Information on the most widely used ASTM standards within the materials testing industry
ISO 4599:1986 Plastics — Determination of resistance to environmental stress cracking (ESC) — Bent strip method
ISO 4599 standard evaluates the crack resistance of plastic materials under specific environmental conditions through constant pre-strain tests. This performance testing is crucial for assessing the durability and reliability of plastic materials in practical applications.
(ISO 4599 has been withdrawn and replaced by ISO 22088-3:2006 (Plastics - Determination of resistance to environmental stress cracking (ESC) - Part 3: Bent strip method)

Scope and Applications
This standard is applicable for measuring the resistance of sheet and plate samples to environmental stress cracking, particularly the sensitivity of localized surface areas of the samples to ESCR. For sensitivity measurement of finished products or large materials under constant strain, it is recommended to refer to ISO 4600. The bending strip method is used to determine ESC caused by gases and liquids and by solids containing migrating substances, such as polymer adhesives and materials containing plasticizers.
Testing Methods and Steps:
1. Sample Preparation: Prepare sheet and plate samples that comply with the standard.
2. Pre-strain: Subject the samples to a pre-strain treatment under specific environmental conditions.
3. Observation and Recording: After a certain period of pre-strain, observe and record the changes in the samples, especially the cracking conditions in localized surface areas.
4. Result Analysis: Assess the environmental stress cracking performance of the samples based on their changes.
Through these steps, the crack resistance of plastic materials under specific environmental conditions can be effectively measured, thereby assisting in the selection of suitable materials for different application scenarios.
Importance of ISO 4599 Tests for Materials
Performance Prediction
ESC resistance is critical for plastics used in environments where they encounter both chemicals and mechanical stress (e.g., pipes, containers, cable jackets). ISO 4599 provides a standardized method to predict material durability under these conditions.
Safety Assurance
Premature failure due to environmental stress cracking can have severe consequences, especially in critical applications like chemical storage, medical devices, and electrical insulation. ISO 4599 helps ensure materials meet safety requirements.
Quality Control
The test enables manufacturers to maintain consistent product quality by verifying that each batch meets ESC resistance specifications.
Material Development
Researchers use ISO 4599 to develop new materials with improved ESC resistance by evaluating the effect of additives (e.g., antioxidants, UV stabilizers) and processing parameters.
Regulatory Compliance
Many industry specifications for plastic products (e.g., ISO 4427 for polyethylene pipes) reference ESC test methods like ISO 4599 to ensure compliance with international safety and performance standards.
Cost Reduction
By identifying materials with inadequate ESC resistance early in the development cycle, manufacturers avoid costly product failures, recalls, and liability issues.
Related products and device
Related Standard
ISO 22088-3:2006 Plastics -- Determination of resistance to environmental stress cracking (ESC) Part 3: Bent strip method
ISO 22088-3 specifies a method for the determination of the environmental stress cracking (ESC) resistance of thermoplastics when they are subjected to a fixed flexural strain in the presence of chemical agents.
ESC is indicated by the change of a suitably chosen indicative property of specimens that have been strained for a defined time in the environment. The method of test is suitable for determining the resistance of sheets and of flat test specimens, especially the sensitivity of localized surface regions of specimens, to ESC.
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