Click here for a printable version of this article.

March 2006: Halon Alternatives

Bromochloroflourocarbons (Halons) were developed in the 1930s. Halon is low in toxicity, non-flammable, non-corrosive and very compatible with many materials. Halon has thermodynamic and physical properties that make it ideal as a fire extinguishing agent and explosion suppressant. However, the stability of the compounds in Halon coupled with their bromine content has linked them to depletion of the earth's protective ozone layer. As a result, Halon and related compounds have been phased out of production beginning back in January 1994.

Since the halting of Halon production, several products have been developed as replacements. Unlike Halon, none of these replacements have the atmospheric affect to the earth's ozone layer.

Alternatives currently include traditional suppression systems, inert natural gas systems (Inergen, CO2), halocarbon systems (FM-200, FE-25), vaporizing pressurized fluid (Novec 1230) or other options such as water mist protection.

Basic details of current extinguishing agent alternatives are as follows:

- Carbon Dioxide: Can provide fire control similar to that provided by Halon. Can be used on surface fires or deep-seated fires. Life safety concerns are created if it is used in an occupied area.

- Recommended Uses: Flammable/combustible liquid applications, electrical equipment.

- HFC-125: HFC-125 (FE-25, pentafluoroethane), produced by Dupont, currently provides the closest match to Halon with respect to extinguishing effects. This makes it ideal for retrofit work.

- Recommended Uses: EDP/Telephone rooms, clean rooms, museums/libraries. Also applicable for total flooding applications such as chemical storage rooms, industrial process control rooms, semi-conductor manufacturing facilities, petrochemical facilities and paint lockers. FE-25 is also being used to protect the engine nacelles of aircraft such as the F/A-18 E/F and V-22.

- HFC-227ea: Manufactured by Great Lakes Fluorine Chemicals, HFC-227ea (FM-200) was the first environmentally acceptable replacement for Halon 1301.

- Recommended Uses: EDP/Telecom rooms, museums, art storage, printing operations, bank vaults airport/satellite uplink buildings, generator/turbine enclosures. Also used extensively in marine applications, as well as the medical field to protect MRI and X-Ray equipment and associated laboratories.

- Novec 1230: This is one of the newest products produced by 3M Company. It is a fluid that vaporizes when applied. The agent extinguishes fire by heat absorption.

- Recommended Uses: EDP/Telecom rooms, military/commercial aviation, racecars, pleasure craft, mass transit vehicles. Used extensively in the commercial marine applications. Also used in the oil and gas exploration/processing industry to protect platform helipads and storage tanks.

- Inert Gas Systems: Inert gas systems employ naturally occurring gases that have no environmental impact. The three main gases are Argonite (IG-55), Argotec (IG-01) and Inergen (IG-541). These gases require greater concentrations to achieve extinguishment than other products.

- Recommended Uses: Automated EDP tape libraries, various hospital applications including MRI and X-Ray equipment, power generation equipment, historic sites, art galleries and libraries.

The following chart provides a summary of the above products:

Agent
Conc.
NOAEL
Safety Margin
ODP
GWP
ALT
Novec 1230
4-6%
10%
67-150%
0
1
5 days
HFC-227ea
4.5-8.7%
9%
3-20%
0
3,500
33 years
HFC-125
8-11.5%
7.5%
0%
0
3,400
32.6 years
Inergen
38-43%
43% (approx)
7-13% (approx)
0
Not Rated
Not Rated
Argotec
38-43%
43% (approx)
7-13% (approx)
0
Not Rated
Not Rated
Argonite
38-43%
38-43% (approx)
7-13% (approx)
0
Not Rated
Not Rated

Conc: Concentration of Gas Required
NOAEL: No Observable Adverse Effect Level
GWP: Global Warming Potential (CO2 = 1)
ODP: Ozone Depletion Potential
ALT: Atmospheric Lifetime

Additional information can be found in the following NFPA Standards:

- NFPA 2001: Clean Agent Fire Extinguishing Systems

- NPFA 12: Standard on Carbon Dioxide Extinguishing Systems

- NFPA 12A: Halon 1301 Extinguishing Systems

Risk Logic can assist in recommending the necessary suppression system for adequate protection of manufacturing or EDP operations.