Pipeline Tie-In Activity, a Lesson Learned

The Accident Generalities Accident location: Pipeline Project, Nigeria Date of Accident: February 2012 Type of Activity: Pipeline Tie In Operation Accident brief description The activity planned was to cut off the test header from the 10 inches pipeline sections inside the trench and then to carry out the final golden weld. The operation was carried out by a pipefitter supervisor (the injured person) with the help of another pipefitter. The equipment used were a sideboom and a crane (see picture two), both positioned to hold the test header during the cut off operation. The operation was executed in a congested area: other pipes and wooden skids were already present into the trench. After alignment of pipes and measurement taken, the pipefitter supervisor started to cut the 10 inches pipeline test header by using radial oxy-cutting machine, with the help of the other pipefitter.

The Accident Before the end of machine cutting (approx 50 mm still to cut) the supervisor decided to use the manual cutting torch to complete the work. As soon as he was close to complete the cutting, the pipeline section, which was under physical tension, suddenly whipped (see picture one), hitting the supervisor at umbilicus region and trapping him between the pipe and the trench wall (see picture three) The pipefitter supervisor died in the hospital due to massive internal injuries; the other pipefitter suffered minor injuries being released from the hospital immediately.

Causes of Accident The Pipeline was under physical tension, due to torque created by sideboom’s slings holding the pipe and pushing towards the trench wall, while the crane slings were holding the test header The pipefitter supervisor didn’t properly assessed the position of the crane, sideboom ant trucks, in term of safety The workplace was congested no tie-in bell hole was present at accident location The pipeline section movement was not blocked as no pipe stoppers onto the timber skids and no other type of safeguards was present Injured person overconfidence: he placed himself in a unsafe position, in the most dangerous side to execute the final cut of the test header The permit to work was prepared by another person three days before the accident. The execution of the work resulted to be not in line with the activity described in the PTW. Method of statement and related risk assessment didn’t capture all the hazard relevant to specific tie-in activity.

Corporate Actions From Company Corporate side a dedicated procedure has been developed and issued in order to better define the roles, responsibilities, work process to manage the tie-ins operation in the onshore pipeline system transporting hydrocarbons and other fluids commonly used in the Oil & Gas industries. The following phases have been selected as a typical tie-in operation cycle to be followed by Contractor and Subcontractors, in order to ensure a safely and on timing completion of the activities Tie-in planning Tie-in classification Tie-in detail design phase Tie-in execution and HSE Requirements Tie-in hand over