In fact, employees who operate and know the dangers involved with the systems often do not understand the causes of water hammer. Incidents were reviewed if they resulted in, or had the potential to cause, employee injury due to a breach in a steam or condensate system. While the Hanford report focuses on steam system operations, the report pointed to other types of systems that have the potential to affect employees involved with them similarly. Both primary and contributing causes are listed below. For example, the valve that failed at the Hanford incident was constructed of gray cast iron with less than the expected tensile strength.
Cast steel is the preferred material for such components.
In addition, some systems are compromised further by not being subject to water chemistry control requirements during their early years and by inattention to routine maintenance. When these blockages broke loose, live steam flowed from the valve. Although no one was seriously injured in these incidents, there was potential for serious injury or property damage. These tests should be conducted under special controls and after all nonessential personnel have left the area. Lessons Learned Workshops DOE's Office of Environment, Safety and Health has conducted two workshops at Hanford to help prevent additional water hammer incidents from occurring.