PRODUCT LINES
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FE - 13
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Description
In response to the production phaseout of Halon fire extinguishants, DuPont has
developed FE-13TM
(trifluoromethane) as a replacement for Halon 1301 in applications requiring a clean,
environmentally acceptable, and humanly compatible fire extinguishing agent. It can be
used in the same applications as Halon 1301 but not as a "drop-in" replacement
because of differences in pressure and volumetric efficiency. Because FE-13TM contains no
chlorine or bromine, its ozone-depletion potential is zero.
Performance
FE-13TM
extinguishes fires by both physical and chemical means. Primarily, it raises the total
heat capacity of the environment to the point that the atmosphere will not support
combustion. In practice, however, extinguishment occurs at concentrations less than the
theoretical heat capacity value. This is explained by assuming that the agent also removes
the free radicals that serve to maintain the combustion process.
The extinguishing concentration of FE-13TM for heptane (cup burner method) is 12% by volume. Although it is customary to recommend a design concentration of cup burner plus 20%, DuPont recommends a minimum value of 16%. Under these conditions, when compared with Halon 1301 at a 5% design concentration, it requires 1.7 times as many pounds of FE-13TM to give the same protection. FE-13TM is also effective on Class A fires. The inerting concentration for methane fuel is 20.5% by volume.
| Properties of DuPont Alternative Fire Extinguishant Total Flooding Agents |
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| Property | Halon 1301 | FE-13TM |
| Chemical Formula | CF3Br | CHF3 |
| Ozone-Depletion Potential | 16 | 0 |
| Molecular Weight | 148.9 | 70.01 |
| Boiling Point, °C (°F) | -57.8 (-72.0) | -82.0 (-115.7) |
| Critical Temperature, °C (°F) | 67.0 (152.6) | 25.9 (78.6) |
| Liquid Density at 25°C, g/cm3 (77°F, lb/ft3) | 1.54 (96.01) | 0.67 (41.82) |
| Vapor Pressure at 25°C, kPa absolute (77°F, psia) | 1620 (234.8) | 4729 (686) |
| Heat of Vaporization at 21.1°C, cal/g (70°F, Btu/lb) | 19.7 (35.5) | 17.5 (31.4) |
| Extinguishing Concentration, Heptane, Cup Burner, vol% | 3.5 | 12 |
| Acute Toxicity, ALC or LC50 Rats; 4-hr ppm | 400,000 - 800,000* | >650,000 |
*Estimated values.
Comparison of CO2 and FE-13TM
The higher vapor pressure of FE-13TM suggests its similarity to carbon dioxide, but
its greater liquid density along with the much lower toxicity and extinguishing
concentration merit its consideration for use in place of CO2.
Cylinders rated for CO2 storage would be
similar to those required for FE-13TM.
| Comparison of CO2 and FE-13TM | ||
| Property | CO2 | FE-13TM |
| Boiling Point, °C (°F) | -78.4 (-109.1)* | -82.0 (-115.7) |
| Vapor Pressure at 21.1°C, kPa absolute (70°F, psia) | 5826 (845) | 4299 (624) |
| Liquid Density at 20°C, g/cm3 (68°F, lb/ft3) | 0.75 (48.4) | 0.806 (50.3) |
| Specific Volume at 20°C, m3/kg (70°F, ft3/lb) | 0.547 (8.76) | 0.3425 (5.486) |
| Critical Temperature, °C (°F) | 31 (87.8) | 25.9 (78.6) |
| Extinguishing Concentration, vol% | 28** | 12*** |
| Safety at Extinguishing Concentrations | Life Threatening | Not Life Threatening |
*
Sublimes.**Theoretical minimum for gasoline.
***Cup burner for heptane.
Toxicity
Short-term and extended inhalation studies on animals, including histologic
examination, indicate that FE-13TM
is chemically and biologically unreactive. Although it has not been evaluated as
extensively as Halon 1301, where there are comparable studies, FE-13TM exhibits lesser effects. In 1992, DuPont
sponsored a study to evaluate the cardiac sensitization potential of FE-13TM in dogs. No serious arrhythmias were evoked
after a 5-min exposure to 30% FE-13TM
(and 70% air), followed by an epinephrine challenge. It is not likely that higher
concentrations of FE-13TM
would be used for fire protection in normally occupied spaces because of excessive oxygen
depletion. Nevertheless, one additional test was performed with added oxygen at 50% FE-13TM. Again, no
serious arrhythmias were elicited. Other researchers report that 80% by volume of FE-13TM did not
produce cardiac sensitization in animals. FE-13TM is not a mutagen in the Ames test.
When exposed to open flames, FE-13TM will decompose and produce hydrofluoric acid (HF). The amount of HF will depend upon the size of the fire and the speed of extinguishment. Even at low levels, these decomposition products have a very acrid odor and are easily detected by the human senses. The natural tendency to escape exposure should be heeded.
CompatibilityCompatibilityIn storage, FE-13TM is a very stable compound and in the absence of excessive moisture is not expected to react with common materials of construction such as steel, aluminum, and brass. Likewise, many elastomers and plastics are compatible with FE-13TM. When released under fire conditions, some FE-13TM will decompose, producing hydrofluoric acid, which can react with glass and metallic surfaces. The effects may be negligible where rapid detection and extinguishment minimize decomposition products.
Availability and Approvals
DuPont is now producing FE-13TM in commercial quantities and has the capacity to meet all anticipated fire protection needs.
FE-13TM is listed as acceptable for use by the U.S. Environmental Protection Agency "wherever technical or market conditions warrant." FE-13TM is included in National Fire Protection Standard 2001, where it is identified as HFC-23. At least one hardware manufacturer has received a listing from Underwriters Laboratories. Also, FE-13TM is approved for use in Factory Mutual approved fire extinguishing systems.
ApplicationsApplicationsFE-13TM has the potential to replace Halon 1301 in a broad range of fire extinguishing and inerting applications. Its very low boiling point permits use in temperature extremes ranging from -40°F (-40°C) to 130°F (54.4°C). Therefore, systems containers need not be stored in protected spaces at room temperature. The low boiling point also leads to high volatility and the ability to evenly flood large enclosures, particularly those with high ceilings (7.6 m [25 ft]).