UPSC Prelims 2023 Q20: Uses of Hydrofluorocarbons (HFCs) — Explained

Consider the following:

1. Aerosols

2. Foam agents

3. Fire retardants

4. Lubricants

In the making of how many of the above are hydrofluorocarbons used?

Only one
Only two
Only three
All four

Answer: (c) Only three

Statement-wise explanation

1: correct — HFCs are used as propellants in aerosol products. HFC-134a and HFC-227ea are the main propellants in metered-dose inhalers used for asthma. UNEP lists aerosols as one of the main sectors that use HFCs, along with refrigeration, air-conditioning and foams.
2: correct — HFCs are used as blowing agents to make insulating foams such as polyurethane, polyisocyanurate, extruded polystyrene and phenolic foams. They replaced the CFC and HCFC blowing agents that were phased out under the Montreal Protocol.
3: correct — Some HFCs are 'clean agent' fire suppressants that replaced halons, which were phased out because they destroy ozone. HFC-227ea (sold as FM-200) is the most widely used, and HFC-125 is used in smaller amounts, for example in aircraft engine nacelles. UPSC's word 'fire retardants' refers to this fire-protection use.
4: incorrect — HFCs are gases or volatile liquids. They are not used to make lubricants. Recognised HFC sectors are refrigeration and air-conditioning, foams, aerosols, fire protection and solvents. The link to lubricants runs the other way: compressors that use HFC refrigerants need special oils such as polyolester (POE) oils.

How to eliminate

Absolute words do not help here, so you need the list of HFC applications. Use the history of the chemicals. HFCs were brought in to replace CFCs, HCFCs and halons wherever those were used. CFCs were used as refrigerants, aerosol propellants and foam-blowing agents, and halons as fire extinguishers. So aerosols, foams and fire suppression all follow from the CFC/halon story. Lubricants were never a CFC use, and a gas or volatile liquid is a poor base for a lubricant. That makes statement 4 the one to doubt. Fact to remember: HFC sectors = refrigeration/AC, foams, aerosols (including inhalers), fire protection, solvents. Lubricants are not on the list.

Know more

Hydrofluorocarbons (HFCs) contain only hydrogen, fluorine and carbon. They have no chlorine or bromine, so they do not deplete ozone (ODP = 0). They are strong greenhouse gases, though. PIB puts their global warming potential (GWP) at 12 to about 14,000.

The substitution chain

Generation	Example	Ozone-depleting?	GWP	Control
CFCs	CFC-11, CFC-12	High	Very high	Phased out under the Montreal Protocol (1987)
Halons	Halon-1301	Very high	High	Phased out under the Montreal Protocol
HCFCs	HCFC-22	Low	Moderate–high	Phase-out under way
HFCs	HFC-134a, HFC-227ea	None	High	Phase-down under the Kigali Amendment (2016)
HFOs / natural refrigerants	HFO-1234yf, ammonia, CO2, hydrocarbons	None	Very low	Preferred alternatives

Where HFCs are used: refrigeration and air-conditioning (the largest share), insulating foams, aerosols (including medical inhalers), fire protection and solvents.

Kigali Amendment. Parties agreed it at the 28th Meeting of the Parties in Kigali on 15 October 2016. It entered into force on 1 January 2019. It added HFCs to the Montreal Protocol even though they do not deplete ozone. It is a phase-down, not a phase-out. Countries are split into groups:

Developed countries: 2011–13 baseline; cuts began in 2019.
Most developing countries (Group 1): freeze in 2024.
India (Group 2): 2024–26 baseline, freeze in 2028, then cuts of 10% (2032), 20% (2037), 30% (2042) and 85% (2047).

India ratified the amendment in September 2021. Its India Cooling Action Plan (2019) aims to reduce cooling and refrigerant demand, which ties in with the HFC phase-down.

In the news

India ratified the Kigali Amendment in September 2021 and must freeze HFC consumption in 2028. HFC phase-down, cooling demand and World Ozone Day releases were in the news in 2021–2023, so a question on HFC applications was likely.

NCERT Concepts to Revise

Kigali Amendment: The Kigali Amendment is the treaty change that puts HFCs under control, which is why HFC applications became a Prelims topic.
Montreal Protocol: HFCs replaced the substances this treaty phased out, so their uses follow the old CFC and halon uses.
Global warming potential: High global warming potential is the reason HFCs are being phased down even though they are ozone-safe.
Chlorofluorocarbons: Knowing what CFCs were used for helps you work out which products later switched to HFCs.
Greenhouse gases: HFCs are classified as greenhouse gases, the core reason they are now regulated.
Ozone layer: HFCs contain no chlorine, so they do not harm the ozone layer; that is why they were chosen as substitutes.