2.3 Common Refrigerants Reference Guide

2.3 Common Refrigerants Reference Guide

This section provides a detailed reference for the refrigerants most commonly encountered on the EPA 608 exam and in the field. Understanding each refrigerant's properties, applications, and regulatory status is critical.

CFC Refrigerants (Phased Out — Legacy Equipment Only)

R-11 (Trichlorofluoromethane) — CFC

• Category: CFC, Class I ODS
• ASHRAE Safety: B1 (higher toxicity, non-flammable)
• ODP: 1.0 (reference standard)
• GWP: 4,750
• Boiling Point: 74.9°F (23.8°C) — boils at room temperature
• Status: Production banned since 1996
• Applications: Low-pressure centrifugal chillers (legacy)
• Key Fact: Used as the ODP reference standard; boils above room temperature making it a low-pressure refrigerant

R-12 (Dichlorodifluoromethane) — CFC

• Category: CFC, Class I ODS
• ASHRAE Safety: A1
• ODP: 1.0
• GWP: 10,900
• Boiling Point: -21.6°F (-29.8°C)
• Status: Production banned since 1996
• Applications: Automotive AC (pre-1994), household refrigerators (legacy), commercial refrigeration (legacy)
• Key Fact: Has the highest GWP of any commonly discussed refrigerant (10,900)

HCFC Refrigerants (Being Phased Out)

R-22 (Chlorodifluoromethane) — HCFC

• Category: HCFC, Class II ODS
• ASHRAE Safety: A1
• ODP: 0.055
• GWP: 1,810
• Boiling Point: -41.4°F (-40.8°C)
• Pressure at 70°F: ~121.4 psig
• Status: No new production or import since January 1, 2020. Only reclaimed/recycled R-22 available
• Applications: Residential/commercial AC, heat pumps, commercial refrigeration (legacy systems)
• Key Fact: Still the most commonly encountered HCFC in the field; can only be obtained as reclaimed or recycled

R-123 (2,2-Dichloro-1,1,1-trifluoroethane) — HCFC

• Category: HCFC, Class II ODS
• ASHRAE Safety: B1 (higher toxicity)
• ODP: 0.02
• GWP: 77
• Boiling Point: 82.2°F (27.9°C) — boils above room temperature
• Status: Being phased out by 2030
• Applications: Low-pressure centrifugal chillers
• Key Fact: Boils above room temperature (like R-11), making it a low-pressure refrigerant. Classified B1 (toxic)

HFC Refrigerants (Being Phased Down)

R-134a (1,1,1,2-Tetrafluoroethane) — HFC

• Category: HFC
• ASHRAE Safety: A1
• ODP: 0
• GWP: 1,430
• Boiling Point: -15.1°F (-26.1°C)
• Pressure at 70°F: ~70.2 psig
• Status: Subject to AIM Act phasedown; being replaced in new equipment
• Applications: Medium-pressure chillers, automotive AC (pre-R-1234yf), commercial refrigeration
• Key Fact: Medium-pressure refrigerant; widely used but being replaced by lower-GWP alternatives

R-410A — HFC Blend (Near-Azeotropic)

• Category: HFC blend (R-32/R-125, 50/50)
• ASHRAE Safety: A1
• ODP: 0
• GWP: 2,088
• Boiling Point: -60.8°F (-51.6°C)
• Pressure at 70°F: ~201 psig
• Status: Cannot be used in new residential/commercial AC (GWP exceeds 700 limit). Existing systems can continue to be serviced
• Applications: Residential/commercial AC, heat pumps (existing systems)
• Key Fact: Operates at approximately 60% higher pressures than R-22. Near-azeotropic — can be charged as liquid or vapor, but should be charged as liquid per manufacturer guidelines

R-404A — HFC Blend (Near-Azeotropic)

• Category: HFC blend (R-125/R-143a/R-134a)
• ASHRAE Safety: A1
• ODP: 0
• GWP: 3,922
• Boiling Point: -51.0°F (-46.1°C)
• Pressure at 70°F: ~175 psig
• Status: Primary target for phasedown due to extremely high GWP
• Applications: Commercial refrigeration, supermarkets, transport refrigeration (existing systems)
• Key Fact: Has one of the highest GWPs of any commonly used HFC; major phasedown target

R-407C — HFC Blend (Zeotropic)

• Category: HFC blend (R-32/R-125/R-134a)
• ASHRAE Safety: A1
• ODP: 0
• GWP: 1,774
• Boiling Point: -46.4°F (-43.6°C)
• Pressure at 70°F: ~133 psig
• Status: Subject to AIM Act phasedown
• Applications: Retrofit replacement for R-22 in some systems
• Key Fact: Zeotropic blend with significant temperature glide; must be charged as liquid only

Pressure-Temperature Reference (at 70°F / 21°C)

For the Exam: Know which refrigerants are high-pressure vs. low-pressure. R-410A operates at the highest pressures. R-11 and R-123 are low-pressure refrigerants that operate below atmospheric pressure (in vacuum). R-134a is considered medium-pressure.