Tornado Technologies Inc

Detonation & Flame Arrestors

What is the purpose of an arrestor?

Flame/Detonation Arrestors are passive safety devices designed to prevent the propagation of flame fronts back through lines and piping configurations, and between combustion units and tanks. This is also known as "flashback". When correctly installed, the devices will extinguish flame fronts travelling from either direction.

Basically, all flame and detonation arrestors work on the same "heat absorption" theory:

  • Disperse the flame front
  • Release its energy
  • Cool flame to below ignition point of the gas/vapour contained in the system

Where does a flame front come from?

Any ignition source, such as a flare or incinerator, poses a potentially explosive opportunity for flame fronts to propogate back through lines, destroying facilities and causing injuries. Flame fronts can propagate either slowly, as when burning at the top of a flare stack or burner, or very quickly, as occurs with a deflagration or detonation event that flashes back through a pipeline.

Regardless of pipe diameter, a flame front experiences a rapid velocity increase over a relatively short distance. Once it reaches sonic velocity, the flame front propels a shock wave that is capable of blowing right through conventional flame arrestors. To ensure plant safety, Tornado Technologies recommends Detonation Arrestors be used when installed greater than 10-feet from the ignition source.

As a general rule of thumb, 10-feet is a recommended cutoff point for choosing DA’s versus FA’s.

What are the different types of arrestors?

Arrestors can be divided into two families: Detonation Arrestors and Deflagration (Flame) Arrestors. Using the correct type for your application is critical. Installing a flame arrestor where, in fact, a detonation arrestor is required can have disastrous consequences.

  Flame Arrestors Detonation Arrestor
Prevention:
  • Deflagration (rapid burn)
  • Detonation (explosion)
Applications:
  • Low velocity
  • Non "air-enriched" gas streams
  • Low pressure (< 10 psi)
  • NEC Group D vapours
  • High velocity
  • Any type of gas stream
  • Low pressure (< 10 psi)
  • NEC Group D, C, B vapours
Installation:
  • Within 10-feet of ignition source
  • At any point in the line
Flame Cell:
  • Crimped ribbon
  • Aluminum or stainless steel
  • Welded or removable
  • Stacked plate grid
  • Alumina ceramic media
  • Entire cell removable
Body:
  • Carbon or stainless steel
  • Carbon or stainless steel

How should arrestors be installed?

Tornado Flame and Detonation Arrestors can be mounted vertically, horizontally or at any angle. It is recommended, however, that our FA’s and DA’s be mounted either vertically or at a 45º angle to allow for fluid drain. Any liquids that may travel though the unit can plug off the cell and cause an increased pressure drop over time. By mounting the unit on an angle or vertically, the liquids will not accumulate but pass through the unit and help to eliminate any blockage.

20-degree

Vertical

Horizontal

45-degree (recommended)

Units may be mounted horizontally, however, a regular maintenance schedule should be enforced more often to check for fluid accumulation (a regular maintenance schedule is recommended regardless of the installation angle). Drain plugs are mounted on the DA’s as a standard feature and can also be installed on the FA’s. These will allow the end user to remove liquids that may be trapped in the unit prior to a blockage occurring. Again, Tornado recommends that this be done as a regular maintenance program.