Expansion joints are maintenance-free. They can only be tested if the expansion joint is supplied with 2-ply testable bellows using vacuum or air pressure testing.
![Number6](https://usbellows.com/wp-content/uploads/1990/07/number6-300x139.jpg)
Expansion joints are maintenance-free. They can only be tested if the expansion joint is supplied with 2-ply testable bellows using vacuum or air pressure testing.