Lesson 3 of 5 · Types
Hydraulic hose types and standards
Hose type codes such as 2SN, 4SP or R13 name a construction and a pressure class defined by a standard. A dozen codes cover almost every hose on a machine.
Two naming systems
Hydraulic hoses are named by the standard they are built to. There are two systems in everyday use. SAE J517 is the American system and uses codes beginning with 100R, such as 100R2. The European system uses the EN standards 853, 856 and 857, with codes such as 2SN and 4SP. ISO standards mirror both.
Many hoses are built to meet an SAE type and an EN type at the same time, and both codes are printed on the layline.
What the constructions look like
From lightest to heaviest: one wire braid, two wire braids, four wire spirals, six wire spirals. More wire means more pressure, more weight and a larger bend radius.
The common types
| Type | Reinforcement | Pressure class | Typical use |
|---|---|---|---|
| SAE 100R1 / EN 853 1SN | One wire braid | Medium | Return lines, pilot lines, low-pressure circuits |
| SAE 100R2 / EN 853 2SN | Two wire braids | High | The general-purpose pressure hose on most machines |
| SAE 100R16 / R17, EN 857 1SC / 2SC | One or two wire braids, compact | High | Tight routing; smaller outside diameter and bend radius |
| EN 856 4SP | Four wire spirals | Very high | Pressure lines in sizes up to about 1 in |
| EN 856 4SH | Four wire spirals, heavy | Very high | Large-bore high-pressure lines, 3/4 in and above |
| SAE 100R12 | Four wire spirals | Very high | High-impulse lines on mobile equipment |
| SAE 100R13 | Four or six wire spirals | 350 bar (5,000 psi) in all sizes | Main pump and travel lines on large excavators |
| SAE 100R15 | Four or six wire spirals | 420 bar (6,000 psi) in all sizes | Highest-pressure circuits and hydrostatic drives |
| SAE 100R3 / R6, EN 854 | Textile braid | Low | Low-pressure return, drain and lubrication lines |
| SAE 100R4 | Textile with a wire helix | Suction | Pump suction lines; the helix stops the hose collapsing |
| SAE 100R7 / R8, EN 855 | Synthetic fibre, thermoplastic tube | Medium to high | Forklifts, aerial platforms, non-conductive lines |
How to read the European codes
- The number is the count of reinforcement layers: 1, 2 or 4.
- S means steel wire.
- N marks a thin cover that needs no skiving. The older T suffix marks a thick cover that must be skived. C means compact.
- P and H in 4SP and 4SH mark the two four-spiral classes: 4SP for small and medium bores, 4SH for large bores at higher pressure.
How to read the SAE codes
SAE types are simply numbered in the order they were standardised, so the number carries no meaning by itself. The ones worth memorising are R1 and R2 for one- and two-wire braid, R12 for four-spiral, and R13 and R15 for the 5,000 and 6,000 psi spiral classes. Suffixes such as AT mean a thin cover for no-skive fittings.
Constant-pressure hoses
On traditional types the working pressure falls as the bore gets larger: a 1/4 in 2SN hose is rated far higher than a 1 in 2SN hose. R13 and R15 are different. They hold the same working pressure in every size, which lets a designer pick one pressure class for a whole machine. Newer ISO 18752 hoses extend this idea across more pressure classes.
Choosing a replacement
Replace a hose with the same type and size as the original, or with a type of equal or higher pressure rating that suits the routing. Moving from braided to spiral increases the bend radius, and the fittings must be approved for the new hose type.
Frequently asked questions
What does 2SN mean on a hydraulic hose?
2SN is the EN 853 code for a hose with two layers of steel wire braid and a thin cover. It is equivalent in construction to SAE 100R2.
What is the difference between 4SP and 4SH hose?
Both have four layers of spiral steel wire. 4SP covers small and medium bores. 4SH is a heavier construction for large bores, 3/4 in and above, at higher pressure.
Is R2 the same as 2SN?
They describe the same two-wire braided construction in the SAE and EN systems. Most two-wire hoses are made to meet both and are marked with both codes.
What hose is used on excavator main lines?
Main pump, boom and travel circuits on large excavators typically use four- or six-spiral hose such as 4SP, 4SH, R13 or R15. Check the machine hose record for the exact type and size.
Useful with this lesson
- Unit and dash-size converter
- Find hose length and fittings by machine model
- Hydraulic fitting types and how to identify them
- How to make a hydraulic hose assembly
Ratings and dimensions here are the nominal values set by the standards. The layline and data sheet of the actual hose take precedence.