How Flame Arrestors Work

A flame arrestor is a passive safety device fitted to the vent pipe of a storage tank or process vessel that prevents the propagation of flame from the external atmosphere into the tank (end-of-line configuration) or between connected piping sections (in-line configuration). The core component is a flame element — typically a crimped metal ribbon or sintered metal matrix — with precisely engineered gaps smaller than the Maximum Experimental Safe Gap (MESG) for the target gas group.

When a flame front reaches the arrestor element, the narrow passages extract heat from the combustion gases faster than the reaction can generate it, extinguishing the flame. The element also quenches free radicals that sustain combustion. This principle is governed by ISO 16852 (international) and EN 12874 (European) standards, which define performance testing requirements including deflagration, detonation, and endurance burn testing.

End-of-line flame arrestors are installed at the vent outlet of atmospheric storage tanks storing flammable liquids. In-line detonation arrestors are installed in piping systems where flame could propagate between connected vessels. The selection depends on the gas group (IIA, IIB, IIC), the potential flame propagation mode (deflagration vs detonation), and the pipe configuration (distance from ignition source).

Key Technical Specifications

Applications by Industry

• Storage Tank Venting: Installed on PVRV outlets or vent pipes of tanks storing Class I flammable liquids (flash point < 37.8 C)
• Process Piping: In-line detonation arrestors in vapor recovery systems, flare lines, and interconnected vessel piping
• Vapor Combustion Systems: Flame arrestors on vapor collection headers upstream of thermal oxidizers or vapor combustors
• Marine Loading: Vapor recovery systems at marine terminals and loading arms

Certifications & Compliance

Wanan flame arrestors are certified to ISO 16852 (performance), ATEX Directive 2014/34/EU (explosive atmospheres), and EAC (Eurasian Conformity for CIS markets). Each unit undergoes flame transmission testing, endurance burn testing (for in-line detonation types), and hydrostatic pressure testing at 1.5x design pressure. Material certificates per EN 10204 3.1 are provided with all shipments.