ISO 9967:2016 specifies a method for determining the creep ratio of thermoplastics pipes with a circular cross-section. It is commonly used to evaluate time-dependent deformation under a sustained compressive load as part of product verification and performance assessment for plastic piping.
If you need help confirming whether creep ratio testing is the right fit for your pipe type, temperature conditions, or acceptance criteria, talk with our team about your standard-driven workflow.
ISO 9967:2016 — Thermoplastics pipes — Determination of creep ratio
ISO 9967 is a test method focused on creep behavior in plastic pipes. Rather than measuring short-term stiffness only, it tracks how pipe deflection develops over time when a constant compressive force is maintained.
The output is a creep ratio derived from deflection measurements taken over the defined test period and at the specified conditions referenced by the standard.
Quick definition
Document type: Test method (method for determining creep ratio).
What it measures: Time-dependent change in pipe deflection under sustained compressive loading, expressed as a creep ratio.
Typical use: Comparing material/formulation behavior, validating product designs, and supporting long-term performance discussions for thermoplastics piping.
What this standard covers
ISO 9967 provides a method to determine creep ratio for thermoplastics pipes with a circular cross-section. The standard centers on applying a constant compressive force to a pipe specimen and tracking deflection as a function of time.
It does not serve as a complete product specification by itself; users typically apply it within a broader qualification or quality program where the cited conditions and any acceptance limits are defined by the purchaser, manufacturer, or a related product standard.
Why this standard matters in testing
Thermoplastics can exhibit viscoelastic deformation under sustained load. Creep ratio testing helps quantify how much additional deflection develops over time compared with an earlier point in the test, supporting decisions on material selection, pipe design, and long-duration performance expectations.
From a lab and QA/QC perspective, the main practical value is repeatable, controlled loading and consistent deflection measurement over an extended period, so results are comparable across production lots, suppliers, or designs.
Common materials, product types, or applications covered
ISO 9967 applies to thermoplastics pipes with a circular cross-section. It is most relevant where sustained external loading or long-term dimensional stability is a concern.
Common examples: Plastic piping products evaluated for long-term deflection behavior, including pipes intended for buried, supported, or otherwise constrained service where load can be applied over time.
Common test or verification workflow
A typical ISO 9967 workflow is built around controlled compression and time-based deflection readings.
Common workflow elements:
- Prepare a pipe specimen of the required length and verify basic dimensions needed for setup.
- Condition the specimen and test environment as required for the referenced conditions.
- Apply a constant compressive force to the pipe using a defined loading arrangement.
- Measure deflection at defined time intervals over the specified duration.
- Calculate creep ratio from the recorded deflection data and report results in the format required by the cited edition and any contractual requirements.
Equipment commonly used for this standard
ISO 9967 is equipment-oriented in the sense that the test depends on stable, long-duration force application and reliable deflection measurement. The exact configuration should match the cited edition and the pipe size range being tested.
Common equipment families:
- Compression loading system: A test frame or creep test stand capable of maintaining a constant compressive force for the required duration.
- Loading fixtures: Parallel plate or equivalent compression platens/fixtures designed to load the pipe consistently and repeatably.
- Deflection measurement: Dial indicators, LVDTs, or other displacement sensors with suitable range/resolution, mounted to measure pipe deflection consistently over time.
- Environmental control (when required): Temperature-controlled chamber/room or localized conditioning to maintain the specified test conditions.
- Timing and recording: Data acquisition or logging suitable for scheduled readings and traceable records.
If you are comparing load capacity, fixture approach, sensor mounting, or temperature-control options for ISO 9967 testing, you can request a detailed quote for a configuration matched to your pipe sizes and reporting needs.
How to read this designation or revision
ISO 9967 is the standard number, and the year suffix (for example, :2016) identifies the published edition year being cited.
Because creep testing is time-based and sensitive to conditions, labs should ensure the purchase order, test report, and internal work instructions all reference the same cited edition and any specified test conditions (such as load level, duration, and temperature) required by that edition or by the controlling specification.
Related standards, methods, or frameworks when useful
ISO 9967 creep ratio testing is often used alongside other pipe property evaluations (for example, stiffness/deflection characterization and long-term performance verification) within a broader qualification or quality plan.
When a product specification or project requirement cites ISO 9967, it may also define additional mechanical, dimensional, or durability tests that work together to support fitness-for-use decisions.
Get help selecting an ISO 9967 test setup
If you want help matching a compression/deflection measurement setup to the exact ISO 9967 edition you must follow and the pipe size range you test, contact our team to discuss your application and lab constraints.