Pentafluoroethane is a

fluorocarbon Fluorocarbons are chemical compounds with carbon-fluorine bonds. Compounds that contain many C-F bonds often has distinctive properties, e.g., enhanced stability, volatility, and hydrophobicity. Fluorocarbons and their derivatives are commerci ...

with the formula CF₃CHF₂. Pentafluoroethane is currently used as a

refrigerant A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulate ...

(known as R-125) and also used as a fire suppression agent in fire suppression systems. Pentafluoroethane does not deplete ozone so it has replaced earlier fluorinated chemicals that did. However while it has zero

ozone depletion potential The ozone depletion potential (ODP) of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane (R-11 or CFC-11) being fixed at an ODP of 1.0. Chlorodifluoromethane (R-22), for examp ...

, it has high

global warming potential Global warming potential (GWP) is the heat absorbed by any greenhouse gas in the atmosphere, as a multiple of the heat that would be absorbed by the same mass of carbon dioxide (). GWP is 1 for . For other gases it depends on the gas and the time ...

, reported by the

United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it ...

(EPA) as 3450 times that of carbon dioxide.

Refrigerant

Container 【 2079 】 CCRU 538017(0) 【 Pictures taken in Japan 】

Pentafluoroethane in a near azeotropic mixture with difluoromethane is known as R-410A, a common replacement for various

chlorofluorocarbon Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivatives of methane, ethane, and pro ...

s (commonly known as ''Freon'') in new refrigerant systems.

Fire suppression systems

HFC-125 (ECARO-25 / FE-25 / NAF S 125) is a gaseous fire suppression agent which can be used in clean agent fire suppression systems. In addition, HFC-125 leaves no residue on valuable equipment and material after discharge. It is generally used in situations where water from a fire sprinkler would damage expensive equipment, or where water-based fire protection is impractical, such as museums, banks, clean rooms and hospitals. The HFC-125 clean agent is stored in a pressurized container and introduced into the hazard as a gas. The agent is odorless, colorless, electrically non-conductive, non-corrosive, and leaves no residue. It is used in occupied enclosed areas that contain high-value assets. HFC-125 suppresses fire by absorbing heat energy at its molecular level faster than the heat can be generated, so the fire cannot sustain itself. It also forms free radicals to chemically interfere with the chain reaction of the combustion process. This makes it a highly effective fire fighting agent that is safe for people and causes no damage to equipment. HFC-125 is considered a Clean Agent and is therefore included in the

National Fire Protection Association The National Fire Protection Association (NFPA) is an international nonprofit organization devoted to eliminating death, injury, property and economic loss due to fire, electrical and related hazards. As of 2018, the NFPA claims to have 50,000 mem ...

's 2001 - Standard for Clean Agent Fire Extinguishing Systems.

Environmental impact

HFC-125 is a non-ozone depleting replacement for

chlorine Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is ...

- or

bromine Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table (halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a simil ...

-containing chemicals such as Halon 1301. Due to its global warming potential (GWP) of 3500 times that of CO₂ and atmospheric lifetime of 29 years, it is included in the list of controlled substances of the

Montreal Protocol The Montreal Protocol is an international treaty A treaty is a formal, legally binding written agreement between actors in international law. It is usually made by and between sovereign states, but can include international organization ...

.Montreal Protocol Section 1.1. including 2016 Kigali amendment (in effect in 2019) When introduced to the market HFC-125 was not considered safe for use in occupied spaces. The US EP
Significant New Alternative Policy
(SNAP) listing reflected this. Following the introduction and acceptance of the PBPK model in the NFPA standard 2001 on Clean Agent Fire Extinguishing Systems 2004 Edition, the restriction was relaxed and now HFC-125 can be used in occupied hazards. Generally, class B (flammable liquid) hazards require concentrations that exceed the agent's

no-observed-adverse-effect level The no-observed-adverse-effect level (NOAEL) denotes the level of exposure of an organism, found by experiment or observation, at which there is no biologically or statistically significant increase in the frequency or severity of any adverse effe ...

(NOAEL) so extra precautions must be taken to avoid prolonged exposure to the agent. At high temperatures, pentafluoroethane will decompose and produce hydrogen fluoride. This is observable as presence of sharp, pungent odour, which can be perceived in concentrations far below a dangerous level. Other decomposition products include

carbonyl fluoride Carbonyl fluoride is a chemical compound with the formula COF2. It is a carbon oxohalide. This gas, like its analog phosgene, is colourless and highly toxic. The molecule is planar with ''C''2v symmetry, bond lengths of 1.174 Å (C=O) and 1.31 ...

carbon monoxide Carbon monoxide ( chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

and

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...

. Prior to re-entry of a room where HFC-125 system has been activated to suppress a fire, the atmosphere should be tested. A
Acid Scavenging Additive
added to pentafluoroethane is able to reduce the amount of hydrogen fluoride.

Brands

ECARO-25 is a registered

trademark A trademark (also written trade mark or trade-mark) is a type of intellectual property consisting of a recognizable sign, design, or expression that identifies products or services from a particular source and distinguishes them from oth ...

of Fike Corporation. FE-25 is a registered trademark of E. I. du Pont de Nemours and Company or its affiliates. NAF S 125 (HFC-125 plus Acid Scavenging Additive) is a trademark of Safety Hi-Tech.

References

EPA site on hazards

Commercial Site on NAF S 125

Commercial Site on ECARO-25

External links

{{DEFAULTSORT:Pentafluoroethane Fluoroalkanes Fire suppression agents