Young worker dies after pressure testing oil field piping

In a welding shop, two workers pressurized two 16-inch "pig traps" (oil field piping) to 2,150 psi. This pressure test verified the welds on the pig traps. Then one of the workers, a young worker, started to disassemble the connection between the piping being tested and the pressure-recording device. However, he did not depressurize the piping pieces first. He used a pipe wrench to remove a test tee from a 1-inch ball valve that isolated the test tee from the piping pieces. The test tee did not unthread from the valve as expected. Instead, the valve itself unthreaded from the pipe nipple connecting the valve to the still-pressurized pig traps. As a result, the valve and the test tee shot upwards, striking the worker and causing serious injuries. He died in hospital after surgery.

Safe work practices:

• Ensure that a pressurized system is completely depressurized before carrying out any work on the system.
• Establish and enforce written safe work procedures for pressure-testing operations, including the following:

• a step-by-step process for pressurizing and depressurizing a system, including instructions for the required safety devices (pressure relief valve, pressure gauge, etc.)
• the number of workers needed to perform pressure tests safely
• the specific role of each worker during pressure testing
• Provide new and young workers with the required orientation and training. Keep records of all orientations and training.
• Provide workers with adequate supervision during pressure testing to ensure safety.