NTSB Safety Recommendation P-71-008

NTSB safety recommendation P-71-008.

THE NTSB RECOMMENDS THAT THE OFFICE OF PIPELINE SAFETY OF THE DEPARTMENT OF TRANSPORTATION TAKE THE FOLLOWING ACTION: CLARIFY THE FEDERAL REGULATIONS PERTAINING TO THE DETERMINATION OF MAXIMUM ALLOWABLE OPERATING PRESSURE FOR EXISTING PIPELINES SO THAT THE JOINT FACTOR IN USE WHEN THE PIPE WAS MANUFACTURED IS UTILIZED FOR CURRENT COMPUTATIONS.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 1971-07-01

Adopted Date: 1971-07-01

Overall Date Closed: 1976-09-10

Synopsis: ON SEPTEMBER 9, 1969, A 14-INCH PIPELINE CARRYING NATURAL GAS AT A PRESSURE OF MORE THAN 780 P.S.I.G. RUPTURED IN A RESIDENTIAL SUBDIVISION 3 1/4 MILES NORTH OF HOUSTON, TEXAS. ALL RESIDENTS WERE EVACUATED, AND ABOUT 8 TO 10 MINUTES LATER, THE ESCAPING GAS EXPLODED VIOLENTLY. THIRTEEN HOUSES, RANGING FROM 24 FEET TO 250 FEET FROM THE RUPTURE, WERE DESTROYED BY THE BLAST. THE LEAKING GAS CAUGHT FIRE AND BURNED FOR 1 1/2 HOURS UNTIL VALVES ON EITHER SIDE OF THE LEAK WERE CLOSED BY MOBIL WORKMEN. IN ALL, 106 HOUSES WERE DAMAGED, AND PROPERTY DAMAGE WAS ESTIMATED AT $500,000. MIRACULOUSLY, THERE WERE NO DEATHS, BUT 9 PEOPLE WERE INJURED, 2 SERIOUSLY.

Ntsbnumber: PLD69XR001

Report Number: PAR-71-01

Addressee Name: RSPA

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 1976-09-10

Addressee Acronym: RSPA

Addressee Organization Type: G-Federal Government

Communication Date: 1976-03-09

Communication Type: Official Correspondence

Communication Contents: 2/24/72 - LETTER FROM DOT: AN AMENDMENT TO CLARIFY THE REGULATIONS IS BEING PREPARED AND WILL BE ISSUED IN A FEW WEEKS. 3/9/76 - STATUS REPORT FROM OPS STATED: FEBRUARY 26, 1972, LETTER FROM ASME GAS PIPING STANDARDS COMMITTEE JUSTIFIED THE REASON FOR USING A JOINT FACTOR OF 1.0 INSTEAD OF 0.85. THIS WAS BASED UPON THE FACT THAT SINCE 1932, THE API PIPE SPECIFICATIONS REQUIRE A TRANSVERSE WELD TEST FOR ERW PIPE. CORRESPONDENCE DOCUMENTATION INCOMPLETE.