A Y-shaped strainer (filter) in a three-inch pipe ruptured. The failure occurred after pressure cycles induced by thermal expansion. The released isobutylene resulted in a gas cloud explosion and the company's bankruptcy.
Aspects:
- When a closed system filled with a liquid hydrocarbon raises the temperature, the pressure can rise above the design.
- Here, a brittle fatigue failure occurred in the strainer made from iron cast. More ductile materials are recommended for systems that handle hazardous materials under pressure.
- Sometimes, valves are made locked open to allow for expansion.
- Thermal relief valves can be added to a system that might be full of liquid and blocked by closed valves.
- Establish criteria for each plant when thermal relief valves have to be included – depending on volume, liquid, construction material, and expected temperature changes.
