Decomposition Arrestor FN12 / FN40

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Decomposition arrestor, stops dangerous decomposition of acetylene in low-pressure pipelines

  • highest quality from the world market leader
  • safety elements: flame arrestor [FA],  temperature-sensitive cut-off valve [TV]
  • stops the explosive decomposition of acetylene via pressure-controlled quick-acting piston valve
  • every device is tested before delivery
  • BAM certified
  • 70 X 160/200 mm, 3.091-3.846 g
  • FN12 Q= approx. 76 m³/h (free flow-off)
  • FN40 Q= approx. 140 m³/h (free flow-off)


WITT Decomposition Arrestors for reliable protection against decomposition of acetylene and flashbacks of fuel gases. Every Arrestor 100% tested.

The best Safety Devices in the world

  • a large surface area flame arrestor FA of stainless steel construction:
    - stops dangerous decomposition of acetylene independent from flow direction
    - 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 arrestor reaches a dangerous level

Operation / Usage:

  • as a Decomposition Arrestor for acetylene in medium-pressure pipelines for protection of cylinder equipment and bundles in accordance with EN ISO 14114
  • as a safety device (FN40) to protect against flashbacks in accordance to DIN EN ISO 5175-1 - not for acetylene
  • as a Decomposition Arrestor to protect pipelines in supply systems
  • FN40 for double flow capacity
  • WITT Decomposition Arrestors / safety devices may be mounted in any position / orientation
  • the maximum ambient / working temperature is 70 °C / 158 °F


  • it is recommended that an annual body leakage test is performed
  • Decomposition Arrestors / safety devices are only to be serviced by the manufacturer

Company certified to ISO 9001 and PED 2014/68/EC Module H
CE-marked in accordance with 2014/68/EC


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Decomposition Arrestor FN12 / FN40 is used in following areas:


WITT Zentrale

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Headquarters: +49 (0)2302-8901-0
WITT UK: +44 (0)1925 234466

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