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EPA calls a refrigerant 'high-pressure' if its liquid saturation pressure at 104 F falls in what range?

170 to 355 psia at 104 degrees F.

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  1. 45 to 170 psia
  2. 170 to 355 psia ✔
  3. Above 355 psia

Why: EPA sorts refrigerants by how much pressure the liquid has at 104 F. High-pressure is 170 to 355 psia. Below that is medium, then low-pressure under 45 psia. Above 355 psia, or a critical temperature below 104 F, is very high-pressure.

Huh, didn't know that: Very high-pressure refrigerants include R-13, R-23, R-503, R-508A and R-508B.

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Why do high-pressure refrigerants get promoted? They work well under stress.
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References

Answer: 170 to 355 psia. EPA sorts refrigerants by how much pressure the liquid has at 104 F. High-pressure is 170 to 355 psia. Below that is medium, then low-pressure under 45 psia. Above 355 psia, or a critical temperature below 104 F, is very high-pressure.

  1. 40 CFR 82.152 Definitions (Cornell LII) www.law.cornell.edu/cfr/text/40/82.152
    uses a refrigerant with a liquid phase saturation pressure between 170 psia and 355 psia at 104 °F
    Checked 2026-10-10.
  2. 40 CFR 82.152 Definitions (Cornell LII) www.law.cornell.edu/cfr/text/40/82.152
    R-13, R-23, R-503, R-508A, and R-508B
    Checked 2026-10-10.

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