Magazine Articles
(From the Sept/Oct 2000 Issue of Industrial Fire World)
Baltimore, Md., July 14, 2000 - Ever since Halon 1301 was first identified as harmful to the ozone layer - and production in the developed countries subsequently banned by international treaties - the search for alternative fire suppression agents has intensified. In the process, the search has raised nearly as many questions as it has answered.
Sorting through the technological jumble - not to mention all the competing claims and counterclaims about which agent or system is best for what application - is extraordinarily difficult. It's even more of a challenge for anyone not fully conversant with the minutiae of how Halon replacement issues have evolved over the past few years.
One complicating element is the fact that only the manufacture of Halon is banned, not its actual use as a fire suppressant. In some scenarios, particularly in many military and aircraft applications, Halon was and still is the best or only alternative. The only issue for the future will be the availability and eventual cost of recycled Halon.
There are a range of complex issues beginning with whether to replace Halon, and if so, with what system. No one wants to make the considerable investment in a Halon replacement agent - plus the hardware to deliver it - only to discover that it's not economically or environmentally viable in the long term.
As a direct result of international protocols banning the production of Halon, a varied list of 15 or more classes of chemicals emerged as possible replacement agents. Since then, factors involving toxicity, effectiveness across varied applications, and manufacturing costs have narrowed the list to four gases that are considered to be commercially viable in North America. There are two or possibly three halogenated gases plus other combinations of inert gases that come closest to the fire suppression properties of Halon. But because none of these are as effective, they require larger storage containers and more robust delivery hardware. Also, there are unanswered questions pertaining to how the more chemically stable of these gases will affect global warming. That, in turn, could lead to other regulatory issues.
Cost is another complicating factor in reaching a decision on Halon replacements. The new technology in gases, whether halogenated or inert, is more than double the cost of Halon (both in gas and equipment). Two other fire suppression alternatives are solid propellant aerosols and water mist systems. Here again, each has its own set of advantages and limitations according to the nature of a specific application.
Once Halon was isolated as an ozone problem, the biggest challenge became the formulation of rational "real-world" policies for phasing out Halon and phasing in replacement agents. That process requires an intimate familiarity with a wide range of minute technical details. Beyond this, it requires involvement at the highest levels of national and international forums on the subject, including the bodies that originally framed the international treaties as well as the policies formulated by regulatory agencies.
As to where Halon alternative answers can be found, it is best to look at those who have performed extensive experimentation with alternative agents. The most valuable resources are specialists having had long-term involvement with virtually every facet of Halon replacement, including full-scale tests for replacement agents, delivery systems design, as well as formulating computer modeling software packages aimed at predicting effectiveness and flow behavior. For facilities people, the key is first to recognize the degree of complexity. And second, to find viable and experienced resources to obtain the right answers, and the most effective solutions.
Philip DiNenno is President of Hughes Associates, lnc. Established in 1980, Hughes Associates provides engineering and research services to the fire protection field, including fire hazard and risk assessment services, fire protection system design and testing, fire and building code consulting, plus forensic engineering services. Its clients include architects, building owners and manufacturing companies in addition to the Department of Defense and other governmental bodies. Hughes engineers chaired the National Fire Protection Association's committee for establishing standards for Halon replacement, DiNenno is the author of the "Direct Halon Replacement Agents and Systems" chapter of the NFPA Fire Protection Handbook, 18th Edition. Hughes Associates maintains offices in the U.S., as well as in Europe and Asia. For more information, call (410) 737-8677.
