Refrigerant Knowledge Center
What Is R502 Refrigerant? Properties, Uses and Safety
R502 is an ozone-depleting CFC/HCFC azeotropic blend formerly used for low-temperature refrigeration, now treated as a legacy refrigerant with replacement and recovery decisions tied to existing systems.
What Is R502?
R502 is an ozone-depleting CFC/HCFC azeotropic blend formerly used for low-temperature refrigeration, now treated as a legacy refrigerant with replacement and recovery decisions tied to existing systems.
R502 is classified as azeotropic blend in the CFC/HCFC blend family. Its composition is 48.8% R22 / 51.2% R115 by mass. Refrigerant choice is never based on designation alone: capacity, pressure, lubricant, controls, heat-exchanger behavior, safety standards and local rules all matter.
R502 Technical Properties
General reference values for comparison; a current product specification and applicable regulatory basis govern a transaction.
| Refrigerant designation | R502 |
|---|---|
| Chemical family | CFC/HCFC blend |
| Composition | 48.8% R22 / 51.2% R115 by mass |
| Blend type | azeotropic blend |
| ASHRAE safety class | A1 |
| 100-year GWP | 4657 (manufacturer-reported 100-year GWP) |
| Ozone depletion potential | 0.25 |
| Normal boiling reference | -45.6 °C |
Common R502 Applications
Typical references include legacy low-temperature commercial refrigeration, and legacy cold storage.
Use depends on equipment design, operating envelope and applicable local requirements.
Use depends on equipment design, operating envelope and applicable local requirements.
Advantages and Limitations
Selection advantages
- Established refrigerant designation with published reference data.
- Application history in legacy low-temperature commercial refrigeration.
- ODP reference of 0.25.
Important limitations
- A1 safety controls must be applied.
- GWP and lifecycle status can affect long-term selection.
- No refrigerant should be treated as a universal drop-in.
Environmental Impact and Regulation
This legacy blend is subject to ozone-depleting-substance phaseout controls; any remaining servicing pathway depends on local recovered-material rules.
R502 has an ODP reference of 0.25 and a stated GWP of 4657 using manufacturer-reported 100-year GWP. Regulations commonly distinguish between manufacturing or import, new equipment, servicing, recovered material and individual end uses.
Safety, Handling and Storage
Do not vent R502; recover the full charge and use a documented retrofit design that accounts for oil, controls, capacity, pressure and component compatibility.
The A1 classification describes toxicity and flammability groupings; it does not by itself approve a refrigerant for a particular system. Review the current safety data sheet, cylinder label, transport classification, equipment manual and local code.
R502 Alternatives and Comparisons
Candidate alternatives must be evaluated as system choices, not simple chemical substitutions.
HFC blend; A1 safety class; GWP 3922 on the stated IPCC AR4 100-year basis.
HFC blend; A1 safety class; GWP 3985 on the stated IPCC AR4 100-year basis.
HFO/HFC blend; A1 safety class; GWP 1273 on the stated IPCC AR5 100-year, manufacturer-reported basis.
HFO/HFC blend; A1 safety class; GWP 1282 on the stated IPCC AR5 100-year, manufacturer-reported basis.
natural refrigerant; A1 safety class; GWP 1 on the stated CO2 reference value, 100-year basis.
R502 Frequently Asked Questions
What is R502 made of?
48.8% R22 / 51.2% R115 by mass; it is categorized as azeotropic blend.
What is the safety class of R502?
The published classification used in this guide is A1. Equipment approval and local safety rules still apply.
What is the GWP of R502?
The reference here is 4657 on the manufacturer-reported 100-year GWP basis. Other assessment bases may show a different number.
Can R502 replace another refrigerant directly?
No universal drop-in claim is made. Compatibility and conversion requirements must be confirmed for the exact equipment.
Where is R502 commonly used?
Typical applications include legacy low-temperature commercial refrigeration, and legacy cold storage, subject to equipment design and local approval.
References and Technical Sources
Source data is summarized for general education. Always use current official documents, standards and supplier-specific safety and technical data for engineering or compliance decisions.
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