Leakage costs industry millions of dollars every year. For example, a few small leaks in a facility using air at 100 psig, with an electric consumption cost of about 6¢/kWh, can waste more than $22,000 annually. Delaying the replacement of a leaking $100 steam trap could waste $50 per week; since an average facility typically has hundreds of steam traps throughout its operations, leaking traps may be squandering hundred of thousands of dollars each year. In addition to wasted dollars, unattended leaks can result in downtime, affect product quality, pollute the environment, and cause injury.
The following discussion is aimed at minimizing leakage from process-piping, analytical-instrumentation, and utility lines, such as those for steam and compressed air. Such connections are typically within the size range of 1/16 to 2 in. (2–50 mm). (For a detailed look at flanged connections with gasket or O-ring seals, see CE, June 2005, pp. 38–45).
Causes of leakage
System vibration, pulsation, and thermal cycling are all common causes for chemical-processing-system leakage.
One can assume that any type of fitting connection may leak, regardless of whether pipe or tube is used, especially when mechanical vibration…