Years ago, it was very simple to choose the appropriate agent for an application. If you wanted to protect the building, you installed a sprinkler system. A lot of piping, connections to the water supply, but very reliable in property protection. However, if you had a special room, such as computer rooms, where water could create more damage than it prevented, Halon 1301 Systems were developed to protect these areas. This agent could suppress a fire, while maintaining a safe environment for people to be in during and after the discharge. This was a large step from using Carbon Dioxide, which was very effective in providing a clean agent to suppress a fire, but people had to evacuate before the discharge, since the concentrations used to suppress a fatal could be hazardous to people.
In the 1990ís, when halogenated fluorocarbons were banned from production in the Montreal Protocol, new agents were developed. One of the first to be developed and which became widely used was (chemical name) , which was also known as FM-200, FE227, FE227e, Sinorex as well as a couple of other names. While this agent was a large environmental improvement over Halon 1301, it still had a measurable Ozone Depletion Potential. Another agent that was developed during this time was Inergen, which, while a more environmentally responsible agent, due to the high pressure cylinders it required, the installation costs were usually higher, and thus didnít gain the wide acceptance that (chemical name) did. Other agents were developed and the most widely used one was NOVEC 1230, also known as Sapphire.
While very similar to FM200, in concentration levels required and type of storage cylinders, it did cost a little more, but it has a very low ozone depletion level, and little global warming potential. Also during this time, another inerting agent was developed, similar to Inergen, called Argonite. Both of these agents have no Ozone Depletion Potential or Global Warming Contribution. However, their installed costs are usually higher than other choices of agents. Offsetting this cost however, is the ability to stay in an enclosure longer than other agents, thus requiring less sealing on the enclosure.
There is also another agent that was developed, that while not widely used, is another choice for designers to consider. FE13 was first widely used on the Alaskan Pipeline due to the extreme cold temperatures. This is the only agent listed for use down to minus 40 degrees Fahrenheit. Most of the other agents are listed for use only to 32 degrees.
Carbon Dioxide has been around for a very long time and is a very effective agent for many applications. While a major drawback to this agent is the potential hazard to people, with the proper safeguards in place, it can be safely used, and is an excellent choice of agents. A major application of this agent is in what is referred to as a Local Application. This is where there is not an enclosure to contain the agent, but the location of the nozzles contains the agent in an area, or where enough agent is provided to cover an area in the open. An excellent example would be a printing press, which is located in a large room. Nozzles can be located close to the press to provide a clean agent to suppress the fire. Another excellent use is in the Power Generating Industry, where it can be used on turbine generators, and in deep seated generator fires.
In addition to the environmental issues affecting the choice of agent, is the ability of the agent to work on the potential fire in the area. While most agents will work on a Class A fire, a slightly different concentration may be required for a fire involving energized electrical equipment (Class C Fires). Flammable liquid fires (Class B Fires) require a more detailed analysis, since the required concentration of agent will be different depending on the material involved.
There are also evaluations that must be performed on other factors involving the design of the room, strength of the enclosure, sealing required, HVAC shutdowns required, damper closures required and other concerns. Not to be overlooked is the area where the agent storage containers will be stored. There must be enough room, the proper temperature, and enough structural support to hold the cylinders.
Other concerns to be addressed are any electrical connections that may be required. Does power to the area or specific pieces of equipment need to be turned off. What manner and type of notification is required in the local area. How is this system going to tied into the Building Fire Alarm system, or will it be directly compatible with it.
All these issues need to be taken into concern when looking at your unique hazard. An experienced consultant is your best source for this analysis. Upstate Fire Protectionís Robert Dyminski is one of the most experienced people in the country.