Hose markings look like a code and mostly are one. Once you can read them, specifying a replacement stops being guesswork.
The two families you will meet
EN 853 wire braid. The everyday hoses. 1SN has a single wire braid, 2SN has two. 2SN covers most mobile plant service lines.
EN 856 spiral. Heavier construction with four or more spiral-wound wire layers. 4SP and 4SH are used where pressure or impulse duty is higher: track drives, breakers, high-pressure implement circuits.
You will also see SAE ratings, either instead of or alongside these. SAE 100R1 is broadly comparable to 1SN and 100R2 to 2SN. They are different standards rather than identical ones, but for practical purposes the comparison holds.
The thing most people get backwards
Pressure rating falls as bore increases. The same hose construction in a larger bore holds less pressure, because the force trying to burst it grows with the internal area while the reinforcement does not grow proportionally.
So “2SN” on its own does not tell you a pressure. 2SN in a 1/4 inch bore is rated very high. 2SN in a 1 inch bore is rated far lower. If you are matching a hose, match the bore as well as the grade.
The 4:1 safety factor
Hydraulic hose is built to burst at four times its rated working pressure. That margin exists for real reasons: pressure spikes when a valve slams shut, rubber ageing, heat, and normal manufacturing variation.
It is a design margin, not headroom to use. A hose run above its working pressure is consuming the margin that was covering the spikes, and it will fail early.
Impulse rating matters more than people think
Two hoses with the same working pressure can have very different lives on the same machine, because what kills hoses in service is usually cyclic pressure rather than one steady figure.
Spiral hose is rated for far more pressure cycles than braid. On a circuit that cycles constantly, a breaker line or a baler ram, the impulse rating is the number that decides how long it lasts.
Reading the hose
The lay line printed along the hose carries the manufacturer, the standard, the bore and usually the maximum working pressure. If it is still legible on the failed assembly, that is your specification and there is no need to guess.
If it has worn off, an engineer can identify the construction from the cut end by counting the reinforcement layers. See on-site hose manufacturing.