Fire And Explosion Of Natural Gas Pipeline In Sarawak
Fire and explosion of a 36" diameter natural gas pipelines occurred on June 10, 2014, at approximately 1.30 am. At about 5.00 am, the fire is extinguished after fuel sources of natural gas in the pipeline was thoroughly burned. This event does not result in any loss of life or injury to humans (public or worker). However, the impact from the explosion and fire formed a crater of about 10 metres in diameter and 3 metres depth. It also caused crops surrounding area of 500 metres radius from the center of the explosion to burnt out. During that time, there was no work activity is in progress, nor arson activity identified.
Radius of fire estimated about 100-150 metres.
This incident caused by the release of gas from the pipeline through a welded joint between two pipes. This failure was due to the low strain capacity of the girth weld at joint that was subjected to external loading (such as soil movement and vibration loads by heavy vehicle). Fracture at the weld joint was resulting from welding defects and flaws. Type of consumables (electrodes) used, expertise of welders and welding technique implemented caused this condition to happen. These inherent defects have not been identified and translated effectively through Non-Destructive Test (NDT) performed on respective welded joint.
From the results of the investigation made on these events, emphasis on the integrity of the welding should be given, particularly for welding works of the underground gas pipeline. Therefore, attentions to the following point must be considered:
- Preparation of a thorough and accurate Welding Procedure Specification (WPS) and Procedure Qualification Record (PQR) should consider all the elements requiredby the respective welding design code.
- The welding work carried out should be effectively and thoroughly supervised in ensuring compliance with welding techniques, procedures and materials used as specified in the provided WPS and PQR.
- A competent person must interpret and evaluate accurately and transparently the results of the non-destructive tests of welding conducted.
- The effectiveness and usability of a detection system of gas relief from underground gas pipelines and its control measures over such events should be provided and monitored from time to time.