Steam Water Hammer Accident Investigation and Steam Training
Wayne Kirsner, P.E. / Principal
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Photo 1-6. Example of slip condition at EJ-18. (A-1165) Slips for expansion joints are constructed of chrome. They should be maintained bright and shiny as they came from the factory in order to limit corrosion and friction. But HYSPAN, the manufacturer of the joints, does claim that the joints are maintenance free. I don’t believe however, the manufacturer had the severe environment of this tunnel system in mind when claiming that the joints are maintenance free. Nevertheless, the manufacturer appears to be confident that even a joint looking like that above, as long as it is not internally corroded, should function if properly installed. In fact, as I understand it, warranty it for 5 years. Nonetheless, recommend that the slips of all expansion joints be cleaned to bright shiny metal each year when the system goes cold (at which time the slips are maximally exposed) and inspected every time the system goes cold. (Some major manufactures require this to maintain the 5-year warranty on the joints.) Also, recommend one joint thought to be seized be returned to the manufacturer for test. It is important to know if internal corrosion is causing joints to seize. |
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