Lesson 5 of 5 · Layline
How to read a hydraulic hose layline
The line of text printed along a hose tells you its maker, type, size, working pressure and date of manufacture. It is the first thing to read on any hose.
What the layline is
The layline is the continuous line of printing along the cover of a hose. It repeats every few hundred millimetres so that any length cut from the reel carries the full identification.
It also has a second use. Because it is printed straight along the hose, a layline that spirals around an installed hose shows that the hose has been twisted.
What is printed on it
- Manufacturer and product name.
- Hose type and standard, such as EN 853 2SN or SAE 100R2AT.
- Size, usually in more than one system: DN12, 1/2", -08.
- Maximum working pressure, in bar, MPa or psi, often marked WP.
- Date of manufacture, as a quarter and year or a week and year.
- Sometimes approval marks such as MSHA for flame resistance, and a batch number.
A worked example
A layline reading "EN 853 2SN DN12 1/2" WP 275 BAR 3Q24" means: a two-wire braided hose built to EN 853 type 2SN; 12 mm nominal bore, which is 1/2 in; maximum working pressure 275 bar; made in the third quarter of 2024.
With those four facts — type, size, pressure and age — the hose can be replaced like for like and matched to the correct fittings.
When the layline is unreadable
- Look for a section protected by a clamp, sleeve or bracket where the print has survived.
- Measure the bore at a cut end and the outside diameter.
- Count the reinforcement layers at the cut and note whether they are braided or spiral.
- Check the machine hose record for the original type, length and fittings.
Why the date matters
Rubber ages even on the shelf. Industry guidance commonly limits the storage of bulk hose and of made-up assemblies before they should be inspected and tested or scrapped. Read the date code before using old stock, and follow the hose manufacturer storage rules.
Frequently asked questions
What is a hose layline?
The line of text printed along the cover of a hose. It gives the manufacturer, hose type, size, working pressure and date of manufacture.
How do I find the size of a hydraulic hose?
Read the layline. The size is printed as a DN, an inch fraction or a dash size. If it is worn away, measure the inside diameter at a cut end.
How do I read the date code on a hydraulic hose?
Most show a quarter and year, such as 3Q24 for the third quarter of 2024, or a week and year. The format varies by manufacturer.
What does WP mean on a hose?
WP stands for working pressure: the maximum pressure the hose is rated for in service.
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.