In a fire extinguisher, the powder is driven out of its container by either nitrogen or CO2 under pressure.
Related terms:
Emergency management and security
Ian Sutton, in Process Risk and Reliability Management, 2010
Portable Fire Extinguishers
Portable fire extinguishers include both self-contained fire extinguishing equipment that can be carried by one person and wheeled units that can be handled by one or two people. Due to their limited capacity, portable fire extinguishers are designed to control fires that are just starting or that are of limited size.
Location
Portable fire extinguishers need to be located near the equipment to be protected, but not so close that they can become involved in the fire or that a person cannot reach them. The suggested distance from their point of use is between 5 and 15m. From any grade level point in a process plant, the maximum horizontal distance to a dry chemical extinguisher should not exceed 15m. Extinguisher locations should be conspicuous, clearly marked, and visible from several directions. The locations should not be blocked with materials or equipment that might conceal or impede access to them.
Types
Table 11.4 provides guidance regarding the selection of portable extinguishers.
Table 11.4. Selection of Portable Fire Extinguishers
| Class A – ordinary combustible hazards |
| Water can be used. Multipurpose dry chemical may be considered for some warehouse facilities and offices where lightweight fire extinguishers are desirable for easier handling. |
| Class B – flammable liquids and gases |
The following fire extinguishing materials can be used:
|
| Class C – electrical hazards and delicate electronic equipment |
|
Water extinguishers
The superior cooling capacity of water over other extinguishing agents makes it particularly effective on fires involving ordinary combustibles such as wood, paper, fabrics, or rubber. Water extinguishers do not require extensive cleanup after use and they are non-corrosive to electronic circuitry, unlike dry chemical extinguishers. When water extinguishers are subject to freezing weather antifreeze is added.
Carbon dioxide extinguishers
Carbon dioxide (CO2) is stored in extinguishers in the liquid phase. It vaporizes when released thereby smothering a fire by excluding the air (oxygen) needed for combustion. As already noted, Carbon dioxide extinguishers are preferable to water or dry chemical extinguishers where water damage and fouling of delicate electrical, electronic, or laboratory equipment cannot be tolerated or where cleanup is a consideration.
If a CO2 extinguisher is discharged in a confined space then that space must be ventilated once the fire is extinguished.
Dry chemical extinguishers
Many types of dry chemical extinguishing agents are available. Those shown below are used in the process industries.
- ▪
Sodium bicarbonate;
- ▪
Potassium bicarbonate base (Purple K); and
- ▪
Monoammonium phosphate.
Sodium bicarbonate was the original dry chemical extinguishing agent. The chemical currently available is a mixture consisting primarily of sodium bicarbonate with various additives to improve flow and storage characteristics. Chief among the additives is a silicone polymer. It is used to prevent moisture absorption and consequent caking of chemical. It works by interrupting the propagation of the flame. Its electrical resistivity is high, and it is nontoxic. This agent may be used for extinguishing fires involving flammable liquids, gases and electrical equipment. It is not effective in extinguishing deep-seated fires in ordinary combustibles.
Potassium bicarbonate chemical, whose physical properties are similar to sodium bicarbonate, is effective at extinguishing fires involving flammable liquids and gases. It is also suitable for use on fires involving electrical equipment. It is not effective in extinguishing deep-seated fires in ordinary combustibles.
Monoammonium phosphate based chemical is effective in controlling and extinguishing fires involving flammable liquids and gases, ordinary combustible materials, and electrical equipment. It is recommended where piped water is not available, where freezing conditions are expected, or where a combination of different classes of hazards exists. It has physical properties similar to the sodium bicarbonate chemical but is more effective on flammable liquid fires. It is corrosive to electronic circuitry. It should not be mixed bicarbonate dry chemicals. A chemical reaction can occur in the extinguisher that generates CO2 and other gases; the pressure buildup could rupture the extinguisher.
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Methods of Fire Suppression
Dennis P. Nolan, in Handbook of Fire and Explosion Protection Engineering Principles for Oil, Gas, Chemical, and Related Facilities (Fourth Edition), 2019
19.1 Portable Fire Extinguishers
Historical evidence indicates that portable (i.e., manually manipulated and operated) fire extinguishers are the most common method of extinguishing a fire in the process industry in the incipient stage. Human surveillance combined with the ability to quickly and effectively react to the beginning of an incipient fire has prevented countless process incidents from developing into large-scale disasters. The objective of providing portable fire extinguishers is to have an available supply of plentiful extinguishers that can be easily used in the early stages of a fire. When these extinguishing means are exhausted or the incipient fire has grown to the point of uncontrollability by manual methods, fixed fire suppression systems and process incident control systems should be activated (e.g., emergency shutdown). Only personnel trained in portable fire extinguisher use should be expected to use them.
A portable fire extinguisher is a device used to put out fires of limited size. Portable extinguishers are classified by expected application on a specific type of fire (i.e., A, B, C, or D) and the expected area of suppression. The four types of fires are grouped according to the type of material that is burning. Class A fires are those in which ordinary combustibles such as wood, cloth, and paper are burning. Class B fires are those in which flammable liquids, oils, and grease are burning. Class C fires are those involving live electrical equipment. Class D fires involve combustible metals such as magnesium, potassium, and sodium.
The numerical rating on the fire extinguisher is a relative rating number. It is assigned by recognized testing laboratories for the amount of average fire area that can be extinguished according to methods established by the National Fire Protection Association (NFPA). The rating does not equate to the amount of square feet that can be expected to be extinguished by an individual using the extinguisher.
The classes of portable fire extinguishers manufactured and used in industry are defined below. Other countries have similar classifications (although these may not be exactly the same).
Extinguishers for Class A fires
Class A fire extinguishers are usually water-based. Water provides a heat-absorbing (cooling) effect on the burning material to extinguish the fire. Pressurized water extinguishers use air under pressure to expel the water which is directed with a short hose.
Extinguishers for Class B fires
Class B fires are put out by excluding air, by slowing down the release of flammable vapors or by interrupting the chain reaction of the combustion. Three types of extinguishing agents are typically used—carbon dioxide, dry chemical, and foam water for fires involving flammable liquids, greases, and oils. Carbon dioxide is a compressed gas agent that prevents combustion by displacing the oxygen in the air surrounding the fire. The two types of dry chemical extinguishers include one that contains ordinary sodium potassium bicarbonate, urea potassium bicarbonate, and potassium chloride base agents. The second, multipurpose type contains an ammonium phosphate base. The multipurpose extinguisher can be used on Class A, B, and C fires. Most dry chemical extinguishers use stored pressure to discharge the agent, and the fire is extinguished mainly by the interruption of the combustion chain reaction. Foam extinguishers use an aqueous film-forming foam (AFFF) agent that expels a layer of foam when it is discharged through a nozzle. It acts as a barrier to exclude oxygen from a fire.
Extinguishers for Class C fires
The extinguishing agent in a Class C fire extinguisher must be electrically nonconductive. Both carbon dioxide and dry chemicals can be used for electrical fires. An advantage of carbon dioxide is that it leaves no residue after the fire is extinguished. When electrical equipment is not energized, extinguishers for Class A or B fires may be used. Note that since an extinguisher rated solely for a Class C fire is not manufactured, and an ABC- or BC-rated fire extinguisher will have to be specified for this hazard application.
Extinguishers for Class D fires
A heat-absorbing extinguishing medium is needed for fires in combustible metals. Also, the extinguishing medium must not react with the burning metal. The extinguishing agents, known as dry powders, cover the burning metal and provide a smothering blanket.
The extinguisher label provides operating instructions and identifies the class or classes of the fire on which the extinguisher may be used safely. Approved extinguishers also carry the labels of the laboratories at which they were tested.
Portable fire extinguishers should be positioned in all process facility areas so that the travel distance to any extinguisher is 15m (50ft) or less. They are generally sited on the main walkways or exits from an area, near the high hazard itself and near other emergency devices. They are mounted so individuals can easily retrieve them, typically approximately 1m (2.5ft) from the walking surface with red highlighting at the mounting location.
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Industrial Examples
Mukesh Doble, Anil Kumar Kruthiventi, in Green Chemistry and Engineering, 2007
Fire Extinguishers and Flame Retardants
Traditionally, fire extinguishers have utilized halogens (CFCs), which today are well-known ozone-depleting agents. They also harm aquatic systems and contaminate water supplies. Pyrocool is a nontoxic, biodegradable, fire-extinguishing and cooling agent that can replace the traditional extinguishers, is just as effective in putting out fires, and does not deplete the ozone layer or persist in the environment, unlike CFCs.
Epoxy phenolic molding compounds (EMC) are mixtures of chemicals containing a base polymer resin matrix and various additives. Usually these additives are brominated epoxy resin and antimony oxide, which function as flame retardants. These compounds produce toxic fumes during flame and are also dangerous for the environment. In the last few years research has focused on developing polymers containing halogen-free flame-retardant additives, which lead to compounds containing P, Si, B, N, Al(OH)3, and Mg(OH)2. In addition to their low toxicity, their main advantages are that, in the case of fire, they do not produce dioxin and halogen acids, and they generate low amounts of smoke. Recently the microelectronics industry developed new halogen and antimony-free molding compounds based on phosphorous-based, organic, flame-retardant additives. These materials reduce the presence of toxic elements in the electronic package and the environment. It is known that halogens and other ionic impurities are responsible for metal corrosion under bias, humidity, and high temperatures. Elimination of these compounds in the formulation increases the life of these materials.
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Fires
Daniel A. Vallero PhD, Trevor M. Letcher MSc(Natal), PhD(Natal), BEd(Natal), FRSC, in Unraveling Environmental Disasters, 2013
Dry Powders
Sand is a cheap and useful extinguisher of fires. It acts as a smothering agent separating the fuel from the air. In addition to sand, sodium bicarbonate (NaHCO3) is used as a dry chemical for class A, B, and C fires. Sodium bicarbonate acts in a very different way to sand. It decomposes at 270°C according to the reaction
(7.4)
It acts in a number of ways; the decomposition products are water (a good fire-fighting chemical), CO2 (which smothers the fire), and sodium carbonate powder which also acts as an inert smothering agent. Further, the reaction is endothermic, so it absorbs heat from the fire and this helps in reducing the temperature. In a fire extinguisher, the powder is driven out of its container by either nitrogen or CO2 under pressure.
The foregoing thermodynamic factors influence not only the extent and duration of a fire disaster but also the type of damage. For example, the choice of fire extinguishing materials can affect the types of emissions released from the fire. This could entail a trade-off between fire control and emissions that could impact health and environmental quality. We shall now consider some notorious fires that have had disastrous effects on the environment.
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Volume 5
W.T. Tsai, in Encyclopedia of Environmental Health (Second Edition), 2019
Fire Extinguisher or Fire Suppression Agent
Traditionally, halons have been extensively used as effective fire extinguishers in fixed, total flooding systems for protecting sensitive electrical equipment. Owing to the Montreal Protocol, the phaseout of production of halons (i.e., halon 1301 and halon 1211) has been effective in the developed countries since 1994. The regulation stimulated tremendous efforts to search for acceptable replacements and alternatives including perfluorocarbons. Because n-C6F14 is electrically nonconductive and leaves no residue after extinguishment of fire, it has been listed as an acceptable substitute for halon 1211 (CF2ClBr) streaming agents subject to narrowed use limits (i.e., nonresidential uses) according to the SNAP Program as of October 1, 2004.
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Determination of noninsecticidal compounds in soil
T.R. Crompton, in Determination of Toxic Organic Chemicals in Natural Waters, Sediments and Soils, 2019
Perfluorooctane sulphonyl fluoride
These substances are widely applied to the production of water repellents, fire extinguishers and surface coating of paper and textiles in the 1960s because of their perfect surface activity and stability.
This group of compounds has been introduced into the environment in recent years. Because of their lipophilic characteristics they have been detected in human and animal tissue.
In May 2001 the Stockholm Convention on persistent organic compounds was brought into effect. In 2009 perfluorooctane sulphonate and its precursor perfluorooctanoic acid were listed.
Meng et al. [201] determined perfluorooctane sulphenyl fluoride and developed a method using LC with UV and fluorescence detection.
In this study a new method was developed by derivatising perfluorooctane sulphenyl fluoride with 1-naphthol to form 1-naphthylperfluorooctanesulphonate that allowed rapid qualitative and quantitative analysis using LC–UV and LC–FLD. The derivatising product was confirmed from the analyses by proton nuclear magnetic resonance (NMR) and quadrupole-time-of-flight MS. The LC–FLD method demonstrated good linearity in the 1-naphthylperfluorooctanesulphonatelate concentration range from 20µgL−1 to 20ngL−1 with correlation coefficient better than 0.00, and an instrumental detection limit of 1.5pgµL−1.
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Hepatic Toxicology
J.E. Manautou, ... L.M. Aleksunes, in Comprehensive Toxicology, 2010
9.08.3.5.2 Carbon tetrachloride
Carbon tetrachloride (CCl4) is a compound that was previously used as a dry cleaning solvent, a refrigerant, and also in fire extinguishers. Its industrial use has been largely abandoned due to well-documented adverse health effects. Exposure to CCl4 results in centrilobular hepatic necrosis. CCl4 is metabolized by CYP2E1 to the highly reactive trichloromethyl free radical, which causes hepatocellular damage through lipid peroxidation (Manibusan et al. 2007). For more on CCl4 hepatotoxicity, please see Chapter 09.20.
Natkatsukasa et al. (1993) reported increased Mdr1a, Mdr1b, and Mdr2 gene expression in rat liver after toxic CCl4 administration. In another study, CCl4 exposure caused a decrease in Ntcp and Oatp1a1 mRNA levels in rat liver (Geier et al. 2002b). Reduced Oatp1b2 and Ntcp protein expression was also noted. When hepatic efflux transporters were examined during CCl4 toxicity in rats, increased Pgp and decreased Mrp2 protein levels were detected, along with corresponding changes in their transport activity (Song et al. 2003). Analysis of multiple transporters in mice revealed that CCl4 decreased mRNA expression of the basolateral uptake transporters Oatp1a1, Oatp1b2, and Ntcp, and simultaneously increased mRNA levels for the efflux transporters Mrp1, Mrp2, and Mrp4 (Aleksunes et al. 2005). Western blot analysis demonstrated reduced Ntcp and increased Mrp1, Mrp2, and Mrp4 in these mice (Aleksunes et al. 2006). Similar to the expression pattern seen after APAP administration, upregulation of Mrp4 protein was observed in hepatocytes adjacent to the central vein after CCl4 exposure (Figure 9) (Aleksunes et al. 2006). Microarray analysis of livers from rats treated with CCl4 confirmed some of the mouse observations. Gene expression of Mdr1a, Mdr1b, Mrp1, and Mrp4 was increased by CCl4, while the expression of Mrp2, Mrp6, Oct1, and Oat3 was decreased (Okumura et al. 2007).
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Disciplines Involved in Offshore Platform Design
Naeim Nouri Samie MSc Hydraulic Structures, in Practical Engineering Management of Offshore Oil and Gas Platforms, 2016
2.9.3 Passive Protection
Passive and active protections are used in offshore platforms. Active protection is achieved by means of fire water pump, sprinklers, hydrants, hose reels, chemical extinguishers, foams, deluge valves, etc. Passive protection is achieved by providing specifically rated barriers, walls with the required fire rating, special coatings, etc. These walls shall be capable of tolerating temperature increase as per code requirement. They are classified as A-, H-, and J-rated walls. B-rated walls are only comfort insulation. Standard fire temperature and duration as per ISO 834 (EN1364–1) is shown in Table2.10. With temperature in °C and time in minutes, the following formulas represent standard and hydrocarbon fire test curves. ISO standard fire curve is somehow different from ASTM E−119 standard curve.
Table2.10. Standard fire temperature variation
| Duration (Min) | 3 | 5 | 10 | 15 | 30 | 60 | |
|---|---|---|---|---|---|---|---|
| Standard fire Temperature (°C) | A | 502 | 576 | 679 | 738 | 842 | 945 |
| H | 887 | 948 | 1034 | 1071 | 1098 | 1100 | |
Standard Fire: T=20+345log(8t+1)
Hydrocarbon Fire: T=20+1080[1−0.325exp(−0.167t)−0.675exp(−2.5t)]
A-rated walls are for general fire case. The selected compartment shall be able to provide structural resistance against normal operational loads and limit heat transfer for a specified duration. For example, A60 means durability for 60min against class A fire. H-rated walls have the same condition against hydrocarbon fires. J-rated walls shall resist jet fires. This is caused by sudden leakage and ignition of gas. In many cases this may be accompanied by blasts. Therefore for J-rated conditions a blast overpressure is also identified. Blast pressure reduces with square root of distance. Blast load for a localized impact is much more than a large area. Detailed safety studies are needed to calculate blast load and specify wall/deck ratings.
Structural steel with special coating systems is needed to achieve the required fire rating. Coating may be applied on structural wall, columns, braces, beams, joints, decks, vessels, piping manifolds, and valves. For valves that require periodic inspection, coating shall be of a removable jacket type. Both type of fixed-shape and flexible jackets are available. Required thickness shall be calculated for each case. The important feature of these coatings is that heat transfer from the face adjacent to the fire to the face adjacent to the metal surface is very much limited.
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Carbon Dioxide
S. Goel, D. Agarwal, in Encyclopedia of Toxicology (Third Edition), 2014
Uses
Carbon dioxide is used in the synthesis of urea, for organic synthesis, in the manufacture of dry ice and aspirin. It is also used in soft drinks, welding, fire extinguishers, and aerosol propellants. CO2 is often used as a pesticide to store grains (at 60% concentration), respiratory stimulant, anesthetic, and euthanizing agent. It is essential in in vitro cell culture environment at 5%, where it dissolves in the culture media to form bicarbonate (HCO3−) and acts as a buffer to help maintain the pH of CO2. Industries that use carbon dioxide include fire extinguishing; processing, preserving, and freezing of food; metal working; livestock slaughtering; oil and gas recovery; and foundries. It is also used to produce harmless smoke or fumes on a stage, chill golf ball centers before winding, and fumigate rice.
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Source Identification and Age Dating ofChlorinated Solvents
Robert D. Morrison, Brian L. Murphy, in Introduction to Environmental Forensics (Third Edition), 2015
9.3.4 Carbon Tetrachloride
Compared to other chlorinated solvent products, little historical information regarding manufacturing impurities in carbon tetrachloride is available in the peer-reviewed technical literature. An early use of carbon tetrachloride was as a fire extinguisher fluid; although not a manufacturing impurity, a 1911 patent identified the use of 1.5% by volume oil of amber and the same quantity ofnitrobenzeol (Davidson, 1911; US War Department, 1943). When exposed to heat, however, it was found that carbon tetrachloride produced phosgene gas, which led to the recall of fire extinguishers using carbon tetrachloride in the late 1960s. AUS War Department Technical Manual (TM 9-850) of August 24, 1944, allowed the mixture of TCE (10%) as a freezing point depressant with carbon tetrachloride in fire extinguishers.
Correspondence in the 1924 British Medical Journal identified carbon bisulphide (carbon disulfide) as the most common impurity in carbon tetrachloride (Dale, 1924). The presence of carbon disulfide is not surprising as nearly all of the carbon tetrachloride produced in the United States prior to 1950 was manufactured by the chlorination of carbon disulfide, typically with a catalyst such as ferric chloride (Holbrook, 1991; Doherty, 2000a).
A 1946 article lists, by percent volume, 1,2-dichloroethane (0-2%), TCE (0-1%), PCE (0-1.6%), hexachloroethane (0-0.02%), and 1,1,2,2-tetrachloroethane in commercial grade carbon tetrachloride (Williams, 1946). In 1959, an analysis by Dow Chemical Company of carbon tetrachloride for the purpose of identifying trace impurities identified 1,2-dichloromethane, 2-propanone (acetone), carbon disulfide, chloroform, TCE, and PCE (Kiley and Scheddel, 1959). In 1991, specifications for technical grade carbon tetrachloride carbon tetrachloride were to contain no more than 1 ppm of carbon disulfide, 20 ppm of bromine, and 150 ppm of chloroform if manufactured via the carbon disulfide chlorination method (Holbrook, 1991). In 1994, trichloromethane, carbon disulfide, TCE, and PCE were detected in high-purity carbon tetrachloride (Ogino and Sakai, 1994).
A 2010 analysis of high-purity grade carbon tetrachloride sponsored by the Russian Foundation for Basic Research identified 24 impurities including TCE, PCE, 1,2-DCA, chloroform, benzene, hexachloroethane, and carbon disulphide. For high-purity grade 18-4 TU (Technical Specification 6-09-3219-84) carbon tetrachloride, impurities with the highest concentrations included 1,2-DCA, TCE, and benzene (Krylov etal., 2010). Subsequent testing of a carbon tetrachloride sample and its equilibrated vapor-phase condensate confirmed the presence of PCE, hexachloroethane, and phosgene (see Table 9.5).
TABLE 9.5. Analysis of Carbon Tetrachloride Stock Sample and Condensate of Equilibrium Vapor Phase
| Impurity | Stock Sample (n = 5) | Vapor Phase Condensate (wt %) |
|---|---|---|
| Tetrachloroethylene (PCE) | (8 ± 3) × 10-7 | (1.6 ± 0.2) × 10-5 |
| Phosgene | (3.3 ± 0.5) × 10-6 | (1.1 ± 0.2) × 10-6 |
| Hexachloroethane | (4.0 ± 0.9) × 10-7 | < 4 × 10-8 |
As with other chlorinated solvents, when using manufacturing impurities for forensic purposes it is important to distinguish their presence as a manufacturing impurity versus as a stabilizer or intentional ingredient (Missbach, 1936, 1937a, 1937b, 1937c; Ohlmann, 1945; Davidowich and Leeds, 1964). Although TCE was identified in the 1959 and 2010 samples as a manufacturing impurity, TCE was also intentionally added to carbon tetrachloride as a freezing-point depressant (carbon tetrachloride freezes at -22.9oC and TCE at -89oC) used in fire extinguishers in the 1940s (US War Department, 1944).
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