TFO Series L-ring Face Seal Fittings


  • Reduced internal entrapment
  • Lubricant-free L-ring seal
  • Controlled L-ring extrusion to prevent over-tightening
  • Butt weld connection to ensure the system unhindered
  • Standard surface roughness finished to an average of Ra 20 μin. (0.51 μm)
  • Each fitting marked with size, material and heat number

Technical Data

  • Sizes range from 1/4″ to 1″
  • Materials:
MaterialBar StockDesignator
316 SS
316L SS

Working Pressure

Tube OD.Working Pressure psig (bar)
1/4 in.2500 (172)
1/2 in.2000 (137)
3/4 in.1500 (103)
1 in.1500 (103)
12 mm2000 (137)

Working Temperature:

Temperature ranges for TFO fittings are restricted by the L-ring materials.

MaterialDesignatorWorking Temperature
PTFET– 50°F to 450°F (- 45°C to 232°C)

Testing: Every TFO fitting is Helium leak tested to a maximum allowable leak rate of
4×10−⁹ std cm³/s

Installation Instructions

  1. Assemble the gland, nut and gasket as below. Finger tight the nut
  2. Tighten the nut 1/8 turn with a wrench while holding the fitting body steady


  • Dimensions are for reference only and are subject to change.
  • Inspect the O-ring each time the groove housing is dismantled.
  • Before welding the body , the L-ring should be removed to prevent possible damages.
  • Tungsten Inert Gas Welding (TIG) is recommended.
  • Do not loosen or tighten fittings when system is pressurised.

For more information on TFO Series L-ring Face Seal Fittings please contact our sales team: or call 01942601209.