Everything You Need to Know About SAE and ISO Standards for Hydraulic Oil Hoses

In high-pressure hydraulic systems, oil pipes are the core components for connecting and transmitting power. Choosing the wrong hydraulic oil pipe may cause leakage, bursting, or even serious equipment damage and personal injury. In order to regulate the design, performance and safety of hydraulic hoses, two main standard systems are used worldwide: SAE (Society of Automotive Engineers) standards and ISO (International Organization for Standardization) standards. Understanding the differences and applicable scenarios of these two systems is the key to ensuring the safe and efficient operation of the system.

1. What are SAE and ISO standards?
SAE standards originated in North America and are one of the most widely used hydraulic hose standards in the United States. They are based on specific design parameters, such as the number of structural layers, inner diameter size, minimum bend radius, temperature range, and working pressure level.
ISO standards have stronger international adaptability, especially among European, Asian and global equipment manufacturers. ISO standards not only cover similar performance indicators, but also place more emphasis on actual application performance testing, so they are gradually becoming the first choice in many new equipment designs.

2. Common SAE hydraulic oil pipe standards
The standard code of SAE hydraulic hose usually starts with "SAE 100R" and is followed by a number to indicate the specific type and purpose. For example:
SAE 100R1 is a medium-pressure hydraulic hose with a single-layer steel wire braid structure, suitable for general hydraulic transmission systems;
SAE 100R2 uses a double-layer steel wire braid, which can withstand higher pressures and is widely used in industrial equipment and construction machinery;
SAE 100R12 is a high-pressure application with a four-layer spiral steel wire structure, especially suitable for heavy-duty machinery or mining equipment;
SAE 100R16 and R17 are more compact oil pipe designs with a smaller bending radius, suitable for installation environments with limited space.

These standards clearly specify the inner pipe material, number of steel wire layers, outer layer material, wear resistance, etc., so that users can choose the right oil pipe according to the equipment requirements.

3. Overview of ISO hydraulic oil pipe standards
Compared with SAE, the ISO standard system pays more attention to the performance of products in actual operating environments and incorporates more flexibility in different grades. For example:
ISO 1436 is a standard corresponding to SAE 100R1 and R2, which specifies high-pressure hoses with wire braided structures;
ISO 11237 covers more flexible and compact hydraulic oil pipes suitable for modern industrial automation equipment;
ISO 18752 is a standard that has become increasingly popular in recent years. It replaces the traditional structural definition method with a performance grading system, allowing users to only focus on the required working pressure level and temperature range, making the selection more intuitive.

4. The core difference between SAE and ISO standards
The core difference between these two standard systems is reflected in several aspects:
The SAE standard is based on structure, that is, each type of oil pipe must use specified materials and structural layers, such as how many layers of steel wire, what kind of inner and outer layers of glue, etc. This method is very convenient when maintaining and replacing old equipment, especially in the North American market.
The ISO standard tends to be more "performance-oriented". For example, the ISO 18752 standard does not strictly require the use of a certain structure, but is based on whether the hose can pass the test under certain pressure and temperature conditions. This gives manufacturers more design freedom and simplifies the selection process for end users.
The ISO system contains more detailed grades and classifications, which can meet more special application scenarios.

5. Why ISO 18752 is becoming more and more popular
The reason why ISO 18752 is gradually replacing some SAE standards worldwide is mainly because it is more in line with the trend of modern industrial globalization.
ISO 18752 divides hoses into multiple "performance grades" according to working pressure and temperature. For example, a hose may be classified as "Grade D", indicating that it can withstand the highest pressure and remain stable under extreme temperatures. This classification method is very intuitive and convenient for engineers to quickly select models when designing systems.
At the same time, it also helps international equipment manufacturers standardize the supply chain, without having to prepare products with different standards for different markets, greatly reducing costs and improving delivery efficiency.

6. Should I choose SAE or ISO standards?
When choosing a hydraulic oil pipe standard, you should judge according to the actual situation:
If you are maintaining or replacing a US-made equipment that has been used for many years, and the original manual clearly stipulates a certain SAE standard model, then it will be safer and more compatible to continue using the SAE standard.
But if you are designing a new equipment from scratch, or you sell products to the international market, ISO standards will be more flexible and conducive to global unified procurement, especially ISO 18752, which can greatly reduce selection errors and system compatibility issues.

7. Final suggestions to ensure safety and compliance
No matter which standard is used, always follow the following points when purchasing and using hydraulic oil pipes:
Check the product technical manual to confirm its actual working pressure, temperature and fluid compatibility;
Check the condition of the hose regularly to pay attention to whether it is worn, aged, expanded or leaked;
Avoid mismatching of joints and pipe diameters, and ensure that all connections are tightened and leak-free;
Choose a reputable supplier or brand, especially when using it in high-pressure or hazardous environments.