Compliance with air quality initiatives often involves the installation of a vapor collection system (VCS). The purpose of a VCS is to collect and direct vapors to a flare, incinerator or recovery unit. This practice creates a hazardous situation wherein an explosive vapor is tied into an ignition source.
This paper examines nine factors in creating the most severe flame front possible in a practical, full sized piping system. They are: gas types, gas mixtures, pre-ignition pressure, temperature of the ignition energy, temperature of the mixture, ignition location, pipe configuration, protected side restrictions and endurance to stabilized flame. The paper also examines which of these factors are in the jurisdiction of the plant process and those factors for which proof of capability have been demonstrated by commercially manufactured detonation flame arresters in actual tests.
Many certification standards define the acceptance testing of DFA's. They have been evolving and improving over the past two decades. A summary is made of which flame propagation parameters are addressed by various standards.
When reviewed in this context, and applied to practical operating conditions, new levels of confidence and safety are created. The critical variables within the control of the industry are outlined. This information can be applied to reduce the current high frequency of vapor transportation explosions.