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Refrigerant Designation Decoder

Type a common R-number and read the ASHRAE designation pattern, then review local property rows, GWP-basis caveats, safety-class notes, and source boundaries.

Refrigerant numbers are not arbitrary labels. For a single compound the digits count the carbon, hydrogen, and fluorine atoms in the molecule, which is how R-22 reads as one chlorine, one hydrogen, two fluorines (an HCFC) and R-32 reads as an HFC. For blends, a 400-series number is zeotropic and a 500-series number is azeotropic, with a trailing letter that distinguishes composition rows. The 700 series uses the molar mass cue, so 744 is CO2. This decoder reads those rules and, for common refrigerants, adds local source-gap rows for safety class, ODP, GWP, glide, and transition context. Verify those rows against current ASHRAE 34, SDS/product data, EPA SNAP/Section 608, program GWP basis, and equipment documentation before regulated or safety use.

Pro Tip: The safety class is two parts. The letter is toxicity (A is lower, B is higher) and the number is flammability (1 is no flame propagation, 2L is lower flammability, 3 is higher flammability). R-32 and R-454B are A2L in the local rows, which means they are not drop-in substitutes for A1 equipment. Listed equipment, charge limits, leak detection, ventilation, tools, labels, code, AHJ, and manufacturer rules control use.

Once you know the refrigerant, look up saturation pressure-temperature on the

Refrigerant P-T Chart →

Check the charge with superheat and subcooling using the

Superheat / Subcooling Calculator →

Estimate additional line-set charge with the

Refrigerant Charge Worksheet →

Estimate the CO2-equivalent of a leak from the selected GWP basis with the

Refrigerant Leak CO2 Equivalent Calculator →

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Refrigerant Designation Decoder
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How It Works

  1. Enter the R-number

    Type the designation from the nameplate or cylinder (R-410A, R-32, R-1234yf). Shorthand like CO2 works too.

  2. Read the number breakdown

    The decoder shows how the digits resolve under the ASHRAE 34 rules: the atom counts for a compound, or the blend series and composition letter for a blend.

  3. Check the local property rows

    For common refrigerants you get source-gap display rows for family, composition, safety class, ODP, GWP, and glide. These are prompts, not current standard-table certification.

  4. Read the source warnings

    Notes cover zeotrope fractionation, A2L/A3 flammability, CO2 pressure, high-GWP phase-down context, and where SDS, EPA, code, AHJ, and manufacturer review control.

  5. Verify before a regulated decision

    Confirm GWP basis, safety class, blend composition, SNAP/end-use status, Section 608 duties, and equipment compatibility against current sources before safety or compliance use.

Built For

  • An HVAC tech who finds an unfamiliar R-number on a nameplate and needs the safety class and pressure behavior before connecting gauges.
  • A contractor reviewing an R-22 nameplate before pulling current retrofit, SDS, SNAP, and manufacturer documents.
  • A facility manager flagging which GWP basis must be checked before CO2e or reporting work.
  • An apprentice learning why R-454B is mildly flammable but R-410A is not.
  • Anyone confused by why R-410A and R-32 have such different numbers despite both being used in AC.

Features & Capabilities

Parses common R-number patterns

The designation rules resolve atom-count or blend-series prompts even when detailed property rows are not in the local dataset.

Safety class broken out

The class is split into toxicity (A/B) and flammability (1/2L/2/3) with plain-English meaning.

Visible source boundaries

GWP, ODP, and composition rows are labeled as local source-gap values so cross-tool consistency does not look like regulatory approval.

Transition and phasedown context

For common refrigerants the tool shows local transition notes and HFC phasedown prompts without approving a substitute, retrofit, or purchase decision.

Comparison

R-number Family Safety class GWP Glide Note
R-22 HCFC A1 1810 None Legacy; production phased out 2020
R-410A HFC blend A1 2088 Negligible Residential AC; being phased down
R-32 HFC A2L 675 None Low-GWP A2L, mildly flammable
R-454B HFO/HFC blend A2L 466 ~1 F R-410A replacement, A2L
R-1234yf HFO A2L 1 None Automotive R-134a replacement
R-744 Inorganic (CO2) A1 1 None Natural; very high pressure

References

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Frequently Asked Questions

R-410A is a near-azeotropic HFC blend of R-32 and R-125 in a 50/50 local display row. The 4 marks it as a blend (400 series), and the trailing A identifies a composition row among blends of those components. It is listed locally as A1 with zero ODP and a 100-year GWP display value around 2088. Do not use this page to approve a retrofit to R-454B, R-32, or any other refrigerant; equipment listing, manufacturer data, SDS, EPA rules, code, and AHJ review control.
For a single compound, the ones digit is the number of fluorine atoms, the tens digit is the number of hydrogen atoms plus one, and the hundreds digit is the number of carbon atoms minus one (omitted when zero). Chlorine fills whatever bonds are left. So R-134a is two carbons, two hydrogens, four fluorines, no chlorine, which makes it an HFC. R-22 works out to one carbon, one hydrogen, two fluorines, one chlorine, which makes it an HCFC.
The letter is toxicity and the number is flammability. A is lower toxicity, B is higher toxicity. 1 means no flame propagation (non-flammable), 2L means mildly flammable with a low burning velocity, 2 means flammable, and 3 means highly flammable. So A2L (R-32, R-454B) is lower toxicity and mildly flammable, while A3 (propane, R-290) is lower toxicity but highly flammable.
A zeotropic blend boils and condenses over a range of temperatures rather than at one point, which is the glide. The components can fractionate after vapor transfer or leakage, so service procedure must come from the SDS, product data, manufacturer instructions, EPA rules, and qualified HVAC review. This page does not provide a charging or leak-response procedure.
GWP (Global Warming Potential) compares a gas to CO2 over a selected time horizon, often 100 years. High-GWP HFCs are affected by AIM Act phasedown and sector rules, but the correct number depends on the required AR4/AR5/AR6/product/program basis. Confirm the current basis before emissions reporting, procurement, permits, or transition planning.
Disclaimer: Properties, safety classifications, GWP values, ODP values, glide notes, and transition context returned by this decoder are reference prompts and vary by source, blend formulation, standard edition, reporting basis, end use, and equipment. Refrigerant handling is regulated, and A2L/A3 refrigerants require equipment, charge-limit, ventilation, leak-detection, tool, label, code, AHJ, and manufacturer review. Use this page to understand a designation, not to select, substitute, charge, recover, report, or approve a system; verify against current ASHRAE 34, EPA SNAP/Section 608, SDS/product data, manufacturer instructions, and applicable codes. This tool is educational/reference only and is not a substitute for an EPA-certified technician or qualified HVAC/environmental/legal review.

Learn More

HVAC

Refrigerant Numbers Explained

How the R-number system works, plus where local GWP, ODP, glide, safety-class, SNAP, SDS, and equipment-review limits apply.

Read Guide →

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