Expansion Joint Customization: Options & Capabilities

Expansion joints are typically customized to solve one of three problems: misalignment from foundation settling that puts a standard joint under constant stress, piping sections with non-standard internal diameters or flange drilling patterns, and fabric duct/exhaust applications that require frame-mounted designs instead of standard configurations. Kadant Unaflex has engineered custom solutions for each of these cases for over 40 years. Here's what can actually be customized and why it matters.

Expansion joint customization typically falls into three categories: offset or angular configurations to correct misalignment from foundation settling, non-standard dimensions or flange drilling to match existing piping, and frame-mounted fabric joint designs (J-frame or A-frame) for high-temperature, low-pressure duct and exhaust applications.

Correcting Misalignment

Misalignments are a primary reason for customized configurations. Misalignments are often the result of foundation settling in older facilities causing unnecessary stress on a standard expansion joint. A standard, straight-line configuration could be positioned to create the proper connection between the pipe segments. This forcing of the joint never allows the joint to return to its resting position. Kadant Unaflex can create the offset needed that allows the joint to properly rest when thermal and mechanical forces are not acting upon the system.

Non-Standard Dimensions and Flange Drilling

Customization does always have to be the result of alignment issues. In some cases, a section of piping may have different internal diameters or different flange drilling patterns all of these can be achieved with custom joints.

Customizing Fabric Expansion Joints

Customization of joints is standard in the fabric expansion joint line. The Thermaflex line of products is specifically designed for this type of application. Fabric expansion joints typically consist of a metal frame that attaches to the mating flanges while also connects the belt across the void. The frames may include a stand-off such a “J” frame or without as in a “A” frame design. Fabric expansion joints are primarily for use in high temperature, low pressure applications such as ducting and exhaust.

A-FrameJ-Frame