- Chlorofluorocarbon ("CFCs")
Chlorofluorocarbons1 (CFCs) are non-toxic, non-flammable chemicals containing atoms of carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F). Developed in the 1930s as safe alternatives to ammonia and sulfur dioxide, they became the primary cooling agents in refrigeration and air conditioning, as well as propellants in aerosol cans and blowing agents for foams.
While CFCs are stable and harmless at ground level, they do not break down until they reach the stratosphere. Once there, ultraviolet (UV) radiation breaks them apart, releasing chlorine atoms.
- Catalytic Destruction: A single chlorine atom can destroy upwards of 100,000 ozone O3 molecules before it is removed from the atmosphere.
- Atmospheric Longevity: CFCs have a long atmospheric lifespan (often 50 to 100 years), meaning the chemicals released decades ago are still impacting the ozone layer today.
Applications in Fire Safety
- Fire Extinguishing Agents: Some CFCs, such as CFC-11 and CFC-12, were occasionally used in specialised fire extinguishers. However, they were generally less effective than Halons at chemically "interrupting" a fire's chain reaction.
- Aerosol Propellants: CFCs were the industry standard for propellant used in aerosol fire extinguishers before they were banned.
- Total Flooding Systems: In some early industrial settings, CFC-based mixtures were used to "flood" a room to displace oxygen and suppress fire, though they required higher concentrations to be effective compared to Halon 1301.
CFCs were phased out of fire safety not because they were ineffective, but because their chemical stability—the very trait that made them "safe" for human use—allowed them to drift into the upper atmosphere intact, where they could catalyse the destruction of the ozone layer for decades.
CFCs were the primary target of the original 1987 Montreal Protocol.
Their phase-out led to the temporary use of Hydrochlorofluorocarbons (HCFCs) (which contain less chlorine) and eventually HFCs (which contain no chlorine), though the latter sparked the current debates regarding global warming potential.
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Wikipedia contributors 2024, ‘Chlorofluorocarbon’, Wikipedia, The Free Encyclopedia, viewed [May 1, 2026], https://en.wikipedia.org/wiki/Chlorofluorocarbon.