Troubleshooting Field Failures of Rupture Disks

    Even with the best process design, the unexpected can happen. Anticipating this, rupture disks are often installed as the last line of defense against the over-pressurization of equipment used for the manufacture, transport and storage of many types of chemicals, petrochemicals, medicines, plastics, powders, food and beverages. When handled and installed properly, rupture disks are a safe and economical means to protect people, equipment and processes. When they work well, rupture disks can provide safety against catastrophic equipment failure and personal injury from unexpected events, such as explosions, control failures, power outages, runaway reactions, external fires and blocked valves. (For more on general safety issues, see Part 1 of this report, p. 30.) Quite often when a disk does not work as expected, the cause can be extremely frustrating to diagnose because the ruptured disk relieves the pressure condition that caused the rupture, and the disk’s energy release can erase clues that can help identify the root cause. Here we examine the more common causes for disk ruptures, based on our troubleshooting experience. Consideration of these causes can help identify and eliminate potential problems that could…