAST-IRON MAINS WERE SIGNIFICANTLY WEAKENED BY GRAPHITIC CORROSION. THE WATER MAIN WAS INSTALLED IN THE LATE 1800S & THE GAS MAIN WAS INSTALLED IN 1903.

Probable Cause: Undermined and weakened segment of cast-iron gas main

Keywords: Firefighting, Training and Education

Ntsbnumber: DCA90FP011

Report Number: PAB-91-01

Addressee Name: Commonwealth of Pennsylvania, City of Allentown

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 2001-04-30

Addressee Organization Type: L-Local Government

Communication Date: 2001-04-30

Communication Type: Official Correspondence

Communication Contents: On March 12, 1997, based on information provided in the UGI Corporation's letter of November 20, 1996, Safety Recommendation P-91-13, to UGI Corporation was classified "Closed-Acceptable Action." Accordingly, because the City of Allentown participated with the UGI Corporation on this issue, Safety Recommendation P-91-18 to the City of Allentown is classified "Closed-Acceptable Action."