Safety Group 645/85-30

Parallel connection from 2, 4 or 5 flashback arrestors 85-30, certified to DIN EN ISO 5175-1, for high flow rates

  • highest quality from the world market leader
  • safety elements: flame arrestor [FA], temperature-sensitive cut-off valve [TV], check valve [NV]
  • every arrestor 100% tested
  • 11.12 X 16.77 inches, 1,760 oz (2X), 2,120 oz (4X)
  • acetylene max. 13,837 scfh (free flow-off)
  • fuel gases max. 96,717 scfh (free flow-off)
  • oxygen max. 65,302 scfh (free flow-off)

This model is also available in Stainless Steel

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WITT Safety groups for reliable protection against dangerous reverse gas flow and flashbacks in accordance with DIN EN ISO 5175-1. For applications with high flow rates. Every safety group 100% tested.


  • a large surface area flame arrestor FA of stainless steel construction extinguishes any dangerous flashback entering the device in any direction
  • a temperature-sensitive cut-off valve TV extinguishes sustained flashbacks long before the internal temperature of the arrestors reaches a dangerous level
  • a spring-loaded check valve NV prevents slow or sudden reverse gas flow forming explosive mixtures in the gas supply

Operation / Usage:

  • in central gas supplies (behind the manifold pressure regulator or in a pipeline system)
  • in thermal processing systems conforming to EN 746-2 (cutting machines, furnace supply equipment)
  • WITT safety groups may be mounted in any position / orientation in pipelines / supply pipes
  • the maximum ambient / working temperature is 60 °C / 140 °F
  • gases: acetylene, natural gas, LPG, hydrogen, oxygen, ethylene, propane (more upon request)


  • annual testing of the check valve, body leak tightness and flow capacity is recommended
  • safety groups are only to be serviced by the manufacturer


  • connection: two-sided female thread (G-; NPT-; RC-thread)

Company certified to ISO 9001
Cleaned for Oxygen Service according to EIGA IGC Doc 13/12/E: Oxygen Pipeline and Piping Systems

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