Gallagher Fluid Seals recently added the Rubber Expansion Joint Surveys & Failure Analysis white paper to our Resources page. This white paper discusses the importance of inspecting your plant’s expansion joints. Proper design and maintenance of rubber expansion joints plays a major role in the overall preservation and lifespan of a piping system.
It will also discuss failure analysis of rubber expansion joints and some of the leading causes of joint failure.
An expansion joint can relieve stress in piping systems and prevent flange gaskets from being crushed. But which expansion joint is best for your specific application? Let us first describe the two types of expansion joints:
Rubber — a flexible connector fabricated of natural and/or synthetic elastomers and fabric and, if necessary, internal metallic reinforcements designed to provide stress relief in piping systems due to thermal movements and mechanical vibration.
Metal — a flexible element (bellows) constructed of relatively thin gauge material (generally stainless steel) designed to absorb mechanical and thermal movements expected in service.
Advantages: Metal Expansion Joints
Rubber joints with standard construction and materials have an upper range to 230°F. Most manufacturers, however, can offer special constructions up to 400°F. Metal expansion joints do offer a far greater range, from -420°F to +1800°F. However, working pressures are reduced at elevated temperatures.
Gallagher recently released its Expansion Joint Design Guide, now available for download on our site. This design guide takes an in-depth look at elastomeric, metal, and flue duct expansion joints. The excerpt below is the first section of our Expansion Joint Design Guide, diving into elastomeric expansion joints, and what to consider when selecting which joint is right for your application. To download the entire guide, visit our Resources Page, or click on the image to the right.
What is an Expansion Joint?
An expansion joint is a specially engineered product inserted in a rigid piping system to achieve one or more of the following:
Relieve system strain due to thermal change
Reduce mechanical noise
Compensate for misalignment
Eliminate electrolysis between dissimilar metals (metal expansion joints)
They are built to expand, contract, and adjust without straining or breaking the piping or ducting on either side. Essentially, an expansion joint is meant to protect the piping system from damage.