Overview
ISO 28702:2008 is an international standard that specifies a test method for assessing the low-temperature brittleness of rubber and plastics hoses and tubing reinforced with textile materials. This standard focuses on the sub-ambient temperature crush test, which evaluates the ability of hoses with a nominal bore up to 100 mm to resist cracking or damage when subjected to compression at low temperatures. Developed by ISO Technical Committee ISO/TC 45, this standard is key for manufacturers and users seeking to ensure the durability and safety of textile-reinforced hoses in cold environments.
Key Topics
- Scope: Applies exclusively to textile-reinforced rubber and plastics hoses and tubing with nominal bores up to 100 mm.
- Test Principle: A ring test piece of the hose is compressed to 50% of its inside diameter at specified sub-ambient temperatures, and then examined for cracks or other abnormalities.
- Test Temperatures: Includes several standardized sub-ambient temperature points:
- 0 °C ± 2 °C
- −10 °C ± 2 °C
- −25 °C ± 2 °C
- −40 °C ± 2 °C
- −55 °C ± 2 °C
- Test Procedure:
- Condition the hose test piece and compression jig in a chamber at the test temperature for 24 hours.
- Compress the test piece between two flat plates to 50% of its inside diameter within 5 seconds.
- Examine the test piece after warming to room temperature for cracks, fractures, or layer separation.
- Apparatus: Requires a compression jig or equivalent mechanical testing equipment and a temperature-controlled conditioning chamber.
- Reporting: Test results must include reference to ISO 28702:2008, hose type, nominal bore, test temperature, testing conditions, examination outcomes, and test date.
Applications
ISO 28702:2008 is essential for industries using textile-reinforced rubber and plastic hoses in environments where exposure to low temperatures can impair hose performance. Typical applications include:
- Automotive and transportation sectors requiring hoses that maintain integrity in cold climates.
- Industrial manufacturing where hoses transport fluids or gases at sub-ambient temperatures.
- Oil and gas pipelines utilizing textile-reinforced hoses exposed to harsh, cold environments.
- Chemical processing plants needing reliable tubing resistant to brittleness caused by low temperatures.
This standard helps manufacturers verify hose durability under cold conditions, ensuring safety, reliability, and compliance with regulatory requirements.
Related Standards
- ISO 23529: General procedures for preparing and conditioning rubber test pieces, referenced for conditioning methods.
- ISO 4672 (to be replaced by ISO 10619-2): Defines sub-ambient temperature flexibility tests for rubber and plastics hoses, complementing the crush test by evaluating hose flexibility.
- Other ISO standards under ISO/TC 45 related to rubber hose materials and test methods.
Summary
ISO 28702:2008 provides a standardized method to assess the brittleness of textile-reinforced rubber and plastics hoses at low temperatures. By ensuring hoses can withstand compression at sub-ambient temperatures without cracking, the standard supports the development and use of robust hoses suitable for demanding cold environment applications. Compliance with ISO 28702 aids in guaranteeing product quality, operational safety, and durability for hoses in sectors ranging from automotive to industrial and chemical processing.
Open preview (PDF)Rubber and plastics hoses and tubing — Textile-reinforced types — Sub-ambient temperature crush test