DOC ID© Chevron 2005

Pipeline Pigging Incident

Dave Shepherd

Aug, 2005

2DOC ID© Chevron 2005

What is a Pipeline Pig?

Used to clean or inspect pipelines that are in service.

Commonly used for:

Paraffin removal

Corrosion Inhibition

Pipeline Suspension

3DOC ID© Chevron 2005

Background

Two workers were attempting to remove a pig from a line that was launched the previous day.

Found pig was stuck in reducer section but cleared block valve so valve could be closed.

After depressuring pig receiver and opening it to atmosphere, both workers believed energy had been removed. Pig had to be pulled into pig receiver through the reducer to remove so they fashioned a hook from some ss tubing.

Receiver Reducer Ball Valve

Open to Atmosphere

4DOC ID© Chevron 2005

Incident

When worker hooked onto pig, the pig shot out and struck him in the nose resulting in major facial injuries.

Apparently, part of the pig created a seal with a weld in the reducer section, which created a pressure trap behind the pig.

5DOC ID© Chevron 2005

Injured Worker

August 1, 2005July 27, 2005

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Facial Reconstruction

8 hour procedure

7 plates (Titanium and Stainless Steel) used to reconstruct nose, eye sockets, and cheekbones.

Held together with 39 screws.

Jaw wired shut 2 – 4 weeks.

Expected to make full recovery.

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Other Factors

Safety glasses were not damaged but covered in oil and water. Likely prevented any chemical damage to eyes.

Trapped pressure was just high enough to create a seal but too low to move pig on its own. If pressure was lower or higher, incident would not have occurred.

Root cause was in hazard recognition. Neither worker considered any pressure existed since the pipe was open to atmosphere.