Product information

Maritime authorities, such as the Norwegian Maritime Directorate, require the installation of flashback arrestors for acetylene and oxygen, as incorrect maintenance or use of gas welding equipment may cause flashbacks of various types.

Normally these will stop in a well designed torch, and are only noticed as a popping sound in the torch. However, faulty handling, maintenance or gas pressure setting may lead to a penetrating flashback. This means that the gas flame passes back through the hose(s). In some cases it may also pass the regulator and ultimately reach the cylinder.

The in line Acetylene flashback arrestor is the final safety feature to prevent flashback / decomposition from advancing to the high pressure part of the gas distribution system. In line Oxygen flashback arrestor is available as an accessory.

The flashback arrestors supplied by Unitor are designed for use both with gas cylinders and gas outlet stations and incorporate several safety functions:

  • Non-return valve preventing reverse flow of gases, thereby preventing a gas mixture from reaching pipelines or cylinders
  • Flame filter to quench the flame front of a flashback or a burnback
  • Temperature activated cut-off to prevent further gas supply in case of fire (activated if the temperature rises to approximately 100° C).
  • Pressure activated cut-off to prevent further gas supply after a flashback (activated by the pressure shock in front of the flashback).
  • The flashback arrestors are build Conform to: EN 730/ISO 5175 and with BAM Certification no.: ZBF/009/12


For safety reasons we strongly recommend annual testing of the Flash back arrestors, and to change flashback arrestors every 5 years. For vessels under OCIMF SIRE VIQ 7, replacement of the flashback arrestor is mandatory after 5 years from date of manufacture.

Some Class/Flag states (or other organisations (like OCIMF) will require yearly testing and replacement 5 years after production. The production date is on the flashback arrestor.


  • Flame arrestor
  • Thermal valve
  • Non-return valve
  • In line Acetylene flashback arrestor


  • Stops the pressure front
  • Prevents fire from being supported by gas
  • Stops the flame front
  • Stops gas from back feeding into the system