ISO 16770:2019 specifies the Full-Notch Creep Test (FNCT) used to evaluate environmental stress cracking (ESC) resistance of polyethylene (PE) under a defined chemical environment and temperature.
It is commonly used when qualifying PE materials and PE products (such as pipe-related components or containers) where long-term cracking in the presence of surfactants or chemicals is a concern. If you need help confirming whether FNCT is the right ESC approach for your material or product form, talk with our team.
ISO 16770:2019 Plastics — Determination of environmental stress cracking (ESC) of polyethylene — Full-notch creep test (FNCT)
ISO 16770 is an International Standard that defines a practical, constant-load cracking resistance test for polyethylene in a controlled environment. The primary reported outcome is time to failure under the specified conditions.
Quick definition
What it is: A constant tensile load is applied to a notched PE specimen while it is immersed in a defined test environment at a specified temperature.
What it measures: Environmental stress cracking resistance, typically expressed as time to failure under the defined conditions.
Common name: Full-notch creep test (FNCT).
What this standard covers
ISO 16770 describes how to run an ESC resistance test on notched test specimens prepared from moulded sheets/specimens or taken from finished PE products. During the test, the specimen is held under a static tensile load while immersed in a defined environment (commonly a surfactant solution) maintained at a specified temperature, and the time to failure is recorded.
The method is developed for polyethylene materials and can also be used to evaluate PE products such as pipes, fusion welds/fittings, and blow-moulded PE containers, where aggressive environments can accelerate cracking.
Why this standard matters in testing
Environmental stress cracking can be a key limiting failure mode for polyethylene in service, especially when a component experiences sustained stress and chemical exposure. ISO 16770 provides a repeatable way to compare materials, compounds, and product forms under controlled conditions that are designed to promote ESC.
For many buyers, FNCT results support material selection, product validation, and change control (resin changes, processing changes, weld/fitting changes) when chemical exposure is part of the risk profile.
Common materials, product types, or applications covered
ISO 16770 is primarily used for polyethylene (PE) materials and can be applied to specimens prepared from finished products when ESC performance of the manufactured form matters.
Common examples: PE materials for processing, PE pipes, PE fusion welds/fittings, and blow-moulded PE containers.
Practical caution: When specimens are machined from extruded or moulded parts, ESC performance can be influenced by processing-induced orientation and residual stresses, not only the base material.
Common test or verification workflow
FNCT is typically run as a comparative ESC screening or qualification test, where the test conditions are fixed and materials or product forms are ranked by time to failure.
Common workflow: (1) prepare notched specimens from moulded plaques/specimens or finished parts, (2) apply a defined static tensile load, (3) immerse specimens in the specified environment held at the specified temperature, (4) monitor and record time to failure, and (5) report results in the format required by the citing specification or customer requirement.
Equipment commonly used for this standard
Because ISO 16770 is a constant-load, time-to-failure test performed in a controlled environment, equipment selection is driven by load stability, bath/environment control, and specimen preparation quality.
Common equipment: Constant-load tensile creep frames or a universal testing system configured to hold a stable static tensile load over long durations; temperature-controlled immersion bath compatible with the specified test medium; specimen fixtures/grips suitable for notched PE specimens; specimen machining and notching tools; monitoring/timing and data recording for failure events.
Quoting tip: The required load range, number of simultaneous stations, bath volume, and chemical compatibility are usually the largest drivers of system configuration.
How to read this designation or revision
Standard number: ISO 16770 identifies the FNCT method for evaluating ESC of polyethylene.
Edition/year: ISO 16770:2019 is the current published edition (Edition 2). An older edition, ISO 16770:2004, has been withdrawn and is replaced by the 2019 edition.
Revision sensitivity: Test conditions and reporting expectations can vary by edition and by the product/material specification that cites ISO 16770, so purchasing and test setup should reference the exact cited year.
Related standards, methods, or frameworks
ISO 16770 is commonly referenced alongside polyethylene material and product specifications that set ESC performance requirements. When you are testing finished products (for example, pipe sections or moulded parts), alignment between the cited ISO 16770 edition and the calling specification is critical for meaningful comparisons.
Request a quote for FNCT / ISO 16770 testing equipment
If you are planning FNCT capability and want to compare load capacity, number of stations, bath size, and temperature/environment control options, you can request a detailed quote for an ISO 16770-oriented setup matched to your throughput and specimen types.