Plastics hoses and hose assemblies - Textile-reinforced types for hydraulic applications - Specification (ISO 3949:2018); German version EN ISO 3949:2018
1Key Takeaways
ISO 3949 specifies requirements for three types of textile-reinforced thermoplastics hose and hose assembly of nominal size from 3,2 to 25. Each type is divided into two classes dependent on electrical conductivity requirements. They are suitable for use with water-based hydraulic fluids HFC, HFAE, HFAS and HFB as defi…
2Expert Interpretation
An in-depth interpretation of the DIN EN ISO 3949:2018 standard covers the technical requirements, performance testing, and marking specifications for textile-reinforced thermoplastic hydraulic hoses. A detailed analysis of the differences between the R7, R8, and R18 models, including key parameters such as dimensional tolerances, burst pressure, and pulse testing, provides professional guidance for hose selection in hydraulic systems.
Standard Overview and Revision Background
DIN EN ISO 3949:2018 is the international standard for textile-reinforced thermoplastic hoses and hose assemblies for hydraulic systems, superseding the 2014 edition. This standard was jointly developed by Technical Committees ISO/TC 45, Rubber and rubber products, and CEN/TC 218, Rubber and plastic hoses and hose assemblies. The German version was published in November 2018.
Major Technical Changes
Compared to the 2009 edition, the 2018 edition of the standard has undergone significant technical revisions: requirements for hose type R8, nominal size 8, have been added to Tables 1, 3, 4, and 5; a reference to ISO 10619-1:2017, Method A1, has been added to Section 7.3; additional requirements for hose marking have been added to Section 10.1; and ISO 17165-1 has been referenced in Section 10.2.
| Revisions | 2009 Edition | 2018 Edition | Technical Significance |
|---|---|---|---|
| R8 Hose Specifications | Not Included | New Size 8 | Expanded High Pressure Application Range |
| Bend Test Method | Old Method | ISO 10619-1:2017 A1 | Improved test accuracy |
| Marking requirements | Basic requirements | Added detailed marking | Enhanced traceability |
Hose types and grade classification
The standard specifies three types of textile reinforced thermoplastic hoses with nominal sizes ranging from 3.2 to 25:
Type R7: Hose with one or more reinforcement layers, standard working pressure application
Type R8: Hose with one or more reinforcement layers, suitable for higher working pressure
Type R18: Reinforced layer hose based on 21.0 MPa working pressure
Each hose type is divided into two grades according to electrical characteristics: Class 1 no electrical requirements; Class 2 non-conductive type (meets the requirements of Clause 7.8).
Material and construction requirements
The hose must consist of a seamless thermoplastic inner layer resistant to hydraulic fluids, a suitable textile yarn reinforcement layer, and an outer layer resistant to hydraulic fluids, water and weather. The outer layer of Class 2 hoses must not have pinholes and the outer layer color must be orange (RAL 2004).
Dimensional and tolerance requirements
The hose diameter measured in accordance with ISO 4671 must comply with the values specified in Table 1:
| Nominal size (mm) | Minimum inside diameter (mm) | Maximum inside diameter (mm) | Outer diameter range (mm) |
|---|---|---|---|
| 3.2 | 3.4 | 4.0 | 9.5-10.5 | 5 | 4.6 | 5.4 | 11.4-14.6 |
| 6.3 | 6.2 | 7. 0 | 13.7-16.8 |
| 8 | 7.7 | 8.5 | 15.6-18.6 |
| 10 | 9.3 | 10.3 | 18.4-20.3 |
| 12.5 | 12.3 | 13.5 | 22.5-24.6 |
| 16 | 15.5 | 16.7 | 25.8-29.8 |
| 19 | 18.6 | 19.8 | 28.6-33.0 |
| 25 | 25.0 | 26.4 | 36.7-38.6 |
Performance Test Requirements
Pressure Performance Test
Tested in accordance with ISO 1402, hoses and hose assemblies shall not leak at the corresponding test pressure and minimum burst pressure.
| Nominal size (mm) | R7 type working pressure (MPa) | R8 type working pressure (MPa) | R18 type working pressure (MPa) |
|---|---|---|---|
| 3.2 | 21.0 | 42.0 | 21.0 |
| 5 | 21.0 | 35.0 | 21.0 |
| 6.3< /td> | 19.2 | 35.0 | 21.0 |
| 8 | 17.5 | 31.0 | < td>21.0|
| 10 | 15.7 | 28.0 | 21.0 |
| 12.5< /td> | 14.0 | 24.5 | 21.0 |
| 16 | 10.5 | 19.2 | 21.0 |
| 19 | 8.7 | 15.7 | 21.0 |
| 25 | 7.0 | 14.0 | 21.0 |
Impulse Test Requirements
Impulse testing must comply with ISO 6803, with a test fluid temperature of 93°C. R7 hose must withstand a minimum of 150,000 impulse cycles at an impulse pressure of 125% of the maximum working pressure; R8 and R18 hoses must withstand a minimum of 200,000 impulse cycles at an impulse pressure of 133% of the maximum working pressure.
Electrical Performance Requirements
Class 2 non-conductive hoses must pass the test in Appendix D and conduct no more than 50μA. The test is conducted using an unpressurized hose assembly with a free length of (150±10) mm. After conditioning for 168 hours at 85% relative humidity and (23±3)°C, an AC voltage of (37.5±0.5) kV is applied for 5 minutes and the current is measured.
Fluid Compatibility Requirements
The standard applies to: HH, HL, HM, HR, and HV oil-based hydraulic fluids as specified in ISO 6743-4, with a temperature range of -40°C to 93°C; HFC, HFAE, HFAS, and HFB water-based fluids as specified in ISO 6743-4, with a temperature range of 0°C to 60°C; and water at a temperature of 0°C to 60°C.
Note: It is the user's responsibility to consult with the hose manufacturer to ensure hose compatibility with the fluid being used.
Identification and Marking Requirements
Hoses must be marked with the following information, repeated at least every 760 mm: manufacturer's name or trademark; ISO 3949 standard number; type and class (e.g., R7-1); Class 2 hoses must be marked "NICHT LEITEND" (non-conductive); nominal size (e.g., 16); maximum working pressure (MPa and bar); the last two digits of the year of manufacture and the quarter (e.g., 2Q18).
Example: XXX/ISO 3949/R7-1/16/10.5 MPa (105 bar)/2Q18
Quality Control and Testing Frequency
The standard specifies three types of tests: type testing, batch testing, and manufacturing testing. Type testing is to be repeated every five years or when the manufacturing process or material is changed; batch testing is to be conducted before each roll of finished hose is delivered; and manufacturing testing is to be conducted for quality control at the frequency recommended in Appendix B.
Implementation Recommendations and Application Guide
When selecting a hydraulic hose, choose the appropriate type and grade based on the actual working pressure, fluid type, and environmental conditions. Type R7 is suitable for general pressure applications, Type R8 is suitable for higher pressure applications, and Type R18 is designed for a working pressure of 21.0 MPa. Class 2 non-conductive hoses are suitable for special environments requiring anti-static protection.
Users are advised to: confirm fluid compatibility with the manufacturer; regularly inspect the appearance of the hose; use it strictly in accordance with the marked working pressure; and replace the hose in a timely manner before its service life expires.
Standard Development Trends
As hydraulic technology develops towards high pressure and intelligence, future hose standards may further increase: new hoses with higher pressure grades; stricter environmental protection and recyclability requirements; integration requirements for intelligent monitoring functions; more accurate life prediction methods, etc.