Hydraulic Hose Dash Size Chart

What it is

For most hydraulic hose, the dash number is the hose inside diameter in sixteenths of an inch. A -8 hose has an 8/16 in, or 1/2 in, ID. The metric equivalent is the DN (nominal diameter) used in EN and ISO hose standards. Fittings use dash numbers too, but on a fitting the dash number refers to the tube OD or the connection size. A -8 hose end and a -8 JIC thread are the "same size" by convention, not by measurement.

How to identify

• Read the dash size or ID on the hose layline.
• Measure the ID at a cut end, or measure the OD and check it against the manufacturer's catalog. The OD varies by hose type, so it cannot identify the dash size on its own.
• Measure the fitting thread and match it to the JIC or ORFS column.

Dash size chart

A dash means no common standard ORFS size is listed here.

Key points

• Exceptions: SAE 100R5, some thermoplastic, PTFE and refrigerant/air-brake hoses use dash sizes based on the equivalent tube OD, not the hose ID. Their real ID is smaller than dash/16 in. Always check the catalog.
• Larger is not always safer. For the same construction, a larger ID usually has a lower pressure rating and a larger bend radius.
• Size hose for flow velocity as well as fit. Undersized suction hose causes pump cavitation.
• A hose end can be dash-matched to the hose but threaded for a different port size (for example a -8 hose with a -10 JIC end). Specify both.

Common mistakes

• Measuring hose OD and calling it the dash size.
• Assuming an R5 "-8" hose has the same ID as an R2 "-8" hose.
• Using the hose dash number to pick a port adapter without measuring the port thread.

Governing standards: SAE J517 (hose sizes and families); SAE J514 (JIC 37°); SAE J1453 (ORFS); EN 853, EN 856, EN 857 and ISO 18752 (DN sizes); manufacturer catalog data.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.