Another Costly Gasket Error

It is disappointing, but the compressed asbestos gasket has no universal substitute. In many cases, it requires two, three, or more different, limited-application substitutes. Many substitute gaskets will cost between three and ten times more than the compressed asbestos they replace. 

A petroleum refinery was in the process of phasing out compressed asbestos gaskets to conform to new U.S. laws. Asbestos gaskets had been used for years without any sig-nificant problems. During the conversion the company mistakenly assumed the nonasbestos substitute gasket would seal out the same fluids as the asbestos products if the gaskets were used within the manufacturer s temperature limitations. 

Regrettably, a refinery worker was injured by sulfuric acid because a 4-inch (10 cm) piping substitute gasket failed. The acrylic fibers in the nonasbestos gasket material were attacked by the acid. The asbestos fibers had resisted the chemical attack. 

Over 20 years ago, a thrifty purchasing agent for a large chemical complex was con-cemed about the high prices of stud bolts that were coated with aplastic-like finish to inhibit rusting. He learned that cadmium-coated studs and nuts were available at more economical prices. 

The alert mechanic informed the operations supervisors of the failures. Operations shut down the furnace. Maintenance mechanics replaced the bolts with the proper specified, high-strength stud bolts prior to any serious releases. 

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