1 What Halon Alternatives Are There?
In response to the ban on Halon 1301 manufacture, the fire suppression industry has responded with the development of alternative clean agents that pose less of a threat to the ozone layer. Two classes of agents have emerged as suitable replacements: halocarbon-based agents and inert gas agents. The halocarbon-based agents are carbon-based compounds and extinguish fire primarily via the absorption of heat. Inert gas agents are based on the inert gases (i.e., nitrogen, argon, carbon dioxide) and extinguish fire via oxygen depletion.
Under its Significant New Alternatives Policy (SNAP) program, the U.S. Environmental Protection Agency (EPA) is required to evaluate alternative chemicals and processes intended to be used in place of ozone-depleting substances to ensure that they are acceptable from a human health and environmental perspective. Click here
to download PDF files of tables that list all of the agents that are considered acceptable as Halon alternatives under EPA's SNAP program.
With the advent of the new clean agents, businesses worldwide will continue to have the ability to protect critical equipment and irreplaceable items, despite the ban and inevitable disappearance of Halon 1301 from the marketplace. With the mandated decommissioning of Halon 1301 in the EC and the increasing pressure from governments worldwide to reduce dependency on ozone depleting substances, it is expected that the future will see an increased utilization of Halon alternative clean agents.
2 How Do the Alternatives Compare to Halon?
Although the Halon 1301 alternatives are only approximately 70% as effective as Halon 1301 at extinguishing fires, the alternatives have similar characteristics. Like Halon 1301, the new agents are clean (i.e., they leave no residues following extinguishment). As a result, no cleanup is required after discharge of the agents. Because the agents form no corrosive or abrasive residues they are suitable for use on delicate, expensive assets that might otherwise be destroyed by non-clean agents such as foam or water (e.g. books, paintings, cultural heritage items). The clean agents are non-corrosive and non-conductive, and hence can be employed for the protection of sensitive electrical and electronic equipment. Most of the new agents are nontoxic at their typical design levels, and hence are acceptable for use in occupied areas. The clean agents are gases, and can thoroughly flood a protected area, affording rapid extinguishment of even obscured or hard to reach fires. The clean agent systems are applicable to Class A, B and C fires. When coupled with an early detection system, clean agent systems provide rapid extinguishment, reducing equipment damage and ensuring the safety of personnel within the fire area.
Appearance-wise, clean agent systems are similar in many aspects to Halon 1301 systems, although, in general, none of the clean agents can serve as a complete drop-in replacement for Halon 1301: all require modification to the piping systems and or nozzles and system cylinders. Halocarbon agents are stored as compressed liquefied gases, and systems are typically super pressurized to 25 or 40 bar with nitrogen, with the exception of FE-13, which does not require super pressurization. Inert gas agents are supplied in high-pressure gas cylinders, typically pressurized to 200 or 300 bars. For both halocarbon and inert gas systems, additional system components include the usual collection of selector valves, piping, and nozzles.