R-290
R-290 is refrigerant-grade propane. With a GWP of 3.3 it passes every federal GWP limit, including the 150 limits that arrive for large systems on January 1, 2032 (91 FR 31284)[2]. It is one of the three long-term paths for commercial refrigeration, next to CO2 and the A2L blends.
The tradeoff is flammability. R-290 is ASHRAE class A3, so it appears in self-contained, charge-limited equipment rather than large field-piped systems. Charge limits come from EPA SNAP use conditions and the equipment safety standard[4].
R-290 quick facts
| Type | Natural refrigerant: refrigerant-grade propane, single compound |
| ASHRAE safety class | A3 (higher flammability) |
| GWP (AIM Act exchange values) | 3.3 |
| Temperature glide | None (single compound) |
| Lubricant | Mineral oil or POE per equipment listing |
| Common use | Self-contained commercial refrigeration: reach-ins, display cases, small monoblocks |
Regulatory status
| Buying R-290 | No Section 608 restriction, as an exempt substitute in its listed end-uses[3] |
| New equipment, any GWP-limited subsector | Qualifies (GWP 3.3 is under every limit)[2] |
| Charge per circuit | Capped by SNAP use conditions and UL 60335-2-89 listing[4] |
| Venting | Exempt from the venting prohibition in listed end-uses[4] |
Rules
Federal
R-290 is under every GWP limit in the Technology Transitions rule, so the compliance dates that end high-GWP installs are entry points for R-290 equipment[2]. The binding federal constraints are the SNAP use conditions instead: listed end-uses, charge limits, and marking requirements (89 FR 50410)[4].
| Subsector | Limit | Date | R-290 outcome |
|---|---|---|---|
| Retail food refrigeration (self-contained) | SNAP-listed end-use | Current[4] | Charge cap per SNAP use conditions and UL 60335-2-89 |
| Supermarket systems, remote condensing units, cold storage | GWP 150/300 from Jan 1, 2032 | Jan 1, 2032[2] | R-290 qualifies, and the equipment listing governs where it can be used |
State
No state HFC rule restricts R-290, since state HFC programs target high-GWP substances. Building and mechanical codes govern flammable refrigerants, and adoption varies by jurisdiction. Verify with your local authority having jurisdiction before an install decision.
Buying R-290
R-290 is an exempt substitute under 40 CFR 82.154 in its listed end-uses, so the Section 608 sales restriction does not apply to it[3]. Sellers may still require credentials as store policy. Refrigerant-grade propane (higher purity, moisture-controlled) is not the same product as grill propane. Equipment warranties and listings specify refrigerant grade.
Safety and handling
A3 means higher flammability. R-290 belongs only in equipment designed and listed for it, with charge limits, spark-free components, and marked circuits. Never charge R-290 into a system built for an A1 refrigerant. Service work follows the manufacturer's procedures for flammable refrigerants, including ventilation and leak checks with tools rated for A3 service.
Replacements
R-290 is a destination, not a refrigerant that gets replaced. For loads too large for its charge limits, the low-GWP paths are CO2 for racks and large systems, and A2L blends such as R-454C and R-455A for field-piped equipment under the 2032 limits[2].
R-290 PT chart
Saturation pressures for R-290 from -40 °F to 150 °F, computed from reference equations of state[5]. Propane is a single compound, so liquid and vapor pressures are equal at a given temperature and there is no glide.
| Temp (°F) | Liquid / bubble (psig) | Vapor / dew (psig) |
|---|---|---|
| -40 | 1.4 | 1.4 |
| -35 | 3.4 | 3.4 |
| -30 | 5.7 | 5.7 |
| -25 | 8.1 | 8.1 |
| -20 | 10.7 | 10.7 |
| -15 | 13.6 | 13.6 |
| -10 | 16.7 | 16.7 |
| -5 | 20.1 | 20.1 |
| 0 | 23.7 | 23.7 |
| 5 | 27.6 | 27.6 |
| 10 | 31.8 | 31.8 |
| 15 | 36.3 | 36.3 |
| 20 | 41.1 | 41.1 |
| 25 | 46.3 | 46.3 |
| 30 | 51.8 | 51.8 |
| 35 | 57.7 | 57.7 |
| 40 | 63.9 | 63.9 |
| 45 | 70.6 | 70.6 |
| 50 | 77.6 | 77.6 |
| 55 | 85.1 | 85.1 |
| 60 | 93.0 | 93.0 |
| 65 | 101.4 | 101.4 |
| 70 | 110.2 | 110.2 |
| 75 | 119.5 | 119.5 |
| 80 | 129.3 | 129.3 |
| 85 | 139.7 | 139.7 |
| 90 | 150.5 | 150.5 |
| 95 | 161.9 | 161.9 |
| 100 | 173.9 | 173.9 |
| 105 | 186.5 | 186.5 |
| 110 | 199.6 | 199.6 |
| 115 | 213.4 | 213.4 |
| 120 | 227.8 | 227.8 |
| 125 | 242.9 | 242.9 |
| 130 | 258.7 | 258.7 |
| 135 | 275.1 | 275.1 |
| 140 | 292.3 | 292.3 |
| 145 | 310.2 | 310.2 |
| 150 | 328.9 | 328.9 |
Use the vapor (dew) column to check superheat at the suction line. Use the liquid (bubble) column to check subcooling at the liquid line and for charging. R-290 has no glide, so one pressure column serves both charging and superheat checks. R-290 values are computed, not transcribed; see Sources.
Equipment rated for R-290
No walk-in unit cooler rates R-290 today, because the walk-in lines use A2L blends and CO2 for their low-GWP options. R-290 equipment in this market is mostly self-contained, and those models will be listed as their documentation is added.
Questions
- Do I need a 608 certification to buy R-290?
No federal certification is required, because R-290 is an exempt substitute under 40 CFR 82.154 in its listed end-uses. Sellers may set their own policies. Handling it still requires training for flammable refrigerants.
- Can I retrofit an R-404A system to R-290?
No. R-290 is A3 flammable and belongs only in equipment designed, listed, and marked for it. Retrofitting a non-listed system with propane violates the equipment listing and creates a fire hazard.
- Is R-290 legal in walk-in coolers?
Federal GWP limits do not restrict it, and SNAP lists R-290 for specified end-uses with charge caps (89 FR 50410). Whether a given walk-in can use it depends on the equipment listing and local codes. Most walk-in unit cooler lines use A2L blends or CO2 instead.
- Why is the R-290 charge limited?
Flammability. SNAP use conditions and UL 60335-2-89 cap the charge per circuit so a leak cannot form an ignitable volume in the space. Larger loads use multiple circuits or a different refrigerant.
References
- ^1.40 CFR part 84, Appendix A: GWP exchange values (eCFR)
- ^2.91 FR 31284 (May 26, 2026): Technology Transitions reconsideration final rule
- ^3.40 CFR 82.154: refrigerant sales restriction and venting exemptions (eCFR)
- ^4.89 FR 50410 (Jun 13, 2024): SNAP Rule 26 listings, including R-290 charge limits and venting exemption
- ^5.CoolProp 8.0 mixture models (Bell et al. 2014, doi:10.1021/ie4033999)
Updated