A rubber expansion joint is a structural flange that provides support to two or more parts of a building. It is a common option in a range of construction projects, from small home improvements to major commercial projects. However, its performance depends on its design, application, and production process. To ensure that your new expansion joint meets all your requirements, it is important to make sure that you select a design that is optimized for your current design and manufacturing process.
Limitations of rubber expansion joints
There are several limitations when using rubber expansion joints in structural applications. These limitations include the type of elastomer and reinforcement required, the thickness of the materials, and the external environment. The material type and environment should guide the selection of the type of expansion joint. Some examples of elastomers are Butyl/Polyester and EPDM/Polyester. These materials are rated for temperatures up to 300oF, but a manufacturer’s recommendation for the type of elastomer used is essential. Moreover, the manufacturer should also prepare a thorough inspection and test plan based on codes and standards for the materials.
The most common cause of piping expansion joint failures is human error. These failures could have been avoided if the proper installation instructions were followed. These instructions, along with proper communication of the application requirements, could have prevented these disasters. For example, an application specification sheet should be available for piping expansion joints. Moreover, the Fluid Sealing Association maintains a wealth of information on the subject.
Material selection
There are many considerations when choosing the correct material for your rubber expansion joint. It is vital to choose the right material for your application and the temperature range in which it will operate. Some materials can handle temperatures as high as 250degF. Others, like nitrile rubber, can only stand 212degF. Stainless steel is also available, but it is best to check its temperature rating before using it.
In addition to temperature, pressure, and fluid, you should consider the materials used for your rubber expansion joint. Common materials used for these devices include EPDM, IIR, NBR, and PTFE. These types of joints can also differ in their inner tube diameter, which depends on the design conditions. Some rubber expansion joints feature a full face flange design. This type features a flange that is surrounded by rubber and fabric, and is a part of the joint’s body.
Design considerations
Design considerations for rubber expansion joints include material and type of reinforcement. Rubber expansion joints are made from natural or synthetic elastomers, and may have internal metallic reinforcements. On the other hand, metal expansion joints are composed of thin gauge material and designed to absorb mechanical movements. Metal expansion joints are generally made from stainless steel. While rubber expansion joints offer a limited temperature range, metal expansion joints can withstand temperatures up to 1800 degrees Fahrenheit. Moreover, metal expansion joints have a lower working pressure at elevated temperatures than their rubber counterparts.
A good expansion joint should have a bellows. A bellows should have enough strength to handle pressure and be flexible enough to absorb deflections. In addition, the bellows should have minimal resistance and withstand repetitive loads. These are unique design challenges that designers must consider.
Application
The power generation industry is a large user of rubber expansion joints. This rubber expansion joint industry includes hydroelectric, nuclear and coal burning power plants. These types of facilities use several types of fluid pipe systems and have a high demand for rubber expansion joints. They can be found in both flange rings and bellows varieties.
The body of an expansion joint consists of fabric, interior metal reinforcement, and a rubber tube. It provides protection from wear, movement, and pressure. In addition, a tube made of solid rings or wire is embedded into the carcass, providing strength and durability. The expansion joint also has a leak-proof lining tube that extends from the bore to the outer edges of flanges.