Hydraulic Hose Layline - Know What it Means and Use It!

In July 2010, we published an article about the importance of what's on the layline of a hydraulic hose - and how to interpret it. Here it is again, this time with a video from Parker Hannifin:

Have you noticed all the writing on hoses manufactured by Parker Hannifin? To most people it looks like mumbo jumbo but to others it is an indispensable source of information. The layline runs the length of the hose, and contains information about the hose's most important properties such as size, working pressure, rating, and more. Smart mechanics and maintenance managers use the information to verify that the right hose is used for their application.

The laylines on Parker hoses include the following information:

	Manufacturer designation In this case, the hose's manufacturer is Parker.
	Part Number The hose part number is 782TC.
	Size Inside diameter dash size is -16, which corresponds to 1". (Dash size refers to sixteenths of an inch, so -16 size correspons to 16/16", which reduces to 1".)
	Working Pressure Working pressure is measured identified in Mega Pascals (MPa) or pounds per square inch (PSI).
	Industry Standards This hose complies with ISO3862-1, and EN856 specifications.
	The Date Code This date code indicates that the hose was made in 1st quarter of 2014. Do not use any rubber hoses older than 10 years. The Society of Automotive Engineers (SAE) specifications states that shelf life of bulk rubber hose is 10 years from the date of manufacture and is considered unlimited for thermoplastic hose, if stored in subdued light and controlled temperatures with no fittings attached.

Sometimes you may also see No-Skive printed on some of your hoses. Skiving refers to removing (or shaving) part of the hose cover and/or inner tube prior to attaching hose ends. No-Skive means the hose and fittings are designed to work without this step. Parker offers more No-Skive hose than any other manufacturer. 

So what is the advantage to you? The hose core is not exposed to possible damage since the cover or inner tubes do not have to be removed to attach the crimped fittings.  A No-Skive hose speeds up the assembly time of a hose assembly, and there is no additional equipment or clean up needed.

We have used Parker hose as an example but other manufacturers use similar laylines.

The layline can also be used as a visual index when routing and tightening the assembly to ensure the hose is not twisted or kinked.

The information contained on the layline should be considered in conjunction with using the STAMP method for hose selection whenever selecting a replacement hose. Understanding the requirements of your system as well as specifications of the hose you are replacing will save time when communicating with a hose fabricator.

Re-posted by Marek Bobik, originally posted by Joni Scott

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