NTSB Safety Recommendation P-91-014

NTSB safety recommendation P-91-014.

THE NTSB RECOMMENDS THAT THE UGI CORPORATION: IMPLEMENT A COMPREHENSIVE GAS SYSTEM SURVEILLANCE PROGRAM THAT: 1) IDENTIFIES THE TYPE OF DATA TO BE COLLECTED ON GAS SYSTEM FAILURES, GAS LEAKAGE SURVEYS, CHANGES IN CORROSION PRO TECTION LEVELS, & ABNORMAL OPERATING & MAINTENANCE CONDITIONS; 2) ESTABLISHES THE TYPE & FREQUENCY OF ANALYSES TO BE PERFORMED FOR IDENTIFYING POTENTIALLY UNSAFE CONDITIONS; AND 3) SPECIFIES THE CORRECTIVE ACTION TO BE TAKEN.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 1991-08-06

Adopted Date: 1991-07-23

Overall Date Closed: 1994-04-22

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

Ntsbnumber: DCA90FP011

Report Number: PAB-91-01

Addressee Name: UGI Corporation

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 1994-04-22

Addressee Organization Type: P-Private Industry

Communication Date: 1991-10-17

Communication Type: Official Correspondence

Communication Contents: P-91-14--UGI BELIEVES THAT THE VARIOUS COMPONENTS OF OUR CURRENT SURVEILLANCE PROGRAM DO MEET THE BOARD'S RECOMMENDATION.

Addressee Organization Type: P-Private Industry

Communication Date: 1992-10-07

Communication Type: Official Correspondence

Communication Contents: IN RESPONSE TO THE BOARD'S CONCERNS, UGI WILL CONSOLIDATE ITS EXISTING PROGRAMS INTO A SYSTEM SURVEILLANCE PLAN WHICH WILL BE A SINGLE DOCUMENT DESIGNED TO PROVIDE GUIDANCE AND EVALUATION CRITERIA TO AREA ENGINEERING AND FIELD PERSONNEL TO ASSURE EFFECTIVE AND CONSISTENT OF OUR DISTRIBUTION SYSTEM. THIS DOCUMENT WILL BE REFERENCED IN OUR MANUAL OF STANDARD PROCEDURES AS APPROPRIATE.

Addressee Organization Type: P-Private Industry

Communication Date: 1994-01-14

Communication Type: Official Correspondence

Communication Contents: UGI HAS COMPLETED OUR SYSTEM SURVEILLANCE PLAN, A COPY OF WHICH IS ENCLOSED. THE PLAN IS DESIGNED TO BE A CONSOLIDATION OF VARIOUS UGI PROGRAMS INTO A SINGLE DOCUMENT DESIGNED TO PROVIDE GUIDANCE AND EVALUATION CRITERIA TO AREA ENGINEERING AND FIELD PERSONNEL TO ASSURE EFFECTIVE AND CONSISTENT EVALUATION OF OUR DISTRIBUTION SYSTEM. THE MANUAL WAS DISTRIBUTED TO OUR AREA PERSONNEL ON DECEMBER 14, 1993.

Addressee Organization Type: P-Private Industry

Communication Date: 1992-11-23

Communication Type: Official Correspondence

Communication Contents: THE BOARD IS PLEASED TO LEARN THAT THE UGI WILL CONSOLIDATE ITS EXISTING PROGRAMS INTO A SYSTEM SURVEILLANCE PLAN WHICH WILL PROVIDE GUIDANCE & EVALUATION CRITERIA TO UGI PERSONNEL TO ENSURE EFFECTIVE & CONSISTENT EVALUATION OF THE UGI GAS DISTRIBUTION SYSTEM. THE UGI ALSO INTENDS TO REFERENCE THIS PLAN IN ITS REVISED MANUAL OF STANDARD PROCEDURES. RECOMMENDATION P-91-14 HAS BEEN CLASSIFIED "OPEN--ACCEPTABLE RESPONSE" PENDING OUR RECEIPT OF THE SYSTEM SURVEILLANCE PLAN & THE REVISED MANUAL OF STANDARD PROCEDURES.

Addressee Organization Type: P-Private Industry

Communication Date: 1994-04-22

Communication Type: Official Correspondence

Communication Contents: THE BOARD HAS REVIEWED THE UGI SYSTEM SURVEILLANCE PLAN, WHICH WAS INCLUDED WITH MR. CHANEY'S RESPONSE. THE PLAN INCLUDES PROCEDURES FOR COLLECTING, MONITORING, TRACKING, & ANALYZING DATA RELATED TO THE UGI GAS DISTRIBUTION SYSTEM & ASSOCIATED FACILITES. FURTHERMORE, THE IMPLEMENTATION OF THESE PROCEDURES IS PERFORMED BY PERSONNEL RESPONSIBLE FOR THE DESIGN, MAINTENANCE, & OPERATION OF THE GAS DISTRIBUTION SYSTEM. BASED ON UGI'S EFFORTS TO DEVELOP & IMPLEMENT A RESPOSIVE PLAN, P-91-14 HAS BEEN CLASSIFIED "CLOSED--ACCEPTABLE ACTION."

Addressee Organization Type: P-Private Industry

Communication Date: 1992-01-28

Communication Type: Official Correspondence