Managing overpressure of actuator shut down systems

What happened?

The actuator end cap for an emergency shutdown parted from the main housing during emergency shutdown system testing.
It travelled 150 feet/45 meters before stopping near the well head.
There were no injuries or environmental impact, but someone could have been seriously injured or killed if they were in the line of fire.
Why did it happen?

The actuator gas supply was set at 200 psi (nitrogen gas), but the actuator maximum allowable working pressure was 116 psi.
The gas supply and actuator housing emergency shutdown systems did not include over pressure safety protection.
What did they learn?

Identify line of fire hazards for pressure testing operations.
Establish and abide buffer zones for pressure testing activities.
Supply gas system designs should include multiple regulators to step down pressures.
Supply gas system designs should include pressure safety devices to protect entire system and components.
Ask yourself or your crew

What other actions could have been taken?
How could something similar happen here?
How confident are we that the design of our equipment can withstand over pressurisation?
How can we ensure we are not in the line of fire?
What can we do differently today?

Published on 01/04/19 3728 Views

The actuator end cap for an emergency shutdown parted from the main housing during emergency shutdown system testing... Someone could have been seriously injured or killed if they were in the line of fire.