Many members of the Fluid Sealing Association (FSA) Non-Metallic Expansion Joint Division and of the Expansion Joint Manufacturers Association (EJMA) feel that expansion joints are the forgotten components of many piping systems. Other piping systems components – flanges, gaskets, strainers, valves, pumps and the pipe itself – seem to get most of the design time.
In many ways, expansion joints are the most important components of a well-designed piping system. They are the “living and breathing” dynamic part of the whole system.
Without well-designed and well-placed expansion joints, parts such as pump nozzles, valve bodies and pipe anchors could face excessive loading and vibrational fatigue. Without proper compensation, thermal growth at elevated temperatures can damage some pipes, reducing their operation life.
The criteria for expansion joint selection for fluid piping applications focuses on the expansion joint’s quality, durability and capabilities. To ensure that the rubber expansion joint’s installation provides optimal service life, operators and maintenance personnel must consider specific conditions and take a systematic approach. Piping systems require some degree of flexibility. Inadequate flexibility can lead to a catastrophic, potentially life-threatening system failure, making flexibility an important consideration when selecting an expansion joint.
The fourth edition of the American Petroleum Institute (API) Standard 682 was released in May 2014. The May edition includes several updates to reflect the changing design and application needs of mechanical seals. Annex G defines several new piping plans and associated auxiliary hardware. Piping Plan 03 is defined as as dead-ended seal chamber with a tapered bore and no throat bushing. Tapered bore seal chambers are well-established in many industries. These designs have significant performance differences from traditional, closed-throat cylindrical bore seal chambers, which are defined separately in Piping Plan 02.
While defining all the possible causes of a failed expansion joint or pump flexible connector is important, doing everything possible to get it right the first time is equally important. This can save the end user money and time by delaying significant replacement costs and failures. All components and system requirements must be considered when choosing an expansion joint for the particular application. Uncovering all the factors that may influence reliable performance provides for the most ideal selection.