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What Do the Numbers on Hydraulic Hose Mean? [Hydraulic Hose Specialist’s Note]

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Table of Contents


You have to be clear about the hydraulic hose specification, and you will see a lot of measuring units in the hydraulic hose size chart.

Here are many numbers printed on the hydraulic hose cover, what do they mean? You will get the meaning of these terms, DN, De, Φ in hydraulic hose.

Here we go!

Hydraulic Hose Layline Numbers

hydraulic hose layline decode
hydraulic hose layline decode

Here are many numbers printed on the hydraulic hose layline, so are you confused about what they mean? And let’s see the hydraulic hose layline decoding.

What Is DN in Hydraulic Hose?

hydraulic hose Nominal Diameter
hydraulic hose Nominal Diameter

Here is the explanation about the hydraulic hose DN meaning: The screenshot is the hydraulic hose specification chart, and you can see DN in the first column.

DN is the abbreviation of Nominal Diameter. DN, Nominal Diameter is also the outside diameter of the hydraulic hose, measured by millimeters.

DN is the measurement in millimeters of the interior of the hose. This measurement of length comes from the English nomenclature. 1 inch equals 25.40 millimeters, also the inside of the hose as a reference.

You can use the vernier caliper to measure the hydraulic hose to get the hydraulic hose DN size.

Inch to MM

inch to mm converter
inch to mm converter


Inch and mm are units of length, used to measure the hydraulic hose length, and here we can use the unit converter to calculate that: How to convert inches to millimeters. 1 inch is equal to 25.4 millimeters.

So you can read the inch size and mm size of the hydraulic hose listed on the hydraulic hose size chart, and different units are used to satisfy measurement of different countries.

What Does Ø Mean?

diameter symbol
diameter symbol

Ø is the diameter symbol. And we can use this diameter symbol to Ø to measure the hydraulic hose size.

As the hydraulic hose standard, we use ID, OD to measure the hydraulic hose diameters.

hydraulic hose id, od

ID: Inner Diameter (or I.D, I.D.) is the span of the empty space in a circular hose cross-section that affects the flow velocity of the fluid within the hose. A hose with an oversized I.D. will result in sluggish system performance problems, while an undersized I.D. can cause excessive pressure drops, leaks, and system damage. So it’s important to get the accurate ID specification, and they are accurate to one decimal point.

OD: Outer Diameter (or I.D, I.D.) measures the entire span of the hose cross-section, including the tube, reinforcement, and cover. The difference between the O.D. and I.D. is the thickness of the hose wall. Outer diameter is important for sizing industrial hoses to appropriate fittings and system components.

How to Measure Hydraulic Hose Length

hydraulic hose length calculation
hydraulic hose length calculation

It’s basically important for you to measure the hydraulic hose length, here is the chart of hydraulic hose length calculation.

Calculating hydraulic hose length before hydraulic hose assemblies is a big task, which can determine that you can route hydraulic hose properly, without any damage to the hydraulic hose body.

To be honest, longer is much better than shorter, you can prepare much more hydraulic hose pipe, based on the accurate calculation. You can use this length calculating formula to work out the final result, in order to plan hydraulic hose installation to avoid any potential barriers, and this can help you expand the hydraulic hose service life to the maximum extent.

What Is Dash Size?

hydraulic hose dash size conversion table
hydraulic hose dash size conversion table

What is the hydraulic hose dash size? This is the asked frequently question for the hydraulic hose starters.

The dash size is also the method to measure the hydraulic hose size, and the dash size can be converted to inches.

Here is the hydraulic hose dash size conversion table, you can calculate the dash size to inches.

Simply put, the dash size equals an I.D. of a hydraulic hose in 1/16″ increments. For example, a -06 hose would indicate a hose with an I.D. of 6/16″ – or 3/8″.

Hydraulic Hose Bend Radius

hydraulic hose bend radius chart
hydraulic hose bend radius chart

You can see the hydraulic hose bend radius chart to get to know the bending capacity of the hydraulic hose pipe.

You can select the hydraulic hose for your hydraulic system, please be serious about the hydraulic hose bend radius. This may cause hydraulic hose kinking when a hydraulic hose goes beyond its rated bend radius.

Hydraulic Hose Working Pressure vs Burst Pressure

hydraulic hose working pressure vs burst pressure
hydraulic hose working pressure vs burst pressure

Hydraulic hose working pressure and hydraulic hose burst pressure are also important for you to consider before selecting a hydraulic hose.

Working pressure:

The working pressure means the pressure of the hydraulic hose in the working conditions range, normally called the pressure range. The hydraulic hose working pressure is used to test the normal pressure range during the working process.

Burst pressure:

The burst pressure is the maximum pressure of the hydraulic hose that can be applied to the components without any physical damage. Burst pressure can be defined as the maximum pressure of a hydraulic hose before breaking. When the pressure exceeds the burst pressure, the hydraulic hose will explode.

The pressure test is necessary to ensure the hydraulic hose safety during its service life, and regularly 1/4 working pressure equals to burst pressure.

Hydraulic Symbols

hydraulic hose symbols
hydraulic hose symbols

Here are some widely used hydraulic hose symbols, and you can get the meaning of these symbols or icons if see them used in the hydraulic hose size chart. And also you can use these to make your hydraulic hose specification pdf.

Final Thoughts

If you have any other questions about the hydraulic hose specifications, please feel free to contact us now. You can ask for FREE hydraulic hose samples from us at any time.