SAE O-ring face seal (ORFS) fittings seal liquids and gases from vacuum to 6000 psig. ORFS fitting can be applied to tubing or pipe. They are very versatile fluid connectors because they work exceptionally well on both fluids and gases. They are “zero clearance” fittings meaning that they can be inserted and removed from systems without cutting or flexing the pipe or tubing. This makes them ideal for systems requiring frequent maintenance and for valves and other components requiring periodic maintenance or replacementP-C Render

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  • Working Pressure: Vacuum to 6000 psig
  • Temperature Rating: Up to 400° F (204° C)
  • Body Materials: 316/316L SS, and Alloy 400
  • O-ring Materials: FKM (Standard), Buna
  • Sizes: 1/8 to 2 in.
  • End Connections: ORFS, NPT, BSP, SAE, NPSM
  • Shapes: Straight, Elbows, Tees, Bulkheads


The Soft-Seal fitting assembly consists of four parts: threaded fitting body with o-ring groove, o-ring, nut, and sleeve or tailpiece. The standard o-ring is Buna-N. Other o-rings have been tested and are available for special applications.

The fitting assembly seals when the bottom of the sleeve or tailpiece, which has been fixed to the tubing, compresses the o-ring in the face of the threaded fitting body as the fitting nut is threaded onto the external threads on the fitting body. The threading process draws the sleeve into full contact with the face of the fitting. Sleeves or tailpieces can be secured to the tubing either by brazing, welding, or mechanically flanging the tubing.

  • Zero clearance system – No need to spring or pull the tubing to insert or remove a fitting or other components for installation or maintenance.
  • Unlimited remakes – Fittings can be disassembled and reassembled many times. Simply replace the o-ring and tighten to recommended torque.
  • Forgiving assembly – Soft Seal fittings conform well to irregularities in the fitting face or sleeve. So, while proper technique and handling should be observed during assembly, the tube fitting is forgiving of assembly variation.


Type 316 stainless steel is the standard material on all bodies and nuts. Type 316L (low carbon) is used for sleeves/tailpieces. Buna-N is the standard o-ring material for SAE and NavSea.


Suggested Applications for Soft-Seal Tube Fittings

Soft-Seal tube & pipe fittings are highly recommended on high vibration systems because the soft seal absorbs shock better than metal-to-metal sealing systems.

While the SAE Soft-Seal originated for use in off-road construction machinery, it is gaining popularity in other transportation-related applications such as alternative fuel systems (CNG/LPG) for vehicles. It is endorsed by ISO Technical Committee 131 for all new hydraulic system design.