How to Select the Correct Elastic Ductile Iron Joints

Choose the product according to the actual problem:

• ◆  For connecting two compatible plain-ended pipes, consider a dedicated Gibault joint or coupling.

• ◆  For replacing a valve or pump in a flanged line, consider a dismantling joint.

• ◆  For pump vibration or specified multidirectional movement, consider a rubber expansion joint.

• ◆  For pipes exposed to axial thrust, use a restrained joint or engineered anchoring system.

• ◆  For PE or thin-wall PVC pipe, confirm whether an internal support insert is required.

• ◆  For legacy pipes, measure the OD instead of relying only on the nominal size.

Material and Corrosion Protection Options

Depending on the joint type, project options may include:

• ◆  Ductile iron or cast iron components

• ◆  FBE, epoxy paint, bitumen or Rilsan coating

• ◆  EPDM, NBR or other specified gasket compounds

• ◆  Galvanized carbon-steel hardware

• ◆  SS304 or SS316 fasteners

• ◆  Dedicated or wide-tolerance OD ranges

• ◆  PN10, PN16 or other verified pressure classes

• ◆  Project-specific flange drilling

These options are not interchangeable across every joint. Final materials, pressure and dimensions must be confirmed for the selected product.

Application Areas

Flexible pipe joint solutions are commonly considered for:

• ◆  Municipal water distribution

• ◆  Wastewater pipelines

• ◆  Irrigation systems

• ◆  Pumping stations

• ◆  Valve chambers

• ◆  Water-treatment facilities

• ◆  Industrial cooling-water lines

• ◆  Pipeline rehabilitation and maintenance

Frequently Asked Questions

Are elastic ductile iron joints the same as rubber expansion joints?

No. “Elastic joint” is sometimes used loosely, but a ductile iron mechanical joint and a rubber expansion joint have different structures and functions. The required movement must be defined before selection.

Can a flexible joint replace a restrained joint?

Not automatically. A flexible joint may accommodate angularity but still allow axial pipe movement. A restrained product or external anchoring is required where pressure thrust can cause pullout.

Can flexible joints connect different pipe materials?

Some universal products can cover multiple materials and OD ranges, while dedicated Gibault joints are designed around specific pipe dimensions. Compatibility must be confirmed from the product table.

Which gasket should be selected?

The gasket depends on the medium, temperature and approval requirements. Provide the service conditions instead of choosing EPDM or NBR from the product name alone.

Request Flexible Joint Selection Support

Send your pipeline drawing, pipe OD, pressure and required type of movement. Solid can help determine whether the connection requires a Gibault joint, dismantling joint, rubber expansion joint or restrained solution.