An evaluation of the international maritime organization's gaseous agents test protocol

The International Maritime Organization (IMO) Maritime Safety Committee's (MSC) subcommittee on fire protection (FP) has developed a test protocol for evaluating the extinguishing effectiveness and critical design parameters of fixed gaseous halon alternative fire extinguishing systems. This paper is an evaluation of the developed protocol based upon its effectiveness in verifying agent distribution throughout the protected space and the effectiveness of the agent against typical maritime fire scenarios. The testing described herein was conducted by the U.S. Coast Guard as part of their evaluation of the developed protocol. Four "halocarbon" agents (NAF-SIII, CEA-410, CEA-308 and FM-200), one "inert" agent (Inergen), one gas/powder mix (Envirogel), and Halon 1301 for baseline comparisons were evaluated with the protocol. The IMO Protocol was found to represent a reasonable basis for evaluating the effectiveness of fixed gaseous fire extinguishing systems. However, the results from testing with the protocol are subject to interpretation due to the lack of a definition of the end of the discharge time. The four fire scenarios that make up the protocol can better meet their respective objectives by modifying the scenarios to reduce the impact on extinguishment of variables other than the uniform addition of agent throughout the space (e.g., oxygen depletion, localized high agent concentrations, and localized high flow velocities).