RS-100 (R464A)

Lowest non-flammable GWP replacement for R404A & R507

No change of lubricant or equipment required

ASHRAE A1 safety classification

RS-100 is a new addition to the RS range of specialist refrigerants. RS-100 is non-flammable with the lowest Global Warming Potential (GWP) of the non-flammable HFO/HFC blends on the market. RS-100 has been designed to match the thermodynamic properties of R404A and R507 with similar cooling capacity, Coefficient of Performance & operating pressures. RS-100 can, therefore, replace R404A & R507 across the temperature range where the latter are commonly found.

RS-100 is miscible with the polyol ester lubricants used with R404A and R507, so there is no need to change the oil when retrofitting to RS-100.

RS-100 has a powerful combination of properties to replace R404A & R507 including, critically, cost as well as low environmental impact. This has not been achieved at the expense of performance, which is superior to R404A. Retrofitting R404A & R507 with RS-100 is a simple & straightforward process with few changes needed. The GWP of RS-100 is 67% lower than R404A, which is particularly important in regions where regulations are being increasingly introduced that target the dramatic reduction of R404A, e.g. the European Union where there is no future for the continued use of these high GWP refrigerants.

Performance Characteristics

  • Lowest direct non-flammable GWP HFO/HFC replacement for R404A and R507 on the market
  • Similar energy efficiency to R404A
  • Close match for R404A in cooling capacity
  • Lower discharge pressure than R404A
  • No changes to hardware required during retrofitting with only adjustment of the expansion device needed
  • Compatible with existing POE lubricants
  • Replaces R404A in refrigeration applications
  • Lower flow rate than R404A
  • Simple & straightforward retrofit procedure to replace R404 and & R507
  • Zero Ozone Depletion Potential
  • Non-flammable & low toxicity

Low Global Warming Potential

The whole subject of global warming and climatic change has become arguably one of the most important environmental issues of the day. Much research has been conducted on an international basis culminating in the recent report of the Inter-Governmental Panel on Climate change, which concludes that there is overwhelming evidence of warming of the planet caused by man-made activities.

Global Warming Potentials

Increasing quantities of carbon dioxide are considered as the prime cause of global warming taking place, and the Authorities are increasingly minded to restrict the emissions of materials with a significant GWP and in particular R404A and R507, which are at the high end of the global warming scale.

The recent IPCC report indicates that HFCs would contribute less than 2% to global warming, far less than the effects of carbon dioxide emitted by fossil combustion and deforestation. HFC refrigerants underpin present refrigeration and air-conditioning technologies giving customers an excellent combination of high efficiency with low hazard. Nevertheless, governments are minded to increasingly restrict HFC emissions by regulation and/or taxation, e.g. revision of the F Gas regulation in the European Union in 2022, EPA’s final rule in the USA, Kigali amendment to the Montreal Protocol.


Coefficient of Performance

Discharge pressure

RS-100 has similar energy efficiency, cooling capacity and discharge pressure as R404A. RS-100 is also used with the same lubricants as R404A so there is no necessity to change the oil during a retrofit. RS-100 is suitable for use in many of the applications where R404A is commonly found, including supermarket display cases, cold stores, freezers, ice machines, beer cellars, freezer cabinets, freeze dryers and environmental test chambers.


RS-100 has an A1 safety classification, which is non-flammable, low toxicity and has been assigned an ASHRAE number of R464A. The components of RS-100 have been subjected to toxicity tests carried out by the Alternative Fluorocarbons Environmental Acceptability Study (AFEAS).


RS-100 is used with polyol ester lubricants, the same lubricants that are used with R404A and R507, so that there is no need to change the oil when converting from R404A to RS-100.


Because RS-100 is a blend, it should be charged into the system in the liquid as opposed to vapour form. There is no need to make any hardware changes when converting from R404A to RS-100 other than adjusting the expansion device to reflect its lower flow rate than R404A.

Technical Data

Technical data including thermodynamic tables, physical properties, retrofit guide, materials of compatibility, questions and answers etc are available on the web site.

RS-100 Pressure Enthalpy Chart

RS-100 Physical Properties

    RS-100(2) R404A(2)
Molecular Mass kg/kgmole 88.3 97.6
Boiling point (1 atm)(1) °C -46.5 -46.2
°F -51.7 -51.2
Temperature glide(4) K 4 0.5
Critical temperature °C 88.6 72.1
°F 108.7 161.7
Critical pressure bara 45.0 37.29
psia 653 541
Liquid density (25°C)(1) kg/m³ 1095 1044
Density of saturated vapour (25°C)(1) kg/m³ 52.231 65.27
Latent Heat of Vaporisation at boiling point(3) kJ/kg 256.97 199.6
Cv (25°C)(1) kJ/kg.K 0.74684 0.7844
Cp (25°C & 1bara) kJ/kg.K 0.8492 0.8771
Cp/Cv (25°C & 1bara)   1.1371 1.118
Vapour Pressure (25°C)(1) bara 12.88 12.55
psia 186.8 182.0
Vapour Viscosity (25°C & 1bara) cP 0.0131 0.0120
Liquid Viscosity (25°C)(1) cP 0.138 0.128
Liquid Thermal Conductivity (25°C) W/m.K 0.809 0.0636
Surface Tension (25°C)(1) N/m 0.00791 0.00455
Specific heat of liquid (25°C)(1) kJ/kg.K 1.541 1.541
Ozone Depletion Potential ODP 0 0
Flammability limit in air (1 atm) vol% none none
Inhalation exposure (8 hour day & 40 hour week) ppm 1000 1000
Global Warming Potential GWP 1321 3922

(1) Bubble Point.
(2) RS-100 and R404A refrigerant properties obtained from NIST's REFPROP program.
(3) Difference between bubble point liquid enthalpy and dew point vapour enthalpy at the same pressure.
(4) Pressure drop of 0.12 psi in evaporator.