Explosion in a Gas Processing Plant

Fire and Explosion in a Gas Processing Plant

What happened?

Fire and explosion has occurred in the Storm Water Drain (SWD) in a gas processing plant that resulted in one fatality, 32 workers hospitalized and damages to the SWD structure. Fire occurred while a worker was testing his welding equipment (amperage test) on a working platform about 6 meters above the SWD. Investigation revealed that the fire was initiated from the welding sparks, which fell into the SWD that contained flammable hydrocarbons [fuel] in excess quantity and led to an explosion and fire.

 
Picture 1 : A: Working Area; B: Condition inside SWD with burnt marks after the explosion and fire

What went wrong?

• The plant owner failed to identify hazards and risk of hydrocarbons in the SWD;
• Tests to confirm that the plant is hydrocarbons free does not include SWD;
• Failure of the owner to carry out periodic maintenance work on the SWD;
• No safety procedure in carrying out welding work;
• The scope of the gas measurement is not carried out properly because it does not consider risk assessment of welding work’s surrounding;
• Communications breakdown within organization during safety management implementation; and
• Measurement of Lower Explosion Limit (LEL) for hydrocarbons in the SWD was not carried out by the owner.

Lessons Learnt

• Identification of hazards and risk must be done thoroughly, including SWD;
• Test shall be taken to ensure SWD is hydrocarbons free;
• Periodic maintenance work should be carried out on the SWD to ensure no presence of hydrocarbons in it;
• Provision of safe work procedures for welding work;
• The scope of the gas measurement should take into account the environmental risk assessment for welding work;
• Effective communication in the organization is upheld during the implementation of safety management system and
• Measurement of Lower Explosion Limit (LEL) for hydrocarbons in the SWD should be carried out by the owner.

References

1. Bjerketvedt, D., Bakke, J.R., Wingerden, K.V. 1997. Gas explosion handbook. Journal of Hazardous Materials 52: 1-150
2. Lees, F.P. 1996. Loss Prevention in the Process Industries – Hazards Identification, Assessment And Control, Volume 2, 2^nd edition, Butterworth-Heinemann, Oxford, United