In the safety message, Bresland warned that without appropriate safeguards, pressure vessels can pose lethal dangers. “Pressure vessels store tremendous amounts of energy and you should never become complacent about the risks,” he said.
Particular danger exists when vessels are improperly installed, welded or modified or when they lack effective pressure relief systems. Bresland referred to several incidents investigated by CSB, including:
- An explosion at a Louisiana natural gas well that killed four workers when a tank rated only for atmospheric pressure was exposed to gas pressure up to 800 pounds per square inch.
- An April 2003 fatal incident, where an 8-foot tank used to heat sugar caramel exploded when the vent line became blocked. The explosion killed an overnight operator, released large amounts of ammonia and forced a community evacuation. The vessel had no pressure-relief system.
- A pressure vessel weighing 50,000 pounds exploded in 2004 at a chemical plant in Houston, Texas, throwing heavy fragments into the community and damaging a church and businesses. CSB found that the company improperly modified and welded the vessel.
Bresland stated that these accidents can be avoided if states implement long-established codes for safe use.
“There are only 11states that do not require companies to follow the Pressure Vessel Code of the American Society of Mechanical Engineers (ASME),” he said. “I ask all jurisdictions to adopt the Pressure Vessel Code and related boiler standards. Lives will be saved as a result.”
The ASME Code provides the fundamental safeguards for pressure vessels, including design, welding procedures and fabrication, testing and pressure relief. In 2006, CSB called upon the City of Houston to adopt the code to protect residents and industrial facilities from these incidents. According to CSB, however, Houston has failed to implement this recommendation despite reoccurring pressure vessel failures, such as a summer of 2008 heat exchanger explosion in a resin-production facility that killed a veteran supervisor.