How to choose a hydraulic hose: 1SN, 2SN, 1SC, 2SC, 4SP and 4SH
What the hydraulic hose construction codes mean and what to check when selecting one: pressure, DN size, medium, temperature and working conditions.
A hydraulic hose is a component whose failure means downtime and, in the worst case, an accident. Choosing "by eye" from the diameter and length is not enough - you need to know the construction type, the pressure, the medium and the working conditions. Below are the key rules we apply when selecting hoses in practice.
What the codes 1SN, 2SN, 1SC, 2SC, 4SP and 4SH mean
The codes describe the hose's reinforcement construction and the standard it is made to. The core (inner layer) and the cover are made of synthetic rubber or plastic, while pressure resistance is provided by steel wire reinforcement.
| Code | Standard | Reinforcement | Key feature |
|---|---|---|---|
| 1SN | EN 853 | one steel wire braid | general-purpose hose for medium pressures, equivalent to SAE 100R1 |
| 2SN | EN 853 | two steel wire braids | higher pressures than 1SN, equivalent to SAE 100R2 |
| 1SC | EN 857 | one braid, compact version | smaller outside diameter and smaller bend radius |
| 2SC | EN 857 | two braids, compact version | like 2SN, but handier in tight spaces |
| 4SP | EN 856 | four spiral wire layers | high pressures and heavy pulsating loads |
| 4SH | EN 856 | four spiral wire layers | construction for the highest pressures in the EN 856 family |
The "SC" (compact) versions have a thinner cover, so they are easier to route in tight places - in return they usually require fittings dedicated to this series. Spiral hoses (4SP, 4SH) are stiffer, but cope better with pressure spikes.
Four questions before you order
1. What is the system pressure?
The hose must have a working pressure not lower than the maximum system pressure, including peaks (pressure spikes when valves switch can be much higher than the pressure set on the pump). For hoses compliant with EN 853, EN 856 and EN 857 the burst pressure is at least four times the working pressure, but that is a safety margin, not an operating range.
Under heavily pulsating loads (cylinders, crimping machines, construction machinery) check the manufacturer's datasheet for impulse test resistance and consider spiral hoses.
2. What DN size?
DN (nominal diameter) affects the oil flow velocity. Too small a diameter means pressure losses, oil heating and noise; too large means unnecessary cost and stiffness. As a rule of thumb the velocity is kept lower on the suction side (around 1 m/s) and higher on the pressure side; exact values depend on the pressure and the manufacturer's recommendations - if in doubt, use the manufacturer's nomogram or ask us.
Size designations in inches and "dash" convert as follows:
| DN | Inches | Dash |
|---|---|---|
| 06 | 1/4" | -4 |
| 08 | 5/16" | -5 |
| 10 | 3/8" | -6 |
| 12 | 1/2" | -8 |
| 16 | 5/8" | -10 |
| 20 | 3/4" | -12 |
| 25 | 1" | -16 |
3. What medium and what temperature?
Standard hydraulic hoses work with mineral oils (HL, HLP, HVLP). For fire-resistant fluids (HFA, HFB, HFC) and other liquids, choose a hose with a core intended for them - check the core material compatibility in the manufacturer's datasheet. The typical temperature range is about −40…+100°C, briefly up to +120°C, but the specific values depend on the manufacturer and the series.
4. In what conditions does the line work?
Pay attention to the bend radius (never bend the hose more sharply than the manufacturer specifies), twisting during installation (the hose must not be twisted around its own axis), abrasion against sharp edges and the external environment (ozone, UV, chemicals). A hose under pressure changes length slightly, so do not install it "tight".
The most common mistakes
- selecting only by the pressure set on the pump, without allowing for peaks,
- bending too sharply right at the fitting - leave a straight section behind the crimp,
- a twisted hose after installation,
- combining a hose, a ferrule and a fitting from different systems without confirming that they form an approved combination - the crimped fitting should be selected according to the hose manufacturer's recommendations.
Where to choose a hose
Our range includes hydraulic hoses (1SN, 2SN, 1SC, 2SC) and high-pressure hoses (4SP, 4SH and related). We pull prices and availability live from the warehouse, and if you are not sure about the selection, write to us through a quote request or the chat.
This article is for information only and does not replace the manufacturer's documentation or design calculations. The final selection of a hose for a specific system is the responsibility of the designer or the user of the installation.