A hydraulic hose is a key component of a hydraulic system. Qualified hydraulic hoses can ensure the safety, reliability and interchangeability of the hydraulic system. This article will help you learn more about hydraulic hoses and the common standards, hopefully helping you to quickly understand and choose them.
What is the Standard of Hydraulic Hose
Hydraulic hoses are used to transfer hydraulic fluid to keep machinery running efficiently. It is subjected to pressures over 3,000 psi during its use, so it is important to ensure that hydraulic hoses are safe and reliable for your safety. Standards for hydraulic hoses are created to ensure the performance, safety and compatibility of hydraulic hoses. It mainly stipulates the material specifications, hose structure, performance requirements, testing procedures, labelling methods and quality control of hydraulic hoses.
Common Hydraulic Hose Standards
ISO Standards
ISO Standards are international standards that are more convenient for you to use in international procurement and multinational engineering projects. It categorises hydraulic hoses into steel wire braid reinforced hoses, steel wire wound reinforced hoses, thermoplastic reinforced hoses and performance rated hoses.
Performance Requirements
ISO specifies the maximum working pressure and burst pressure corresponding to different hose models. The maximum working pressure of a hydraulic hose is the pressure below which you can use it normally. Burst pressure is the maximum pressure value of a hydraulic hose before it explodes. It also requires a temperature range for hydraulic hoses. With the hose in this temperature range, you will be able to run it properly. In addition, hydraulic hoses often need to be bent when in use, so ISO specifies the minimum bending radius of the hose to ensure its durability.
Test Procedure
ISO requires hydraulic hoses to pass pressure resistance tests, burst pressure tests, impulse fatigue tests, cold bend tests, ozone, oil and abrasion resistance tests and fluid compatibility tests. This ensures you can use hydraulic hoses properly in most environments.
- Pressure Resistance Test: Tests the pressure resistance by subjecting the hose to a pressure higher than the maximum working pressure for a specified period of time.
- Burst test: Determines the maximum pressure a hydraulic hose can withstand before exploding using a burst test.
- Cold Bend Test: Tests the ability of a hydraulic hose to withstand temperature fluctuations by alternately using the hose at high and low temperatures.
- Impulse fatigue test: Repeatedly bending a hose to assess whether it can withstand high-frequency bending.
- Abrasion Test: Repeated abrasion of a hydraulic hose to assess its durability.
- Fluid compatibility test: Using a hydraulic hose to transport different hydraulic fluids, evaluate its performance with different hydraulic fluids and rule out the influence of the type of hydraulic fluid on its effectiveness.
Marking
ISO requires hoses to be printed with the manufacturer’s logo, hose number, inside diameter, maximum working pressure, date of manufacture or batch number and flow direction. This ensures that you can choose a hydraulic hose that is more suitable for your application.
ISO Standard Hose Types
- ISO 1436: Standard for classification according to conventional construction. Specifically for steel wire braid reinforced rubber hoses. Hydraulic hoses consist of an inner rubber layer, one or two layers of steel wire braid and an outer rubber layer. It has medium bending properties, a consistent outside diameter and good compatibility with a wide range of fluids. With a wide range of applications, you can use them in medium-pressure hydraulic hose systems.
- ISO 3862: For steel wire-wound reinforced rubber hoses, consisting of an inner rubber layer, four to six layers of steel wire spiral-wound and an outer rubber layer. You can use it in high-pressure or even ultra-high-pressure systems and harsh environments. It is highly impact resistant and supports working pressures of up to 6,000 psi:
- ISO 11237: Compact steel wire braided hose, similar to ISO 1436, but it is lighter. Ideal for you to use in tight spaces and light hydraulic systems.
- ISO 3949: thermoplastic reinforced hydraulic hose, consisting of a thermoplastic inner layer, a synthetic fibre or plastic reinforcement and an outer layer. It is very resistant to corrosion and you can even use it for chemical fluid transfer. It is lightweight and you can use it in hand-held tools and portable equipment.
- ISO 18752: does not differentiate between hoses by braiding, winding or thermoplastics, and classifies hydraulic hoses into four classes, A, B, C, D, according to their performance. D grade is the highest grade. At the same time, each class is categorised according to pressure, mainly including 100, 160, 210, 280, 350, 420 bar, which you can use in modern engineering projects, facilitate the unification of product lines and simplify inventory management.
SAE Standards
SAE standards were developed by SAE International and are widely used in North America. You can apply it in various hydraulic systems such as automobiles, excavators, trucks and agricultural machinery. It sets standards for hydraulic hose size, structure, pressure rating, temperature applicability range, chemical resistance, abrasion resistance, ozone resistance, test methods and qualification standards, and hose marking methods.
Size Requirements
The inside diameter affects hydraulic flow and system pressure drop; too small increases resistance, while too large affects pressure maintenance, so SAE standards specify different inside diameters and tolerances for hoses based on specific specifications. The outside diameter of a hose affects the space available for the hose’s alignment, and SAE specifies maximum values for the outside diameter. In addition, SAE specifies the minimum bending radius of a hose under pressure, which can effectively prevent hose breakage.
Performance Requirements
- Maximum Working Pressure: Depending on the type of hose, SAE has established a maximum working pressure standard that requires hydraulic hoses to be used for extended periods of time below the maximum working pressure.
- Minimum Burst Pressure: The minimum burst pressure ensures there is a safety redundancy factor in the hydraulic hose to prevent rupture due to transient pressure shocks, and SAE specifies the minimum burst pressure needs to be equal to or greater than four times the maximum working pressure.
- Pulse Life: Hydraulic hoses are required to meet a standard number of pulse cycles at specific pressures and temperatures. Test hydraulic hoses for the effects of pressure fluctuations caused by valves opening and closing in the hydraulic system, and load changes.
- Temperature range: SAE specifies that hydraulic hoses need to remain flexible at certain values of low temperatures and work at high temperatures for long periods of time without failing.
- Chemical resistance: To prevent the hydraulic hose from chemical corrosion caused by cracking and leakage, SAE requires the hydraulic hose outer rubber layer needs to be ozone-resistant, ultraviolet-resistant. And the inner rubber layer needs to be resistant to hydraulic oil, fuel, coolant and other chemicals.
Test Standard
SAE requires the experimental conditions and judgment criteria.
- Leakage test: Hydraulic hose needs to be kept at working pressure for a certain period of time without liquid seepage.
- Burst test: The test process needs to be equipped with fittings at both ends of the hose, and continuous pressure until the burst. Burst pressure must be higher than the specified value, and the rupture location needs to be in the body of the tube. The joints can not leak or fall off.
- Pulse Fatigue Test: The test requires cyclic application of high and low pressures for a period of 200,000 to one million cycles. Pressure values vary depending on the hose size. The hose must not leak, bulge or burst during this process.
- Abrasion test: The outer layer is rubbed with an abrasion tool to determine the abrasion life of the hydraulic hose.
- Ozone/UV Resistance Test: Depending on the specifications of the hydraulic hose, the hose is exposed to a certain concentration of ozone and temperature for a certain period of time, and finally confirms whether there are any cracks on the surface of the hose.
- Low temperature bending test: To ensure the hydraulic hose can be used normally in cold conditions. It is necessary to bend the hose under the condition of minus 40 degrees for a certain radius, and finally check whether there is any crack on the surface of the hose.
Marking Requirements
SAE standards require that hydraulic hoses be permanently marked on the outer rubber layer. The marking may be printed or embossed, but must be continuous and legible so that it does not easily wear off. The marking should include the number, size, manufacturer’s code, date of manufacture or batch number, maximum working pressure, place of manufacture, temperature and application.
SAE Standard Hose Types
- SAE 100R1/R2: Braided hose with single or double braid reinforcement for durability and flexibility.SAE 100R1 is a single braid that you can use for medium-pressure work, such as portable small mobile hydraulics.SAE 100R2 is a higher-pressure hose that you can use for agricultural machinery.
- SAE 100R7/R8: The thermoplastic hose is lightweight and chemically resistant, making it suitable for hydraulics in tight space configurations.SAE 100R7 is available in nylon or polyurethane reinforcement, which you can use in medium-pressure hydraulics.SAE 100R8 is a high-pressure grade of thermoplastic hose that is also corrosion-resistant.SAE 100R12/R13 is a high-pressure grade of thermoplastic hose that is also corrosion-resistant.
- SAE 100R12/R13: spiral steel wire reinforced hose is suitable for ultra-high-pressure hydraulic systems with high resistance to pulsation.SAE 100R12 has four layers of steel wire spiral and has a working pressure of about 4,000 psi.SAE 100R13 has four or six layers of steel wire spiral and has a longer life of pulsation cycle and can withstand ultra-high-pressure hydraulic systems.
EN Standards
EN standards are developed by the European Committee for Standardisation (CEN) and apply to industrial product standards in Europe. In order to facilitate the unified management of the European Union, most EN standards are equivalent to ISO standards, but EN is more stringent.
Construction Requirements
EN regulates standards for the construction of hydraulic hoses, including the material, thickness and hardness of the inner rubber layer, the structure and number of layers of steel wire braid, winding and fibre layers of the reinforcing layer, and the type of material and anti-abrasion rating of the outer rubber layer.
Size Requirements
EN has ranges for both ID and OD and strictly controls overall tolerances and dimensions. The ID controls the amount of flow through the hose, while the OD affects the size of the hydraulic hose. EN standard strictly limits the ratio of inner rubber, steel wire and outer rubber layers. In addition it sets standards for bending radii, assessing the minimum bending capacity of a hydraulic hose before it is damaged.
Performance Requirements
EN mainly specifies the maximum working pressure, the minimum burst pressure, the number of pulse cycles and the operating temperature range as well as the chemical resistance of hydraulic hoses. Of these, the maximum working pressure determines the type of hydraulic system you can use the hose in. Minimum burst pressure is the ultimate pressure a hose can withstand before it is destroyed. Pulse life mainly refers to the number of cycles of a hydraulic hose under 50-degree oil conditions. Chemical resistance primarily includes the ability to withstand mineral oils, fuels, hydraulic fluids and ozone.
Test&Marking Standard
The EN test standards also include leakage tests, abrasion tests, burst tests, impulse fatigue tests, low-temperature bending tests, ozone tests, etc. The EN standards also require that hydraulic hoses must have a standardised number, an internal diameter, manufacturer’s information, a maximum working pressure, and a date of manufacture or batch number.
Examples of EN Standard Hose Types
- EN 853 1SN/2SN: The single steel wire braided rubber hose (EN 853 1SN) has a steel wire braid and is able to withstand medium working pressures of approx. 88 to 250 bar. It is suitable for small and medium-sized hydraulic equipment, agricultural machinery. The double steel wire braided rubber hose (EN 853 2SN) has two layers of steel wire braid and can withstand medium to high working pressures from approx. 160 to 400 bar, so you can use it in construction machinery.
- EN 854 1TE/2TE/3TE: Fibre-reinforced hose, reinforced with a fibre wire braid. It is flexible, lightweight and resistant to bending, so you can use it in low-pressure hydraulic systems.
- EN 857 1SC/2SC: Compact steel wire braided hose with a small bending radius and good flexibility. You can best use it in narrow hydraulic lines and in dense hose laying areas.
- EN 856 4SH: Ultra-high-pressure, four-ply steel wire-braided hose can withstand ultra-high pressures up to 500+, and has a high burst pressure and is very durable. You can even use it in extreme environments.
- EN 855 R6: Thermoplastic fibre-reinforced hose is more resistant to corrosion and oil and has a lower working pressure, making it suitable for light hydraulic tools.
Differences between ISO, SAE and EN Standards
ISO, SAE and EN Standards are common standards for hydraulic hoses. All three define the construction and materials, dimensional tolerances, performance classes, test methods and qualification criteria, and labelling requirements for hydraulic hoses. The main difference lies in the application scenario and the standard requirements for hydraulic hoses are not identical.
Differences in usage scenarios
ISO standards are globally interoperable and specify those standards for a wide range of types and industry scenarios.SAE is mainly centred on construction machinery and automotive hydraulics and is more suitable for your use in the North American market. Whereas EN is mainly applicable to Europe and countries and regions that have adopted EU standards.
Differences in standard requirements
The requirements of ISO, SAE and EN Standards are not identical. For example, EN mandates abrasion, ozone and low-temperature bending tests, whereas ISO and SAE only require these tests for some hydraulic hoses. ISO and SAE only require some hydraulic hoses to undergo these tests, while SAE is very demanding in terms of oil and pressure resistance, and ISO is more inclusive due to its global standardisation.
Why Hydraulic Hose Standards Matter
Improve Quality
The standards for hydraulic hoses strictly require the hose to pass a series of quality tests. This ensures the hose is capable of transmitting different fluids for use at different pressures and in different environments. This improves the quality of the hydraulic hose you buy.
Improve Security
Hydraulic hose standards strictly require that the outer rubber layer must be clearly marked with the use of performance and use of the scene and so on. So you can choose the right hose according to your work needs.In addition, the requirement for hydraulic hoses to pass a series of tests helps to minimise the risk of failure during operation, increasing safety.
Expanded compatibility
Different manufacturers produce different models of components. The strict harmonisation of standards makes it possible to equip yourself with components from different manufacturers. This extends the compatibility of hydraulic hoses produced by different manufacturers. It makes it easier to replace and repair.
Facilitates Monitoring and Record-keeping
The Hydraulic Hose Standard provides the industry standard for measuring the quality of hydraulic hose. Regulators can more easily ensure that products meet performance and are safe. Labelling requirements also facilitate quality traceability and accountability.
Easy Shopping
Even though different manufacturers make different hydraulic hoses, they all meet the same standards. By choosing a hose that meets or exceeds these standards, you can improve the overall performance and longevity of your equipment.
Conclusion
This article explains in detail what hydraulic hose standards are and details three commonly used standards. Hopefully, understanding this will help you to understand and buy quickly. Target Hydraulics offers different types of hydraulic hoses. They can perfectly fit your various equipment and also be safe, reliable and durable. Please feel free to contact us for more information.
