All Fired Up

Choosing the proper special suppressant requires a careful look at project goals

By Kathyrn Rospond, Contributing Writer -- Consulting-Specifying Engineer, 11/1/2004

When it comes to specifying clean-agent fire suppression systems in sensitive environments such as computer rooms or museums, engineers today face a smorgasbord of chemical options. It's no secret that FM-200 and Inergen dominate the clean-agent market, but several alternatives are also now available that may be even better depending on the application. Choosing the proper system, in turn, requires careful analysis of project goals and how a specific system meets those goals.

"What you did before may not be appropriate for every project," says Michael J. Rzeznik, P.E., manager of the New York office of Schirmer Engineering Corp. "When it comes to property protection, you have to think about each case."

The choices out there are many, and Rzeznik says the size of the space to be protected and the amount of clean agent required to serve that space are critical considerations. But engineers must also factor in concerns such as the amount of space needed to store the agent, system maintenance costs and overall system costs.

Before delving further, it's helpful to step back for a moment. Halon, of course, was the traditional chemical of choice before being tagged for eventual phaseout by the Montreal Protocol of 1987 after it was determined to be harmful to the environment. Production was ordered to be phased out by Jan. 1, 1994. Its use in the United States, however, was not banned and, in fact, the agent still exists in many facilities. But with a phaseout coming eventually, most new facilities with special suppression needs have moved on to other agents in the market (see "Sizing Up Halon Alternatives," p. 44). That said, Rzeznik adds that engineers are also considering other options—and whether a halon alternative is even necessary.

According to an industry insider who distributes clean agents, halon was often used simply because it was relatively cheap. "People put it in places where it wasn't really needed and where they could have used something else. Today, people don't remember what they were protecting and why the systems were put in to begin with," says the distributor.

According to John Mahoney, P.E., fire protection specialist with Gage Babcock, Chantilly, Va., applications that once received halon systems may now be seeing water-based solutions, such as water mist. "Things change," Mahoney says. "In some cases, museums wouldn't have halon to begin with."

Likewise, Rzeznik supports a trend toward more water-based systems. In many cases, gaseous fire-protection systems are used where a conventional sprinkler system would be a better and less expensive solution. Transformer rooms and electrical switchgear rooms are two examples where gaseous systems can be overused. "There aren't many cases where you can't use sprinklers vs. halon [or halon alternatives]," Rzeznik says.

Rzeznik also reminds his colleagues that ownership choice and property protection—not building codes—determine where chemical-based suppression systems are used. "The building code doesn't tell you where to install that type of system; it tells you how to install it. Understanding the end users' protection concerns is the best guide when determining if and what kind of gaseous system should be designed," he says.

While clean agents have their place, there's still a lot of confusion out there. "In the days after the halon production bans, people were confused and opted to do nothing. Then FM-200 emerged as the 'choice,'" notes our distributor insider. "Now, there are lots of choices, but people are back to that post-halon confusion. It's not as bad as it was, but it's there."

The good news is that there are a number of informative resources available: NFPA Standard 2001 (2004 edition); UL listings and FM approval guides; the U.S. EPA SNAP list; and individual system manufacturer websites. Our distributor also reminds us that manufacturers are also open to presenting personalized "lunch and learn" sessions.

The trend toward green buildings and the growing importance of LEED certification is another influence on decisions today, adds Rzeznik. Because of both a zero global warming potential and a zero atmospheric lifetime count, Inergen and Chemetron's Argonite, he says, have been popular. The newest player to the green scene is 3M and its Novec 1230 product, which company officials claim has a global warming potential of only 1.0.

From Rzeznik's perspective, the biggest hurdle for some manufacturers of the newer halon alternatives may be overcoming the psychological and emotional ties some engineers may have to certain products.

"There are some engineers who always use the same agent for all applications because they have developed a comfort level with its design, not necessarily because it is the best agent for the job," Rzeznik says. "The bottom line is that all the options work."

That said, he adds appropriate considerations should be given to all of the agents, "particularly if it is in the best interest of the client."