# NTSB Safety Recommendation P-79-024

- **operation:** document
- **citation:** P-79-024
- **title:** NTSB Safety Recommendation P-79-024
- **source type:** guidance
- **agency:** National Transportation Safety Board
- **status:** guidance
- **official:** true
- **published on:** 1979-08-08
- **effective on:** 1979-08-08
- **summary:** THE NTSB RECOMMENDS THAT THE NATURAL GAS PIPELINE COMPANY OF AMERICA: IDENTIFY CONTOUR AREAS WHERE VERTICAL OR HORIZONTAL BENDS IN THE PIPELINE MAY EXIST, AND EXCAVATE, ON A RANDOM BASIS ACCEPTABLE TO THE APPROPRIATE STATE AGENCIES, TO DETERMINE IF COMPRESSION COUPLINGS LOCATED ADJACENT TO THESE BENDS HAVE EXPERIENCED EXCESSIVE AXIAL FORCES THAT COULD CAUSE A COUPLING FAILURE. INSTALL SUITABLE STRAPPING OR SLEEVING O
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- **source url:** https://data.ntsb.gov/carol-main-public/sr-details/P-79-024
**body:**

NTSB safety recommendation P-79-024.

THE NTSB RECOMMENDS THAT THE NATURAL GAS PIPELINE COMPANY OF AMERICA: IDENTIFY CONTOUR AREAS WHERE VERTICAL OR HORIZONTAL BENDS IN THE PIPELINE MAY EXIST, AND EXCAVATE, ON A RANDOM BASIS ACCEPTABLE TO THE APPROPRIATE STATE AGENCIES, TO DETERMINE IF COMPRESSION COUPLINGS LOCATED ADJACENT TO THESE BENDS HAVE EXPERIENCED EXCESSIVE AXIAL FORCES THAT COULD CAUSE A COUPLING FAILURE. INSTALL SUITABLE STRAPPING OR SLEEVING ON COUPLINGS WHICH DO NOT PASS REINSPECTION BECAUSE OF LEAKAGE, CORROSION, OR EVIDENCE OF PARTIAL PULLOUT. (URGENT)

Priority: CLASS I

Overall Status: Closed - Acceptable Action

Issued Date: 1979-08-08

Adopted Date: 1979-07-19

Overall Date Closed: 1979-09-19

Synopsis: ON APRIL 18, 1979, A 24-INCH NATURAL GAS TRANSMISSION PIPELINE OWNED BY THE NATURAL GAS PIPELINE COMPANY OF AMERICA (GAS COMPANY) PULLED OUT OF A COMPRESSION COUPLING DURING A LINE-LOWERING PROJECT UNDER IOWA STATE HIGHWAY 181 IN A RURAL AREA NEAR DALLAS, IOWA. WITHIN SECONDS, THE NATURAL GAS IGINITED AND BURNED A 900-FOOT BY 400-FOOT AREA. FIVE OF THE EIGHT INJURED WORKERS WERE HOSPITALIZED. TWO CARS, A PICKUP TRUCK, AND A TRAILER HOUSING CONSTRUCTION EQUIPMENT WERE DESTROYED. A BACKHOE WAS PARTLY DAMAGED, AND WINDOWS WERE BROKEN IN A NEARBY FARMHOUSE.

Ntsbnumber: DCA79FP013

Report Number: None

Addressee Name: Natural Gas Pipeline Company of America

Addressee Status: Closed--No Longer Applicable

Addressee Date Closed: 1979-09-19

Addressee Acronym: NGPL

Addressee Organization Type: P-Private Industry

Communication Date: 1979-08-23

Communication Type: Official Correspondence

Communication Contents: NATURAL GAS PIPELINE COMPANY OF AMERICA LTR: A MASSIVE PROGRAM HAS BEEN INITATED TO LOCATE VERTICAL AND HORIZONTAL BENDS IN THE PIPELINE. EARLY STAGES WILL BE IN IOWA ONLY BECAUSE OF THE ACCIDENT RECORD. IT WILL EXPAND INTO OTHER STATES. AT EACH LOCATED BEND, THE DEPTH OF COVER AND DEGREE OF BEND ARE MEASURED. THE POSSIBILITY OF A NET UNBALANCED FORCE EXISTING UNDER WORST CONDITIONS IS CALCULATED. WHERE PROBLEMS ARE FOUND, ANCHORS AND SLEEVES WILL BE APPLIED. COUPLINGS ADJACENT TO BENDS WILL BE EXPOSED ON A RANDOM BASIS FOR VISUAL INSPECTION. WHERE THERE IS EVIDENCE OF PARTIAL PULLOUT, RADIOGRAPHY WILL BE USED TO DETERMINE THE LOCATION OF THE PIPE IN THE COUPLING. REINFORCING SLEEVES WILL BE USED WHERE CORRECTIVE ACTION IS NEEDED. AS OF AUGUST 17, 1979, 57 LOCATIONS WERE IDENTIFIED IN IOWA AS SITES WHERE REMEDIAL WORK MAY BE BENEFICIAL, AND WORK HAS BEEN COMPLETED AT 28 OF THESE.

Addressee Acronym: NGPL

Addressee Organization Type: P-Private Industry

Communication Date: 1979-09-19

Communication Type: Official Correspondence
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