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Rexarc Liquid Flashback Arrestor – Maintenance and Safety Guidelines

Annual Flashback Arrestor Maintenance Enhances Safety

Safety is key to those working around gas distribution systems. A Rexarc Liquid Flashback Arrester (LFA) on a system ensures safety and the continued efficient and effective operation. Understanding how the LFA works and its annual maintenance needs will help optimize its performance.

(Sidebar: Rexarc offers various types of arrestors, depending on specific uses and needs. Options are detailed on the website.)

Major Components of the Flashback System

An LFA is installed at the main gas line or head of each branch line to stop backflow or flashback. On the outlet side, a safety relief valve must be installed. The system works to release gas in a safe location and manner should excessive pressure occur. An arrestor works by essentially creating a barrier with liquid to stop a flame within a piping or cylinder system before it reaches upline cylinders. Specific installation instructions must be followed for the arrestor to properly function.

A Rexarc liquid flashback arrestor has four main components:

  • Inlet pipe with a check valve
  • Flow diverter
  • Outlet pipe
  • Relief valve
  • Flash back arrestor (FBA) fluid – Part Number: 1-01-0408

The liquid must be replaced annually, optimally during a shut-down period, which provides an opportunity to check your entire system. The relief valve requires a monthly check to ensure it does not leak. This is accomplished by placing soapy water over the relief valve. If it bubbles, it leaks. Additionally, the relief valve must be re-certified annually.

Rob Moyer of Rexarc explains how a flashback arrestor works in a YouTube video.
Learn more about how a flashback arrestor works from Rob Moyer of Rexarc.

Check Your Entire System

Scheduling these checks and tests also makes this maintenance an integral part of overall operations and ensuring it happens. Conducting tests and maintenance activities at their intended intervals ensures your peak uptime and efficiency.

While your flashback arrestor will help overcome dangerous backflow in a system, regulators and changeover manifolds ensure that pressure is optimally maintained throughout a system for safe operation. Taking time to check for efficient and safe operation of these components of your gas distribution system should be an ongoing priority.

Tests to Perform

As part of a full maintenance routine, Rexarc recommends three tests as part of your recurring maintenance checklist to determine the operational effectiveness of regulators and changeover manifolds:

  • Function test — Indicates that the piece is performing its intended function. There are two parts to this test: increase and decrease.
  • Leak test — checks for leaks around seals and valves.
  • Inert purge — removes potentially flammable oxygen from the system by replacing it with inert gas.

Once the tests are complete, order necessary replacements, install them and test again to ensure proper installation and safe operation.

Regular Maintenance Improves Safety, Efficiency

By conducting regular maintenance checks on your Rexarc Liquid Flashback Arrestor — and checking the rest of your gas distribution manifolds — you ensure safety of your system and your people, while optimizing the operation of your system.

Developing and using a maintenance checklist and repair cadence makes this task easier. Rexarc stocks the supplies you need and simplifies ordering.

Rexarc offers several resources to learn more about LFA and manifold maintenance at Learn more about developing a safety maintenance checklist and routine by contacting your Rexarc representative.

Rexarc is a global leader in gas distribution systems and replacement parts. To learn more about us, visit


Summary – The liquid in a Rexarc Flashback Arrestor must be replaced annually, ideally during a shutdown of your gas distribution system. Developing a recurring maintenance checklist and repair cadence for your entire gas distribution system makes this task become a habit.



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