Detonation Proof In-Line Flame Arrester and Deflagration Proof In-Line Flame Arrester

 The Difference between Detonation Proof In-Line Flame Arrester and Deflagration Proof In-Line Flame Arrester

Flame Arresters are mechanical safety devices that prevent a fire (flame) traveling from one part of a site to another and prevent a flame entering a vessel and igniting vapour

Deflagration is a term describing subsonic combustion propagating through heat transfer where hot burning material heats the next layer of cold material and ignites it. Most “fire” found in daily life, from flames to explosions, is deflagration

When the gas is ignited the flame begins to accelerate. This acceleration results in the build-up of a pressure wave ahead of the flame. Given enough run up distance, this pressure wave can build into a shock wave as the flame speed reaches sonic velocity. This first phase is known as a deflagration.

Once the shock wave reaches a pressure to auto-ignite the gas through which it is traveling the flame front and shock wave couple together forming an unstable detonation.

This deflagration to detonation transition (DDT) is the most severe phase of a pipeline explosion, which can generate flame speeds of >3000m/s and high pressures, over 100bar in some cases.

In short, the deflagration Flame Arrester is designed to stop the initial phase of the explosion and is shorter and lighter than the unstable detonation arrestor, but the Deflagration Flame Arrester has restrictions on its placement within the pipework regarding distance from the source of ignition.

Detonation is different from deflagration as it is supersonic and propagates through shock. Detonation involves a supersonic exothermic front hastened through a medium that eventually drives a shock front propagating directly in front of it. Detonations are observed in both conventional solid and liquid explosives as well as in reactive gases. Gaseous detonations normally occur in confined systems but are occasionally observed in large vapour clouds. They are often associated with a gaseous mixture of fuel and oxidant of a composition, somewhat below conventional flammability limits

Explosion characteristics

Flame Arresters – what can go wrong?
A flame Arrester may not function correctly if:

• It is incorrectly specified in the first place
• It is incorrectly installed
• It is not maintained properly
• It becomes damaged or distorted
• It is blocked or contaminated
• The process conditions are changed
• Plant modifications are made
• Maintenance and Health & Safety law

HS(G)158 states, “Health and safety law requires that plant and equipment is maintained in a safe condition. It is essential that Flame Arresters are well maintained. They should be covered by a program of regular inspection and maintenance so they continue to be effective.”

It also goes on to say, “Keep records of the specification of each arrester, its location and its maintenance history.” These records help to identify if the arrester is suitable for the media that it is protecting. Should the process conditions be changed it can then be easily identified if the Flame Arrester fitted remains suitable for the new conditions.

If you're uncertain about Deflagration and Detonation Flame Arresters, this brief guide to characteristics is designed to help. Of course, for further advice or clarification in any way, please get in touch with one of our experts

KSFTFH TYPE KSFF TYPE KSFE-S TYPE KSFE-A TYPE KSFE TYPE KSFLD TYPE KSFD TYPE KSFD-A TYPE KFD TYPE KSFL TYPE KSFH TYPE KSFI-J TYPE KSFI-A TYPE KSFI TYPE	Deflagration Proof In-Line Flame Arrester
	Deflagration Proof end-Line Flame Arrester
	Detonation Proof In-Line Flame Arrester