Halon

The Search for Alternatives

by

Joe Ziemba and Steve Waters

It seemed too good to be true... and perhaps it was...But the advent of both Halon 1211 (bromochlorodifluoromethane) and Halon 1301 (bromotrifluoromethane) opened a new era int he industrial fire protection.

Halon as a "clean agent" which effectively attacked certain fire situations with astonishing success. Perhaps even more remarkable were the unique capabilities of halon which allowed the fire to be extinguished without harming the surrounding area.

All of this has been well documented -- how a fire in a library is defeated without damaging books within the fire incident area; how a fire in a closet adjacent to a computer system is subdued without the sensitive electronic equipment being disabled.

As all good things must come to an end, the phasing out of halon began with a distant rumor int he mid-80s containing strange words and phrases such as "chlorofluorocarbons," "ozone depletion" and "environmental acceptability."

Then, when the Montreal Protocol addressed the apparent link between halon, cholorofluorocarbons, and the depletion of the ozone layer -- the comfortable world of halon fire protection changed forever.

The new catch-words were "alternatives," "essential uses," "replacements" and "drop-ins." All focused on the need to develop new fire agents or re-evaluate old ones, to replace halon where necessary. This led to a great deal of confusion as to what this search would reveal, especially about the future of halon in its most common industrial use -- Halon 1301.

The United States Environmental Protection Agency (EPA) has mandated the phase out of all new Halon 1301 production by December 31, 1993.

Following the phase out, only recycled Halon 1301 will be available to recharge halon systems currently in place.

This obviously raises questions concerning the future of industrial fire systems which currently contain Halon 1301:

Some of these questions will be answered by the initial version of the new National Fire Protection Association (NFPA) 2001 Standard, "Alternatives to Halon 1301," which covers all gaseous agents being proposed as replacements. This document, which has experienced a rocky beginning at the committee level, was approved at NFPA's Fall Meeting in Phoenix.

NFPA 2001 has identified eight candidate halon replacements, but only two appear to have a realistic chance for imminent use (in cylinders manufactured in the United States) in industrial fire systems. These two agents are IG-541, better known as INERGEN, and HFC-227, commonly called FM-200.

Both agents received a recent boost from the EPA's "SNAP" program, which delineates basic alternatives of halon. This document was issued for public comment in May of 1993, with a final ruling expected next May. In essence, SNAP covers the toxicity of every proposed halon alternative agent (which would be used in a normally occupied area) by authority of Section 612 of the Clean Air Act.

Primarily, INERGEN and FM-200 look promising because SNAP offered a positive nod to both in the areas of "environmentally safe" and "people friendly." What this means is that neither contain elements which will further deplete the ozone, nor will they pose unusual dangers to occupants under normal circumstances.

These are two very important considerations since many of the previously developed halon replacements were unable to meet these two critical criteria. When considering the possible use of these two new agents, it is important to understand the pros and cons of both and to anticipate when these replacements will be approved and readily available.

SNAP has identified FM-200 as "hydrofluorocarbon agent that is considered an acceptable alternative to Halon 1301 in occupied and unoccupied areas..." It has zero ozone depletion potential (ODP), is safe to human exposure and leaves no residue.

On the other hand, FM-200 requires more agent to meet extinguishing concentration (66 percent more by weight than Halon 1301 at 5 percent concentration). There is also a concern of hydrogen fluoride as a decomposition product (at 1292oF), which has resulted in FM-200 not yet being recommended for use as a flammable liquid fire suppression system.

The SNAP list defines INERGEN as "approved as a total flooding agent in occupied areas...this blend is designed to increase breathing rates, thus making the oxygen deficient atmosphere breathable for short periods of time...specialists agree that the blend does not pose significant risk...and may pose less risk than does exposure to halocarbon agents."

INERGEN is environmentally safe and does not contain a chemical composition like many other proposed halon alternatives. Like FM-200, INERGEN has a zero ozone depletion potential, it is safe for human exposure, and it leaves no residue.

The major difference between FM-200 and INERGEN is that INERGEN is measured by cubic feet rather than by pounds. The end users costs for INERGEN are approximately 50 cents per cubic foot, while FM-200 costs approximately $28-$32 per pound. End users should get quotes for both agents on an installed cost and the cost of a recharge. In most cases, FM-200 is less expensive to install and more expense to recharge.

While this article provides a brief summary of two replacement agents, only one equipment manufacturer has received UL approval. It is expected that UL approvals for other manufacturers will be granted short and FM approvals are due later.

This formality has not been completely accomplished due in part to the delay in formally accepting NFPA 2001 and with SNAP still pending and not fully approved as well.

Be aware that certain cylinders and sphered originally manufactured for Halon 1301 can be retroffited to hold FM-200. Retrofit cylinders are acceptable, but will never carry a UL or FM approval. However, utilizing retrofit cylinders will make it less expensive to convert a current Halon 1301 system to one using FM-200.

Manufacturers of FM-200 and INERGEN systems are currently selling non-listed systems in many states where regulations do not require a listing. Some states require that all fire protection systems be listed by an acceptable approval agency such as UL or FM. Until listed, these states may grant temporary approval. Manufacturers are forced to sell these new systems prior to approvals due to rapid phaseout of Halon 1301 systems.

Systems installed as non-listed will meet all UL and FM requirements or be changed by the manufacturer and distributor to meet any last minute changes that may occur. Since both agents have been tested already, changes are not anticipated. Systems installed prior to UL or FM listing will never be a listed system.

Joe Ziemba is the executive director of NAFED. Steve Waters is president of the Fireline Corporation, Baltimore, MD.

Reprinted from FireWatch!


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This page is brought to you as a courtesy of the National Association of Fire Equipment Distributors, and was last updated on September 24, 1995.

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