Selecting a Detonation Arrester

Deciding whether or not a detonation arrester is required can be a challenge even to experienced engineers. The following information aims to provide some relevant information and guidance, but if there is any doubt please contact the Elmac customer services team who will be happy to help.

Are there specific rules when selecting a detonation arrester?

• The operating pressure must be less than or equal to the tested pressure; the operating temperature must be within the product range
• The maxiumum experimental safe gap (MESG) value of the operating gas (gases) must be equal to or greater than that approved (gas group) for the detonation arrester
• The pipe connection size on the unprotected side must be the same or less than the nominal pipe size of the detonation arrester
• It is necessary to account for the pressure drop
• Compatibility of the arrester material and gas should be considered
• The arrester will meet national/international standard/regulation such as ATEX

How do I know when I should use a detonation arrester?

• A detonation arrester will provide maximum protection for all piping systems
• When the ratio of the pipe length (between the potential ignition source and the arrester ) L, and the pipe diameter D, is larger than 50, i.e., L/D > 50
• When multiple bends are involved in the pipe system
• When any other factors/pipe fittings such as obstacles may cause detonation to occur
• When ignition may be caused by a very strong ignition source such as a jet flame

What impact will a detonation arrester have on my system?

• A detonation arrester may cause a significant increase in pressure drop
• Possible clogging/fouling if the gas is not clean (and if the arrester is not maintained properly)

Is there a rule of thumb guideline for selection?

• Select (a) correct arrester size, (b) operating pressure and temperature, (c) gas group
• Ensure any maxiumum pressure drop criteria is met (for a given flow rate)
• It may be necessary to take into account material compatibility
• If an endurance burning condition is possible, at least one temperature sensor must be installed on the flame approaching side of the arrester

Who can advise me on product placement/selection?

The Elmac customer service team will be happy to advise you on any aspect of detonation arrester suitability and selection.

More on detonations

1. What is a Detonation?
2. Stable and Unstable Detonations
3. Deflagration vs Detonation Arresters
4. Selecting a Detonation Arrester

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