Refrigerant glossary
Chemistry and properties
GWP (Global Warming Potential)
How much heat a gas traps over a set horizon, usually 100 years, relative to the same mass of carbon dioxide. R-410A is 2,088 on the IPCC AR4 basis. Frameworks differ on whether they use AR4 or AR5 values. More.
ODP (Ozone Depletion Potential)
A gas's capacity to destroy stratospheric ozone, relative to R-11 at 1.0. R-22 is 0.055; HFCs contain no chlorine and are zero. More.
CFC
Chlorofluorocarbon. The first generation of synthetic refrigerants, high ODP, phased out under the Montreal Protocol. More.
HCFC
Hydrochlorofluorocarbon, such as R-22. Contains chlorine, so has an ODP, and is being phased out under the Montreal Protocol. More.
HFC
Hydrofluorocarbon, such as R-32, R-410A, R-134a and R-404A. Zero ODP but significant GWP, which is what the Kigali Amendment addresses. More.
HFO
Hydrofluoro-olefin. A newer family with very low GWP because the molecules break down quickly in the atmosphere. More.
Azeotrope
A blend that behaves as a single substance, boiling and condensing at one temperature for a given pressure, with no glide. More.
Zeotrope
A blend whose components boil at different temperatures, so it has temperature glide and can change composition if it leaks or is charged as vapour. More.
Temperature glide
The spread between a zeotropic blend's bubble point and dew point at one pressure. Superheat is read from dew point, subcooling from bubble point. More.
Fractionation
The change in a blend's composition when its lighter components escape first, typically through a leak or by charging as vapour. More.
LFL (Lower Flammability Limit)
The lowest concentration in air at which a gas will ignite. It sets the charge limits that apply to mildly flammable A2L refrigerants. More.
Indian regulation
ODS Rules, 2000
India's Ozone Depleting Substances (Regulation and Control) Rules, made under the Environment (Protection) Act, governing production, import, sale, purchase and reclamation of ozone-depleting substances. More.
ODS seller registration
The registration a seller of ozone-depleting substances such as R-22 must hold. Ours is ODS/CS/17/6(12)/2024-OC, dated 12.11.2024. More.
Rule 7 buyer declaration
A purchaser buying an ozone-depleting substance for stock or a regulated activity must give the seller a declaration under Part I of Schedule XII; the seller verifies it under Part II. More.
Ozone Cell
The unit within the Ministry of Environment, Forest and Climate Change that administers India's Montreal Protocol obligations, including ODS registrations. More.
HPMP
HCFC Phase-out Management Plan — the programme through which India implements its HCFC reduction steps, now in its third stage. More.
Montreal Protocol
The 1987 treaty controlling ozone-depleting substances, the framework under which R-22 is being phased out. More.
Kigali Amendment
The 2016 amendment to the Montreal Protocol adding HFCs. India freezes HFC consumption at 2024 levels with reductions from 2028. More.
PESO
The Petroleum and Explosives Safety Organisation, which administers the Gas Cylinders Rules governing compressed-gas cylinders in India. More.
Gas Cylinders Rules, 2016
The rules governing filling, storage, transport and testing of compressed-gas cylinders, including refrigerant cylinders. More.
Form F
A PESO licence to store filled compressed-gas cylinders above the Rule 44 exemption threshold, applied for in Form C. More.
Anti-dumping duty
A customs duty imposed where goods are found to be exported below normal value and injuring domestic industry. One applies to R-134a imported from China. More.
Service and practice
Superheat
The temperature of refrigerant vapour above its saturation temperature at that pressure. On a glide blend, read it from the dew point. More.
Subcooling
The temperature of liquid refrigerant below its saturation temperature at that pressure. On a glide blend, read it from the bubble point. More.
Evacuation
Removing air and moisture from a system with a vacuum pump before charging. Air raises head pressure permanently; moisture forms acids. More.
Triple evacuation
Evacuating, breaking the vacuum with dry nitrogen and repeating, conventionally three times. Each nitrogen break sweeps out moisture the previous pull could not remove. More.
Non-condensables
Gases such as air that do not condense in the condenser. They occupy volume and raise head pressure for the life of the system. More.
Standing-pressure test
Pressurising a system with dry nitrogen and leaving it isolated with a gauge to establish whether it leaks, before hunting for where. More.
Recovery
Removing refrigerant from a system and storing it in an approved container, without necessarily cleaning it. More.
Recycling
Basic on-site clean-up of recovered refrigerant, typically for return to the same system. It does not meet resale purity requirements. More.
Reclamation
Reprocessing recovered refrigerant back to virgin specification, verified by analysis, by a qualified processor. A separately regulated activity in India. More.
POE oil
Polyol ester lubricant, required by HFC systems. It is hygroscopic, so it absorbs moisture readily and demands better evacuation discipline than mineral oil did. More.
Compressor burnout
Failure of the motor windings, which produces acid and debris that contaminates the entire circuit, not just the compressor. More.
Retrofit
Converting a system to a different refrigerant. It involves recovery, an oil change, a new drier and usually expansion-device changes — never a simple top-up. More.
Standards, safety and documents
ASHRAE 34
The standard that assigns refrigerant numbers and safety classifications, from A1 (non-flammable, low toxicity) through A2L to A3 and the B series. More.
A1
Safety class for refrigerants of low toxicity that show no flame propagation, such as R-22, R-410A, R-134a, R-404A and R-407C. More.
A2L
Safety class for mildly flammable, low-toxicity refrigerants with a low burning velocity, such as R-32. More.
AHRI Standard 700
The standard setting maximum contaminant limits — moisture, non-condensables, high-boiling residue, particulates and acidity — for acceptable refrigerant purity. More.
SDS (Safety Data Sheet)
The standardised document describing a product's hazards, handling, storage and emergency measures. Buyers should hold a current, product-specific one. More.
Batch traceability
The ability to tie a specific cylinder back to a production batch and forward to your invoice — the basis of an audit trail and of counterfeit detection. More.
Scope 1 emissions
Direct greenhouse-gas emissions from sources an organisation owns or controls. Refrigerant that leaks from your equipment falls here. More.
BRSR
The Business Responsibility and Sustainability Report that listed Indian entities file. Refrigerant leakage surfaces under its environmental principle. More.
Counterfeit refrigerant
Gas sold as one product that is something else, often adulterated. Contamination with R-40 (methyl chloride) has caused documented injuries and equipment destruction. More.
Quick answers
What is the difference between recovery, recycling and reclamation?
Recovery means removing refrigerant from a system and storing it. Recycling means basic on-site clean-up, usually for return to the same system. Reclamation means reprocessing it back to virgin specification, verified by analysis, by a qualified processor — a separately regulated activity.
What does A2L mean?
It is an ASHRAE 34 safety classification for refrigerants of low toxicity that are mildly flammable with a low burning velocity. R-32 is the A2L most commonly encountered in India.
What is temperature glide?
The temperature spread between a zeotropic blend's bubble point and dew point at a given pressure. It matters in service because superheat must be read from the dew point and subcooling from the bubble point.
- ASHRAE — Standard 34 refrigerant designations and safety classifications — ashrae.org.
- Ozone Cell, MoEFCC — ODS Rules, 2000 and India's Montreal Protocol and Kigali Amendment obligations — ozonecell.nic.in.
- Petroleum and Explosives Safety Organisation — Gas Cylinders Rules, 2016 — peso.gov.in.
- AHRI — Standard 700 refrigerant purity specification — ahrinet.org.
This guide is general information compiled from the cited sources — not legal, safety or engineering advice. Read our full disclaimer.
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