R170 RefrigerantEthane · natural hydrocarbon · very low temperature and cascade refrigeration
R170 is refrigerant-grade ethane, a natural hydrocarbon with excellent low-temperature characteristics. Its strongest refrigeration role is in very low temperature and cascade systems where conventional refrigerants cannot easily deliver the required temperature range. With zero ODP and low direct GWP, it is environmentally attractive, but its A3 higher-flammability classification requires disciplined system design and hydrocarbon-specific safety practice.
What is R170 refrigerant?
R170 is not a mainstream supermarket or split-AC refrigerant. Its importance lies in specialized low-temperature work: laboratory freezers, cascade refrigeration, cryogenic-adjacent cooling and industrial low-temperature systems. That makes it an excellent knowledge page because searchers usually need technical clarity, not generic introductory copy.
R170 refrigerant properties
Use these values for research and screening. For equipment design, charging and compliance, use the exact supplier PT data, SDS, OEM documentation and regulation that governs the project.
| Property | Reference | Engineering / source note |
|---|---|---|
| Designation | R170 | ASHRAE designation for ethane |
| Chemical name | Ethane | Natural hydrocarbon |
| Formula | C₂H₆ | NIST / industrial gas data |
| Molecular weight | 30.069 g/mol | Industrial gas data |
| Normal boiling point | ≈ −88.6°C | Industrial gas data |
| ODP | 0 | No ozone depletion |
| 100-year GWP | 5.5 | EPA Technology Transitions |
| Safety classification | A3 | Higher flammability |
| Temperature glide | None | Pure compound |
| Primary role | Very low temperature refrigeration | Cascade / laboratory / industrial niche |
EPA Technology Transitions uses the values shown on this page. Older product literature may use IPCC AR4/AR5 or another assessment, so a different number is not automatically an error.
Where is R170 used?
Applications must be evaluated by system type, charge, compressor, heat exchanger, safety class and current regulation. The examples below describe recognized use contexts, not automatic approval for every installation.
Very low temperature refrigeration
EPA has a dedicated SNAP category for this end use.
Cascade systems
Frequently used on the low-temperature stage.
Laboratory freezers
Relevant in very low temperature equipment subject to use conditions.
Industrial low-temperature process cooling
Useful where very low evaporating temperatures are required.
Cryogenic-adjacent refrigeration systems
Suitable in certain engineered low-temperature duties.
Natural refrigerant research
Important reference fluid in ultra-low-temperature natural refrigerant discussions.
Continue through the Refrigerant Replacements and Low-GWP Refrigerants hubs for broader selection context.
Why R170 belongs in a refrigerant database even if the market is smaller
Very low temperature refrigeration is a distinct technical segment with different priorities than normal HVAC or supermarket refrigeration.
R170 is one of the refrigerants that really matters in that segment because of its extremely low boiling point and ability to support very low evaporating temperatures.
Adding R170 expands refrigerants.net from general-purpose refrigerant education into specialist low-temperature knowledge.
R170 vs R1150: both are very low temperature hydrocarbons, but not the same job
R170 is ethane; R1150 is ethylene. Both are A3 hydrocarbons used in very low temperature work, but their thermophysical characteristics and ultimate temperature ranges differ.
In content strategy, the value comes from explaining when readers typically encounter one versus the other, rather than pretending all ultra-low-temperature hydrocarbons are interchangeable.
This helps your site become more useful to higher-intent technical readers.
Why A3 safety dominates the design conversation
At the temperatures where R170 is attractive, system architecture can already be complex. Adding a higher-flammability refrigerant means ventilation, ignition source control, component suitability and leak risk management become central design issues.
The same very low boiling point that makes R170 powerful for low-temperature duty also shapes release behavior and detector strategy.
Any high-quality page on R170 should therefore discuss safety in engineering terms, not only as a warning label.
EPA SNAP context: specialized use, not blanket permission
EPA has a dedicated SNAP category for very low temperature refrigeration, which is the right regulatory lens for R170.
This is important because the refrigerant should not be generalized into broader end uses without checking the exact listing and any use conditions or narrowed use limits.
That end-use-specific logic is exactly the kind of nuance AI search systems often miss unless the page explains it clearly.
R170 vs R1150
The table highlights engineering differences rather than implying direct interchangeability.
| Characteristic | R170 | R1150 |
|---|---|---|
| Chemical | Ethane (C2H6) | Ethylene (C2H4) |
| EPA GWP | 5.5 | 3.7 |
| Safety class | A3 | A3 |
| Boiling point | ≈ −88.6°C | ≈ −103.7°C |
| Typical role | Very low temperature / cascade | Even deeper low-temperature stage / ultra-low range |
| Phase behavior | Pure | Pure |
| Content value | Specialized VLT knowledge | Specialized VLT knowledge |
R170 safety: the A3 classification is central to system design
R170 is A3. Safe use depends on limiting flammable mixture formation, controlling ignition sources, providing ventilation and using equipment specifically suited for hydrocarbon refrigerants. In very low temperature systems, release behavior and enclosure design deserve particular attention.
A3 hydrocarbon
Higher flammability requires disciplined engineering controls.
Low-temperature release behavior
Cold gas behavior and ventilation patterns should be considered.
Specialist equipment
Use components and procedures suited to hydrocarbon refrigerants.
Actual risk depends on charge, release rate, pressure, room volume, ventilation, ignition sources, equipment construction, alarm logic and service condition.
See the Refrigerant Safety Guide for classification context.
R170 refrigerant leak detection
Validate detector response to the finished blend
R170 leak detection should use hydrocarbon combustible-gas detection validated for ethane. Fixed monitoring, alarm thresholds and detector placement should be determined by the risk assessment and applicable standards. Portable leak checking and fixed mitigation monitoring are different tools with different performance targets.
Portable service leak detectors, fixed area monitors, A2L mitigation sensors and refrigerant identifiers perform different functions. Define the alarm action and concentration range before selecting the technology.
Regulatory position of R170 in 2026
United States
EPA Technology Transitions uses GWP 5.5 for R170. EPA’s SNAP framework addresses R170 primarily through the very low temperature refrigeration end use, including use conditions and narrowed use limits where applicable. That specialized end-use framing is the correct way to discuss R170 in compliance terms.
European Union
As a natural hydrocarbon, R170 is not part of the HFC phasedown quota system. In Europe, the major constraints are safety standards, machinery design, hazardous-area considerations where relevant and application-specific equipment rules.
Is R170 being phased out?
R170 is not being phased out for climate reasons. Its practical limits come from safety, system complexity and the specialized nature of very low temperature applications.
U.S. refrigeration limits differ by cold storage, supermarket, remote condensing, stand-alone product, industrial process and chiller category. A refrigerant may fit one pathway and fail another.
Use the Refrigerant Regulations Hub for regional research.
What should be compared with R170?
Compare the real equipment pathway: retrofit vs new system, A1 vs A2L capability, GWP threshold, glide, compressor envelope, energy efficiency and service ecosystem.
Practical misconceptions about R170
“R170 is just another everyday refrigerator gas.”
Its main role is specialized very low temperature refrigeration.
“Low GWP means no safety concern.”
R170 is A3 and flammability is a central engineering issue.
“Any hydrocarbon detector is equally suitable.”
Detector performance must be validated for ethane and the intended concentration range.
“R170 and R1150 are basically the same.”
They are different molecules with different boiling points and application ranges.
R170 refrigerant FAQ
Concise answers to common composition, retrofit, glide, safety and regulation questions.
What is R170?
What is the EPA GWP of R170?
Is R170 flammable?
What is R170 used for?
Is R170 a blend?
What is the boiling point of R170?
Why is R170 important?
Is R170 widely used in normal HVAC?
How should R170 leaks be detected?
Is R170 being phased out?
R170 sources and further reading
This profile uses current EPA regulatory references plus refrigerant supplier, NIST, scientific and GasNose resources. Re-check the latest edition before design or compliance decisions.
Working with R170 or planning a refrigerant transition?
Compare GWP, safety class, temperature glide, equipment compatibility and regulatory lifetime before selecting a refrigerant.
Technical Notice: This page is for refrigerant research and general technical reference. Refrigerant suitability, permitted charge, equipment approval, leak mitigation, servicing procedures and regulatory compliance depend on the exact equipment, installation and jurisdiction. Always verify current manufacturer documentation, SDS, applicable standards and local regulations before selecting, replacing, charging or servicing a refrigerant.