NTSB Safety Recommendation P-92-002

NTSB safety recommendation P-92-002.

THE NTSB RECOMMENDS THAT THE OKLAHOMA NATURAL GAS COMPANY: CONDUCT A ONE-TIME INSPECTION OF FISHER TYPE 733A AND OTHER GAS SERVICE REGULATORS WITH ADJUSTABLE RELIEF VALVES TO DETERMINE WHETHER THE RELIEF VALVES ARE PROPERLY ADJUSTED TO PROTECT DOWNSTREAM GAS PIPING FROM EXCESSIVE PRESSURES AND CORRECT DEFICIENT CONDITIONS.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 1992-04-29

Adopted Date: 1992-04-09

Overall Date Closed: 1995-12-12

Synopsis: AT 7:02 P.M. CENTRAL STANDARD TIME ON JULY 5, 1991, AT TULSA, OKLAHOMA, HIGH-PRESSURE GAS ENTERED A LOW-PRESSURE, SINGLE-FAMILY CUSTOMER-SERVICE LINE CONNECTED TO A GAS METER AND REGULATOR IN A BURIED CONCRETE BOX NEAR THE CUSTOMER'S FRONT PROPERTY LINE. GAS AT 40-PSIG PRESSURE WAS SUPPLIED TO THE REGULATOR AND METER AT 3805 EAST 98TH STREET FROM A 2-INCH-DIAMETER PLASTIC GAS MAIN AND A 1 1/4-INCH-DIAMETER PLASTIC SERVICE LINE. THE HIGH-PRESSURE GAS ENTERED THE GAS FUEL LINES AND APPLIANCES RESULTING IN THE ESCAPE OF GAS INTO THE HOUSE. THERE WERE NO INJURIES, BUT THE GAS ESCAPING FROM THE FURNACES AND THE WATER HEATER IGNITED AND FUELED FIRES THAT DESTROYED THE MULTILEVEL HOUSE. PROPERTY DAMAGE WAS ESTIMATED BY THE TULSA FIRE DEPARTMENT AT 540,000.

Probable Cause: Failure to ensure that the gas service regulator safety relief valve was adjusted properly

Ntsbnumber: DCA91FP009

Report Number: None

Addressee Name: Oklahoma Natural Gas Corporation

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 1995-12-12

Addressee Acronym: Oneok

Addressee Organization Type: P-Private Industry

Communication Date: 1995-08-21

Communication Type: Official Correspondence

Communication Contents: THE BOARD UNDERSTANDS THAT THE ONGC HAD INITIATED A PROGRAM TO REMOVE THE FISHER TYPE 733A & OTHER REGULATORS WITH EXTERNAL ADJUSTABLE RELIEF SETTINS. WE ALSO UNDERSTAND THAT THE ONGC IS PRESENTLY PERFORMING AN INTERNAL AUDIT TO ENSURE THAT ALL TO THESE TYPES OF REGULATORS HAVE BEEN REMOVED FROM SERVICE. PENDING COMPLETION OF THE AUDIT, P-92-2 IS CLASSIFIED "OPEN--ACCEPTABLE ALTERNATE RESPONSE."

Addressee Acronym: Oneok

Addressee Organization Type: P-Private Industry

Communication Date: 1995-12-12

Communication Type: Official Correspondence

Communication Contents: THE BOARD UNDERSTANDS THAT THE ONGC DEVELOPED AN EXTENSIVE PROGRAM TO REBUILD UNDERGROUND REGULATOR SETTINGS, INCLUDING THE FISHER 733A REGULATORS. BASED ON PERFORMANCE TO DATE & THE NEAR COMPLETION OF THE REBUILDING OF AT THE REMAINING REGULATORS P-92-2 IS CLASSIFIED "CLOSED--ACCEPTABLE ACTION."

Addressee Acronym: Oneok

Addressee Organization Type: P-Private Industry

Communication Date: 1995-06-19

Communication Type: Official Correspondence

Communication Contents: OKLAHOMA NATURAL GAS COMPANY IS PRESENTLY PERFORMING AN INTERNAL AUDIT OF OUR UNDERGROUND SETTINGS TO ASSURE THAT ALL FISHER 733A'S HAVE BEEN REMOVED FROM SERVICE.

Addressee Acronym: Oneok

Addressee Organization Type: P-Private Industry

Communication Date: 1995-09-14

Communication Type: Official Correspondence

Communication Contents: THE OKLAHOMA NATURAL HAS DEVELOPED AN EXTENSIVE PROGRAM TO REBUILD THE UNDERGROUND MEDIUM-PRESSURE METER/REGULATOR SETTINGS & WHENEVER POSSIBLE RAISE THE SETTINGS ABOVEGROUND. A TOTAL OF 1,011 SETTINGS WERE REBUILD & RAISED BETWEEN JULY 1992 & AUGUST 1995. OUT OF THE 1,011 SETTINGS REBUILTS, THE NUMBER OF FISHER 733A REGULATORS REMOVED IN UNDERGROUND METER/REGULATOR SETTINGS IS 447. THE TOTAL REMAINING FISHER 733A REGULATORS IN THE UNDERGROUND METER/REGULATORS SETTINGS IS 328. IN ADDITION, THE NUMBER OF DOMESTIC REGULATORS WITH EXTERNAL-ADJUSTABLE RELIEF SETTINGS REMOVED ON ROUTINE SERVICE CALLS IS 4,842.

Addressee Acronym: Oneok

Addressee Organization Type: P-Private Industry

Communication Date: 1992-07-16

Communication Type: Official Correspondence