Expansion Joints are a Crucial Component in Industrial Piping Systems
Expansion joints are vital to the integrity and efficiency of industrial piping systems.
Expansion joints are an important piping system component because it protects critical infrastructure by accommodating movement and reducing vibration that occurs in piping systems.
However, their effectiveness hinges on proper selection and installation. A failure in an expansion joint can lead to operational downtime, environmental hazards, and significant repair costs.
Expansion joints act as flexible connectors within piping systems, allowing for movement caused by thermal expansion, pressure fluctuations, and mechanical forces. By allowing this movement, they prevent structural damage and can mitigate vibration.
This article outlines essential considerations and best practices to help you select the right expansion joint, ensuring reliability and long-term performance. We will focus on the most common types of joints: Metal, rubber and fabric, each with its unique set of advantages and disadvantages.
Four Steps to Select the Right Expansion Joint
Step One: Gather the Right Information About Your Application
The most important step is to gather as much information about your application as you can.
This will be key to understanding what kind of expansion joint will work best.
Just remember the acronym STAMP:
- S: Size (Pipe Size)
- T: Temperature
- A: Application (Type of plant, media, corrosiveness, velocity, vibration)
- M: Movement & Overall Length of expansion joint
- P: Pressure
Step Two: Match Your Application Specs to the Right Type of Expansion Joint
Using the STAMP information you gathered from step one, you can match your application’s needs to the expansion joint best equipped to support it. Learning the advantages and disadvantages of each type of expansion joint will help you understand the limitations of each.
| STAMP Category |
Expansion Joint Material | ||
|---|---|---|---|
| Metal | Rubber | Fabric | |
| Size | |||
| Temperature | Cryogenic – High (1200+ F) |
Low (up to 300 F) | High (1200+ F) |
| Application Type | |||
| Movement / Flexibility | Good | Better | Best |
| Pressure | FV up to 1000+ psi | Low to medium (Vacuum up to 300 psi) | Low (+/- 5 psi) |
| Other Expansion Joint Characteristics to Consider | |||
| Leak Tight? |  |
|
|
| Cost | $$-$$$$ | $-$$ | $-$$ |
| Life of Expansion Joint | Best Some metal expansion joints can last 20+ yrs |
Good Generally Rubber expansion joints have a shorter life than metal and may need replaced every couple of years |
Good Fabric expansion joints will need replaced every couple of years but the metal frame can last a long time. |
| Maintenance | Minimal | Frequent (wear & tear) | Frequent (wear & tear) |
| Engineering Design & Standards | EJMA, ASME Codes (B31.3, B31.1, Section 8), EN | FSA | FSA |
Step Three: Selecting the Bellows Configuration
While the main function of an expansion joint is to absorb movement and/or vibration, there are several types of expansion joints that can also restrain the pressure thrust of the pipeline.
The movement, function of the expansion joint and pipe layout will help narrow down the choices of the right expansion joint for your application.
At this stage you can also specify Dimensions and End Fittings (i.e, Flanges, weld-ends, threaded ends.)
Step Four: Engage the Experts
After reading this guide you may find that you are in a “gray area” where one or more types of expansion joints can be used. We can help!
Our expert engineers can review your application’s specifications, conduct a pipe stress analysis, and provide insights to ensure the right expansion joint solution fits your piping system’s needs.
We’ve been designing and manufacturing engineered pipe expansion joints for the industry since the 1960s and we’ve been a proud member of the Expansion Joint Manufacturer’s Association (EJMA), since 2002 serving in both technical and management committees.
Conclusion
Selecting the appropriate metal expansion joint is not merely a technical requirement but a strategic investment in system longevity and safety. By following best practices, adhering to industry standards, and engaging with your engineering team here at US Bellows we can work together to choose the best expansion joint for your business needs. Do this can prevent costly downtime, protect personnel, and extend the life of your infrastructure. Expansion joints may seem like small components, but their role in maintaining operational continuity cannot be overstated.