# NTSB Safety Recommendation P-91-012 - **operation:** document - **citation:** P-91-012 - **title:** NTSB Safety Recommendation P-91-012 - **source type:** guidance - **agency:** National Transportation Safety Board - **status:** guidance - **official:** true - **published on:** 1991-08-06 - **effective on:** 1991-08-06 - **summary:** THE NTSB RECOMMENDS THAT THE RESEARCH & SPECIAL PROGRAMS ADMINISTRATION: REQUIRE EACH GAS OPERATOR TO IMPLEMENT A PROGRAM, BASED ON FACTORS SUCH AS AGE, PIPE DIAMETER, OPERATING PRESSURE, SOIL CORROSIVENESS, EXISTING GRAPHITIC DAMAGE, LEAK HISTORY, BURIAL DEPTH, & EXTERNAL LOADING, TO IDENTIFY & REPLACE IN A PLANNED, TIMELY MANNER CAST-IRON PIPING SYSTEMS THAT MAY THREATEN PUBLIC SAFETY. - **machine formats:** - **json:** https://regulus.evalyn.ai/document/ntsb-recommendation-p-91-012.json - **markdown:** https://regulus.evalyn.ai/document/ntsb-recommendation-p-91-012.md - **app url:** https://regulus.evalyn.ai/document/ntsb-recommendation-p-91-012 - **source url:** https://data.ntsb.gov/carol-main-public/sr-details/P-91-012 **body:** NTSB safety recommendation P-91-012. THE NTSB RECOMMENDS THAT THE RESEARCH & SPECIAL PROGRAMS ADMINISTRATION: REQUIRE EACH GAS OPERATOR TO IMPLEMENT A PROGRAM, BASED ON FACTORS SUCH AS AGE, PIPE DIAMETER, OPERATING PRESSURE, SOIL CORROSIVENESS, EXISTING GRAPHITIC DAMAGE, LEAK HISTORY, BURIAL DEPTH, & EXTERNAL LOADING, TO IDENTIFY & REPLACE IN A PLANNED, TIMELY MANNER CAST-IRON PIPING SYSTEMS THAT MAY THREATEN PUBLIC SAFETY. Priority: CLASS II Overall Status: Closed - Acceptable Alternate Action Issued Date: 1991-08-06 Adopted Date: 1991-07-23 Overall Date Closed: 1992-10-28 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: RSPA Addressee Status: Closed - Acceptable Alternate Action Addressee Date Closed: 1992-10-28 Addressee Acronym: RSPA Addressee Organization Type: G-Federal Government Communication Date: 1992-10-28 Communication Type: Official Correspondence Communication Contents: THE BOARD APPRECIATES RECEIVING A COPY OF THE PIPELINE SAFETY ALERT NOTICE ISSUED BY THE RSPA ON 6/26/92, THAT SUPPLEMENTS THE RSPA'S 10/11/91, ALERT NOTICE CONCERNING CAST-IRON PIPE. THE NEW ALERT NOTICE EMPHASIZES THAT EACH OPERATOR IS REQUIRED TO HAVE A PROCEDURE FOR CONTINUING SURVEILLANCE OF ITS PIPELINE FACILITIES, INCLUDING CAST-IRON PIPE, TO IDENTIFY PROBLEMS & TAKE APPROPRIATE ACTION CONCERNING FAILURES, LEAKAGE HISTORY, CORROSION, & OTHER UNUSUAL OPERATING & MAINTENANCE CONDITIONS. THE ALERT NOTICE ALSO POINTS OUT THAT IF A SEGMENT OF PIPELINE, INCLUDING A CAST-IRON SEGMENT, IS DETERMINED TO BE IN UNSATISFACTORY CONDITION BUT NO IMMEDIATE HAZARD EXISTS, THE OPERATOR SHALL INITIATE A PROGRAM TO RECONDITION OR PHASE OUT THE SEGMENT INVOLVED. AS A RESULT OF THE CONFERENCE BETWEEN OUR STAFFS ON 1/7/92, & THE SUBSEQUENT DEVELOPMENT OF THE 6/26/92, ALERT NOTICE, RECOMMENDATION P-91-12 HAS BEEN CLASSIFIED AS "CLOSED--ACCEPTABLE ALTERNATE ACTION." Addressee Acronym: RSPA Addressee Organization Type: G-Federal Government Communication Date: 1991-10-11 Communication Type: Official Correspondence Communication Contents: From George W. Tenley, Associate Administrator, Office of Pipeline Safety: NTSB Recommendation S P-91-12, 07/90 Allentown, PA: replacement of cast-iron piping. RSPA/gas operators should have a program to identify/replace cast iron systems that threaten public safety. AGA recently sent materials to cast iron operators to assist their program. Alert Notice: ALN-91-02 Date: 10/11/91 To: Subject: Each Owner or Operator of a Gas Pipeline Facility and Every State Pipeline Safety Representative Purpose: NTSB recently issued recommendation P-91-12 related to the August 1990 explosion and fire in Allentown, PA, caused by a crack in a 4-inch cast iron gas main. Recommendation P-91-12 states: Notice: Background: NTSB recently issued recommendation P-91-12 related to the August 1990 explosion and fire in Allentown, PA, caused by a crack in a 4-inch cast iron gas main. Recommendation P-91-12 states: Require each gas operator to implement a program, based on factors such as age, pipe diameter, operating pressure, soil corrosiveness, existing graphitic damage, leak history, burial depth, and external loading, to identify and replace in a planned, timely manner cast iron piping systems that may threaten public safety. RSPA is equally concerned that each gas pipeline operator have a program to identify and replace those cast iron piping systems that may threaten public safety. The American Gas Association (AGA) has recently sent material that has been developed by the Gas Piping Technology Committee (GPTC) to all pipeline distribution operators with cast iron pipe to assist them in developing procedures for determining the serviceability of the cast iron pipe and to identify the cast iron pipe segments that may need replacement. This GPTC material identifies all of the same factors set forth in the NTSB recommendation that should be considered in a cast iron pipe replacement program. RSPA supports the use of these factors in determining the cast iron pope segments that may need replacement. If an operator has cast iron pipe and has not received the material, contact either Larry Ingels (703/804-8454) or John Erickson (703/841-8612) of AGA and request the information. Operators should be aware that computer programs are commercially available that can be used to develop a systematic replacement program for cast iron pipe. One of these programs is the Cast-Iron Maintenance Optimization System (CIMOS) developed through research sponsored by the Gas Research Institute. Current pipeline safety regulations require that cast iron pipe on which general graphitization is found to a degree where a fracture might result, must be replaced. In addition, the regulations require that cast iron pipe that is excavated must be protected against damage. An operator's compliance with these requirements can be enhanced by incorporating all of the operator's cast iron responsibilities in an effective cast iron program that is designed to identify and replace cast iron pipe that may threaten the public. Addressee Acronym: RSPA Addressee Organization Type: G-Federal Government Communication Date: 1992-09-03 Communication Type: Official Correspondence Communication Contents: THIS IS A FOLLOW-ON TO OUR LETTER OF OCTOBER 22, 1991, AND A CONFERENCE OF OUR RESPECTIVE STAFFS ON JAN. 7, 1992, REGARDING NTSB SR P-91-12. WE HAVE ALSO ISSUED AN ALERT NOTICE DATED JUNE 26, 1992, SUPPLEMENTING THE ALERT NOTICE CONCERNING CAST IRON THAT WAS ISSUED ON OCTOBER 11, 1991, THAT POINTS OUT THIS REGULATORY REQUIREMENT. Addressee Acronym: RSPA Addressee Organization Type: G-Federal Government Communication Date: 1992-08-31 Communication Type: Official Correspondence - **truncated:** false - **body characters:** 6863