NTSB Safety Recommendation P-92-004

NTSB safety recommendation P-92-004.

THE NTSB RECOMMENDS THAT THE OKLAHOMA NATURAL GAS COMPANY: REQUIRE SERVICE REGULATOR TECHNICIANS TO TEST REGULATOR RELIEF VALVES WHEN PERFORMING MAINTENANCE TESTS OR RECONDITIONING REGULATORS TO DETERMINE THAT THESE VALVES OPERATE ACCORDING TO THE MANUFACTURER'S SPECIFICATIONS.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 1992-04-29

Adopted Date: 1992-04-09

Overall Date Closed: 1995-08-21

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: 1995-08-21

Addressee Acronym: Oneok

Addressee Organization Type: P-Private Industry

Communication Date: 1995-08-21

Communication Type: Official Correspondence

Communication Contents: THE BOARD UNDERSTANDS THAT SERVICE REGULATOR TECHNICIANS TEST REINSTALLED REGULATOR RELIEF VALVES TO DETERMINE THAT THE VALVES ARE OPERATING TO SPECIFICATION. BASED ON THIS INFO P-92-4 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: SERVICE REGULATOR TECHNICIANS WILL TEST REGULATOR RELIEF VALVES THAT ARE TO BE REINSTALLED WHEN PERFORMING MANDATORY TESTS OR RECONDITIONING REGULATORS TO DETERMINE TO DETERMINE THAT SUCH VALVES OPERATE ACCORDING TO MANUFACTURER'S SPECIFICATION. IT WILL NOT BE BENEFICIAL TO TEST RELIEF VALVES ON THE REGULATORS THAT ARE BEING JUNKED SINCE THEY WILL BE REMOVED DURING MAINTENANCE OR SERVICE CALLS. THE OTHER REGULATORS THAT HAVE INTERNAL SPRING-LOADED REIEF VALVES WILL BE TESTED AS THEY ARE RECONDITIONED IN THE SHOP.

Addressee Acronym: Oneok

Addressee Organization Type: P-Private Industry

Communication Date: 1992-07-16

Communication Type: Official Correspondence