Bromotrifluoromethane
Encyclopedia
Bromotrifluoromethane is an organic halide with the chemical formula C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

Br
Bromine
Bromine ") is a chemical element with the symbol Br, an atomic number of 35, and an atomic mass of 79.904. It is in the halogen element group. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826...

F
Fluorine
Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...

3. Alternative names are Halon 1301, R13B1, Halon 13B1 and BTM.

Table of physical properties

Property Value
Critical temperature (Tc) 66.9 °C (340.08 K)
Critical pressure (pc) 3.956 MPa (39.56 bar)
Critical density (ρc) 5.13 mol.l−1
Ozone depletion potential
Ozone depletion potential
The ozone depletion potential of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane being fixed at an ODP of 1.0. Chlorodifluoromethane , for example, has an ODP of 0.055...

 (ODP)
10 (CCl3F
Trichlorofluoromethane
Trichlorofluoromethane, also called freon-11, CFC-11, or R-11, is a chlorofluorocarbon. It is a colorless, nearly odorless liquid that boils at about room temperature.- Uses :It was the first widely used refrigerant...

 = 1)
Global warming potential
Global warming potential
Global-warming potential is a relative measure of how much heat a greenhouse gas traps in the atmosphere. It compares the amount of heat trapped by a certain mass of the gas in question to the amount of heat trapped by a similar mass of carbon dioxide. A GWP is calculated over a specific time...

 (GWP)
6900 (CO2
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 = 1)

Uses

It was introduced as an effective gaseous fire suppression
Gaseous fire suppression
Gaseous fire suppression is a term to describe the use of inert gases and chemical agents to extinguish a fire. Also called Clean Agent Fire Suppression. These Agents are governed by the NFPA Standard for Clean Agent Fire Extinguishing Systems - NFPA 2001 in the USA, with different standards and...

 agent in the 1960s, and was used around valuable materials, such as aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

, mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

 computers, and telecommunication switching centers
Telephone exchange
In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...

, usually in total flooding systems. It was also widely used in the maritime industry to add a third level of protection should the main and emergency fire pumps become inoperable or ineffective.

It is considered good practice to avoid all unnecessary exposure to Halon 1301, and to limit exposures to concentrations of 7 percent and below to 15 minutes. Exposure to Halon 1301 in the 5 to 7 percent range produces little, if any, noticeable effect. At levels between 7 and 10 percent, mild central nervous system effects such as dizziness and tingling in the extremities have been reported. In practice, the operators of many Halon 1301 total flooding systems evacuate the space on impending agent discharge.
There is also a risk of the production of toxic and irritant pyrolysis
Pyrolysis
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen. It involves the simultaneous change of chemical composition and physical phase, and is irreversible...

 products, mainly hydrogen bromide
Hydrogen bromide
Hydrogen bromide is the diatomic molecule HBr. HBr is a gas at standard conditions. Hydrobromic acid forms upon dissolving HBr in water. Conversely, HBr can be liberated from hydrobromic acid solutions with the addition of a dehydration agent, but not by distillation. Hydrogen bromide and...

 and hydrogen fluoride
Hydrogen fluoride
Hydrogen fluoride is a chemical compound with the formula HF. This colorless gas is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers . HF is widely used in the...

.

Due to lessons learned in the Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...

, the use of Halon 1301 began in the F-16 fighter aircraft to prevent vapors in the fuel tank
Fuel tank
A fuel tank is safe container for flammable fluids. Though any storage tank for fuel may be so called, the term is typically applied to part of an engine system in which the fuel is stored and propelled or released into an engine...

s from becoming explosive. Upon entering areas with possible unfriendly fire, Halon 1301 is injected into the fuel tanks for one-time use. Due to environmental concerns, trifluoroiodomethane (CF3I) is being considered as an alternative.

Bromotrifluoromethane was also used as a filling of the bubble chamber
Bubble chamber
A bubble chamber is a vessel filled with a superheated transparent liquid used to detect electrically charged particles moving through it. It was invented in 1952 by Donald A. Glaser, for which he was awarded the 1960 Nobel Prize in Physics...

 in the neutrino detector
Neutrino detector
A neutrino detector is a physics apparatus designed to study neutrinos. Because neutrinos are only weakly interacting with other particles of matter, neutrino detectors must be very large in order to detect a significant number of neutrinos. Neutrino detectors are often built underground to isolate...

 Gargamelle
Gargamelle
Gargamelle was a giant bubble chamber detector at CERN, designed mainly for the detection of neutrino interactions. Built in France, with a diameter of nearly 2 meters and 4.8 meters in length, Gargamelle held nearly 12 cubic meters of freon...

.

Before the dangers of Halon 1301 as an ozone depleter were known, many industrial chillers used it as an efficient refrigerant gas.

Alternatives

Alternatives to Halon 1301 in fire extinguishing systems are being deployed. Many installations from which halon is removed can be protected with fire sprinkler
Fire sprinkler
A fire sprinkler system is an active fire protection measure, consisting of a water supply system, providing adequate pressure and flowrate to a water distribution piping system, onto which fire sprinklers are connected...

s, depending on the level of damage the equipment in the space will incur by exposure to water. In other cases, different total flooding agents can be used. The alternatives for normally occupied areas include (PFC-410 or CEA-410), C3F8 (PFC-218 or CEA-308), HCFC Blend A (NAF S-III), HFC-23 (FE 13), HFC-227ea (FM 200), IG-01 (argon
Argon
Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...

), IG-55 (argonite
Argonite
Argonite is a name brand and registered trademark owned by Ginge-Kerr for a mixture of 50% argon and 50% nitrogen . It is an inert gas used in gaseous fire suppression systems. Ginge-Kerr is part of United Technologies Fire & Security...

), HFC-125, or HFC-134a. For normally unoccupied areas, the alternatives include carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

, powdered Aerosol C, CF3I, HCFC-22, HCFC-124, HFC-125, HFC-134a, gelled halocarbon/dry chemical suspension (PGA), blend of inert gas, high expansion foam systems and powdered aerosol (FS 0140), and IG-541 (Inergen
Inergen
INERGEN is a blend of inert atmospheric gases that contains 52% nitrogen, 40% argon, 8% carbon dioxide, used for fire suppression system agent. It is considered a clean agent for use in gaseous fire suppression applications. Inergen does not contain halocarbons, and has no ozone depletion...

).
Perfluorocarbons, i.e., PFCs such as C3F8, have very long atmospheric lifetimes and very high global warming potentials. Hydrochlorofluorocarbons, i.e., HCFCs including HCFC containing NAF S-III, contain chlorine and are stratospheric ozone layer depleters, although less so than Halon 1301. Their selection for usage as Halon replacements should consider those factors, and is restricted in some countries.

External links

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