Seal-Lok H2 / O-Lok H2 - High-Pressure Leak-Free O-Ring Face Seal Fittings

  • Proven leak-free connection for critical hydrogen applications.
  • Multiple O-ring compounds available to meet most H2 application demands
  • Excellent vibration performance
  • Tested in accordance with EC79 and HGV3.1
  • Easy torque assembly and resistant to overtightening
  • Multiple tube connection methods are available.
  • Parker Parflange® tube forming technology makes fast, leak-free connections for Seal-Lok H2 / O-Lok H2. Equipment is available for purchase or rent.
  • Tube end connections can also be created with brazing and welding.

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Seal-Lok H2 (USA) and O-Lok H2 (Europe) O-ring Face Seal Fittings

  • Seal-Lok H2 (USA) / O-Lok H2 (Europe) O-Ring Face Seal Fittings provide a proven leak-free connection specifically designed for critical hydrogen applications.
  • Engineered to withstand high pressures, vibrations, and demanding operational conditions, these fittings ensure long-term reliability and safety.
  • With multiple tube connection methods and Parker’s Parflange® tube forming technology, assembly is fast, repeatable, and resistant to overtightening.
  • Available in both US (Seal-Lok H2) and European (O-Lok H2) versions, they meet global hydrogen standards, including EC79 and HGV3.1.
  • Tested in accordance with HGV3.1 and EC79
  • H2 compatible O-rings, including PU, EP, FKM, and HNBR
  • 700 bar / 350 bar system pressure capability
  • SAE and ISO O-ring boss port ends available
  • Excellent resistance to vibration- induced connection damage and loosening
  • Easy torque assembly with high repeatability and over torque toughness
  • Flat face zero clearance connection provides tube routing and repair ease
  • 316/316L construction

Key features

  • Proven leak-free O-ring face seal design for hydrogen service.
  • Multiple O-ring compounds (PU, EP, FKM, HNBR) to match diverse H2 application requirements.
  • Excellent vibration performance to prevent loosening or damage.
  • Easy torque assembly with high repeatability and overtightening resistance.
  • Flat face zero clearance connection for easier tube routing and repair.
  • Multiple tube connection methods: Parflange® forming, brazing, and welding.
  • Equipment available for purchase or rent for tube forming.

Technical specifications

  • Standards Compliance: EC79, HGV3.1
  • Pressure Capability: 700 bar / 350 bar system pressure
  • Materials: 316 / 316L stainless steel
  • O-Ring Compatibility: PU, EP, FKM, HNBR
  • Port End Options: SAE and ISO O-ring boss
  • Design: Zero clearance, flat face connection

Application areas

  • Hydrogen fuel systems
  • High-pressure H2 distribution and storage
  • Hydrogen-powered vehicles (compliant with EC79 & HGV3.1)
  • Critical hydrogen processing and industrial applications

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  • Parker Hannifin has the right seal fittings for you. Fill out the contact vendor form to contact the vendor.
Parker Hannifin

Parker Hannifin is a Fortune 250 global leader in motion and control technologies. For more than a century the company has been enabling engineering breakthroughs that lead to a better tomorrow. Parker is supporting the global decarbonisation efforts through a broad range of solutions, hydrogen-compatible components and systems enabling safe and efficient operation for a variety of applications.

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