ISO 899-1:2017

Overview

ISO 899-1:2017 - Plastics - Determination of creep behaviour - Part 1: Tensile creep specifies a standardized laboratory method for measuring the tensile creep of plastics using dumb‑bell test specimens. The standard covers specimen preparation, conditioning (temperature and humidity), mounting, loading, extension measurement and result presentation. It is intended to generate reliable creep data for engineering‑design, research and quality‑control purposes and includes guidance on factors that strongly influence creep behaviour (for example thermal history and conditioning).

Key topics and technical requirements

• Scope of test specimens: rigid and semi‑rigid, non‑reinforced, filled or fibre‑reinforced plastics formed as dumb‑bell specimens (moulded or machined).
• Conditioning and atmosphere: condition specimens per the material standard or ISO 291. Effects of humidity and thermal history are emphasized; recommended conditioning time references ISO 62.
• Loading and control: loading system must apply load smoothly and maintain it within ±1%. Preload and loading procedures are defined for repeatability.
• Extension measurement: engineering‑design data requires use of extensometers to measure gauge‑length strain; research/quality‑control may use nominal extension (grip separation). Extension devices must not influence specimen behaviour; accuracy of extension measurement should be better than ±0.01 mm. Contactless optical systems are recommended for creep‑to‑rupture tests.
• Time and temperature control: time measurement accuracy to 0.1%; temperature variation during a test should remain within ±2 °C.
• Results and reporting: calculation and presentation of tensile‑creep modulus (Et), nominal tensile‑creep modulus (E*t), creep curves, creep‑modulus/time curves, isochronous stress‑strain curves, creep‑to‑rupture curves and precision statements. Annex A discusses physical‑ageing effects on polymer creep.

Practical applications

• Determining long‑term deformation under constant tensile load (creep) for component design, lifetime prediction and safety factors.
• Comparing materials (rigid, filled, fibre‑reinforced plastics) for selection in structural or load‑bearing applications.
• Quality control and R&D: validating processing, conditioning and ageing effects on creep performance.
• Generating data for finite‑element models and isochronous design curves used by engineers.

Who should use ISO 899-1:2017

• Materials engineers and R&D teams performing polymer mechanical characterization.
• Design engineers needing validated creep data for safety and durability assessments.
• Testing laboratories performing standardized tensile creep and creep‑to‑rupture testing.
• Quality managers monitoring batch consistency and the effects of processing or conditioning.

Related standards

• ISO 291 (conditioning atmospheres), ISO 472 (vocabulary), ISO 527‑1/‑2 (tensile properties), ISO 10350‑1 (thermal history/material data), ISO 62 (conditioning time).