Submarine Exposure Guidance Levels for Selected Hydrofluorocarbons: HFC-236fa, HFC-23,and HFC-404a (2000)
Chapter: Chemical and Physical Properties
The subcommittee divided the NOAEL by an uncertainty factor of 10 to account for interspecies variability, because there are no human data on HFC-143a, for a 1-hr EEGL of 25,000 ppm.
For determining a 24-hr EEGL, the subcommittee used a 4-week toxicity study in rats, in which the highest tested concentration of 40,000 ppm was the NOAEL (Brock et al. 1996). The NOAEL was divided by an uncertainty factor of 10 to account for interspecies variability for a 24-hr EEGL for HFC-143a of 4,000 ppm.
A 90-day toxicity study (Brock et al. 1996) in rats was used to calculate the 90-day CEGL for HFC-143a. In that study, the highest tested concentration of 40,000 ppm was the NOAEL. The subcommittee divided that value by a factor of 10 to account for interspecies variability and then multiplied that value by 1/4 (to account for exposure for 6 hr per day) and by 5/7 (to account for exposure 5 days per week), which yielded a value of about 700 ppm.
HFC-125
Chemical and Physical Properties
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Common name: |
1,1,1,2,2-Pentafluoroethane |
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Chemical name: |
1,1,1,2,2-Pentafluoroethane |
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Synonyms: |
Pentafluoroethane; HFC-125; fluorocarbon 125 |
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CAS number: |
354-33-6 |
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Structural formula: |
CF3CHF2 |
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Description: |
Colorless gas |
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Molecular weight: |
120.0 |
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Boiling point: |
-48.5°C |
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Density and specific gravity: |
1.35 g/cc at 21°C |
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Vapor pressure: |
1,381 psia at 25°C |
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Vapor density: |
4 (air = 1) |
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Flash point and flammability: |
Nonflammable |
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Solubility: |
0.97 g/L in water at 25°C |
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Autoignition: |
No applicable |
