is it desirable, more then likely not
does the standard allow it, looks like it
5.4 Design Concentration Requirements.
5.4.1 The flame extinguishing or inerting concentrations shall be used in determining the agent design concentration for a particular fuel. For combinations of fuels, the flame extinguishment or inerting value for the fuel requiring the greatest concentration shall be used unless tests are made on the actual mixture.
5.4.2* Flame Extinguishment.
5.4.2.1 The flame extinguishing concentration for Class B fuels shall be determined by the cup burner method described in Annex B.
CAUTION:Under certain conditions, it can be dangerous to extinguish a burning gas jet. As a first measure, the gas supply shall be shut off.
B.1 Introduction. Total flooding fire extinguishing systems are widely used for protection of enclosures where flammable materials, including liquids and gases, are processed or stored.1 The fire extinguishing agent used in such a system can be a gas or a liquid under storage conditions. When released into the atmosphere of the protected space, the agent disperses, evaporating if initially a liquid, to form a mixture of air and gaseous agent. Successful fire suppression occurs when the agent concentration exceeds the minimum extinguishing concentration (MEC) by a sufficient margin, or safety margin, to cause rapid flame extinguishment. Use of excessive amounts of agent may be undesirable for reasons related to total system cost or, often more important, the need to avoid creating an agent-air atmosphere that is harmful to people due to hypoxia, agent toxicity, or both. In the case of flammable liquid hazards, the minimum design concentration (MDC) of a gaseous agent is specified in national and international standards as the MEC times a safety factor. This test method uses the cup burner to determine, for a given fuel, the MEC of a gaseous agent. The cup burner method is inherently empirical. The theoretical and parametric aspects of flame extinguishment in this procedure have been addressed by many authors and is the subject of ongoing research. A few recent references are given in the endnotes to this annex.2,