Ring Stiffness Testing Machine

Measures ring stiffness and deformation performance of plastic pipes (PVC, PE, PP). High-precision force and deformation measurement with robust industrial design for production and QC labs. Available in nine configurations from 5 kN to 200 kN — compare the models below.

Proving buried pipe resists soil and traffic loads

Sewer and drainage pipe usually carries no internal pressure — its job is to survive burial without excessive deformation. Ring stiffness testing compresses a pipe sample between two parallel plates at a constant rate and records the force needed to reach a set deflection, then calculates a stiffness value independent of diameter. Alarge builds the machine in nine capacities from 5 kN to 200 kN, so a lab can test small drainage pipe and large-diameter corrugated or solid-wall pipe on a correctly sized frame, to ISO 9969 and ASTM D2412.

• Capacity range: 5 kN – 200 kN (9 configurations)
• Wide pipe diameter compatibility (PVC, PE, PP)
• High-precision force & deformation measurement
• Repeatable, stable test performance
• User-friendly interface
• Remote service support

Standards

• ISO 9969 — Thermoplastic pipes — ring stiffness
• ASTM D2412 — Ring deflection of thermoplastic pipe

Frequently Asked Questions

What is ring stiffness?

A pipe's resistance to diametral deflection under external load, calculated from the force at a specified deflection and the pipe dimensions. Pipes are classified by ring stiffness classes (SN) in kN/m².

How is the test performed?

A pipe section is compressed between two flat plates at a constant speed until the specified deflection (commonly 3% of the diameter) is reached; force and deflection are recorded throughout.

Which capacity do I need?

It depends on the largest diameter and stiffness class you test. Nine models from 5 kN to 200 kN are available — compare them in the model table on this page.

Which pipes are tested?

PVC, PE and PP pipes — especially corrugated and solid-wall sewer, drainage and cable-protection pipe for buried applications.

Mechanical Test Systems