A combustible material is a material that can burn (i.e. sustain a flame) in air under certain conditions. A material is flammable or inflammable if it ignites easily at room temperature. In other words, a combustible material takes more effort to ignite and a flammable material ignites almost immediately when exposed to a flame.
The degree of flammability in air depends largely on how easy the material vaporizes. This is related to its composition-specific vapor pressure, which is temperature dependent. The quantity of vapor produced can be enhanced by increasing the surface area of the material, forming a mist or dust. Wood is an example. Finely divided wood dust can undergo explosive flames and produce a blast wave. A piece of paper (made from pulp) catches on fire quite easily. A heavy oak desk is much harder to ignite, even though the wood fibers are the same in all three materials.
Common sense, and scientific consensus until the mid-1700s, suggests that material disappears when burned, as only the ash is left. Further scientific research has found that conservation of mass holds for chemical reactions. The burning of a solid material may appear to lose mass if the mass of combustion gases (such as carbon dioxide and water vapor) is not taken into account. The original mass of flammable material and the mass of the oxygen consumed (from the surrounding air) equals the mass of the flame products (ash, water, carbon dioxide, and other gases). Some metals gain mass when they burn to support the idea (because those chemical reactions capture oxygen atoms into solid compounds rather than gaseous water).
Definitions Historically, flammable, inflammable and combustible meant capable of burning.inflammable, a. (n.) 1. combustible a. and n. 1. Oxford English Dictionary. 2nd ed. 2009. CD-rom. The word "inflammable" came through French from the Latin inflammāre = "to set fire to", where the Latin preposition "in-""flammable", The American Heritage Dictionary of the English Language, 5th ed. Houghton Mifflin Harcourt Publishing Company. 2014. accessed 3/11/2015 means "in" as in "indoctrinate", rather than "not" as in "invisible" and "ineligible".
The word inflammable may be erroneously thought to mean non-flammable.Sherk, Bill. "fireproof", 500 Years of New Words. Toronto: Dundurn, 2004. 96. Print. The erroneous usage of the word inflammable is a significant safety hazard. Therefore, since the 1950s, efforts to use flammable in place of inflammable were accepted by linguists, and it is now the accepted standard in American English and British English.Garner, Bryan A., Garner's Modern American Usage. 3rd ed. New York: Oxford UP, 2009. 357. Print. Antonyms of flammable or inflammable include: non-flammable, non-inflammable, incombustible, non-combustible, not flammable, and fireproof.
Flammable applies to combustible materials that ignite easily and thus are more dangerous and more highly regulated. Less easily ignited and less-vigorously burning materials are combustible. For example, in the United States flammable liquids, by definition, have a flash point below . Combustible liquids have a flash point above . Flammable solids are solids that are readily combustible, may cause, or contribute to fire through friction. Readily combustible solids are powdered, granular, or pasty substances that easily ignite by brief contact with an ignition source, such as a burning match, and spread flame rapidly. The technical definitions vary between countries so the United Nations created the Globally Harmonized System of Classification and Labeling of Chemicals, which defines the flash point temperature of flammable liquids as between 0 and and combustible liquids between and .
Flammability Flammability is the ease with which a combustible substance can be ignited causing fire, combustion, or an explosion. The degree of difficulty required to cause the combustion of a substance is quantified through fire testing. A variety of test protocols exist to quantify flammability. The ratings achieved are used in building codes, insurance requirements, fire codes, and other regulations that govern the use of building materials as well as the storage and handling of highly flammable substances. This includes inside and outside of structures and in surface and air transportation. For instance, changing an occupancy by altering the flammability of the contents requires the owner of a building to apply for a building permit to make sure that the overall fire protection design of the facility takes the change into account.
Classification of flammability Globally Harmonized System of Classification and Labelling of Chemicals uses a four category system to classify flammable liquids using flash point and boiling point temperature.29 CFR 1910.106(a)(19) This system is used internationally to evaluate and sort substances in industrial applications, workplaces and products distributed to consumers. + GHS Classification of flammable liquids Category Category 1 Category 2 Category 3 Category 4 Flash point < < ≥ - ≤ > - ≤ Boiling point ≤ > Example liquids Gasoline (Petrol), Diethyl ether Ethanol, Isopropyl alcohol Kerosene, 1-Butanol Diesel fuel, Formic acid GHS signal word and hazard statement Danger - Extremely flammable liquid and vapor Danger - Highly flammable liquid and vapor Warning - Flammable liquid and vapor Warning - Combustible liquid
Prior to 2012, OSHA's classification of flammable and combustible liquids in regulation CFR 1910.106, was nearly identical to the National Fire Protection Association (NFPA) Flammable and Combustible Liquids Code, NFPA 30.National Archives And Records Administration. Code of Federal Regulations: Occupational Safety And Health Standards, 29 C.F.R. §1910.106 - Flammable and combustible liquids (1994) While no longer used for occupational regulations, NFPA 30's definitions are still commonly used in fire codes and NFPA codes and standards. + NFPA 30 - Flammable and Combustible Liquids Code Class I-A I-B I-C II III-A III-B Flash point < < ≥ - < ≥ - ≤ ≥ - < ≥ Boiling point < ≥ Example liquids Gasoline (Petrol), Diethyl ether Ethanol, Isopropyl alcohol Butyl alcohol, Turpentine Diesel fuel, Mineral spirits Fuel oil, Formic acid Olive oil, oil based paints
Other systems for classifications of flammable liquids exist for more specialized applications, such as NFPA 704, which uses five categories. This is intended for emergency workers to understand the hazard posed by a substance during an emergency, such as a spill. In addition to GHS, flammability classifications are incorporated into various systems designed for communicating physical and health hazards in workplaces; such as the American Coatings Association's Hazardous Materials Identification System (HMIS)
Examples of flammable substances Flammable substances include, but are not limited to: Gasoline - Petrol / a complicated mixture of hydrocarbons that includes isomers of octane, C8H18 Ethanol / CH3CH2OH Rubber Isopropyl alcohol / CH3CH(OH)CH3 Methanol / CH3OH Wood Acetone / CH3COCH3 Paper Nitromethane / CH3NO2
Examples of nonflammable substances Water Carbon tetrachloride Iron Ceramic
Furniture flammability Flammability of furniture is of concern as cigarettes and candle accidents can trigger domestic fires. In 1975, California began implementing Technical Bulletin 117 (TB 117), which required that materials such as polyurethane foam used to fill furniture be able to withstand a small open flame, equivalent to a candle, for at least 12 seconds. In polyurethane foam, furniture manufacturers typically meet TB 117 with additive halogenated organic flame retardants. No other U.S. states had similar standards. California had such a large market, manufacturers meet TB 117 in products that they distribute across the United States. The proliferation of flame retardants, especially halogenated organic flame retardants, in furniture across the United States is strongly linked to TB 117. When it became apparent that the risk-benefit ratio of this approach was unfavorable and the industry had used falsified documentation (i.e. see David Heimbach) for the use of flame retardants, California modified TB 117 to require that fabric covering upholstered furniture meet a smolder test that replaced the open flame test. Governor Jerry Brown signed the modified TB117-2013, which became effective in 2014.
Fabric flammability Lightweight textiles with porous surfaces are the most flammable fabrics. Wool is less flammable than cotton, linen, silk, or viscose (rayon). Polyester and nylon resist ignition and melt rather than catch fire. Acrylic is the most flammable synthetic fiber.
Testing A fire test can be conducted to determine the degree of flammability. Test standards used to make this determination but are not limited to the following:
Underwriters Laboratories UL 94 Flammability Testing International Electrotechnical Commission IEC 60707, 60695-11-10 and 60695-11-20 International Organization for Standardization ISO 9772 and 9773. National Fire Protection Association NFPA 287 Standard Test Methods for Measurement of Flammability of Materials in Cleanrooms Using a Fire Propagation Apparatus (FPA) NFPA 701: Standard Methods of Fire Tests for Flame Propagation of Textiles and Films NFPA 850: Recommended Practice for Fire Protection for Electric Generating Plants and High Voltage Direct Current Converter Stations
Combustibility Combustibility is a measure of how easily a substance bursts into flame, through fire or combustion. This is an important property to consider when a substance is used for construction or is being stored. It is also important in processes that produce combustible substances as a by-product. Special precautions are usually required for substances that are easily combustible. These measures may include installation of fire sprinklers or storage remote from possible sources of ignition.
Substances with low combustibility may be selected for construction where the fire risk must be reduced, such as apartment buildings, houses, or offices. If combustible resources are used there is greater chance of fire accidents and deaths. Fire resistant substances are preferred for building materials and furnishings.
Non-combustible material A non-combustible material is a substance that does not ignite, burn, support combustion, or release flammable vapors when subject to fire or heat. Any solid substance complying with either of two sets of passing criteria, listed in Section 8 of ASTM E 136 when the substance is tested in accordance with the procedure specified in ASTM E 136, is considered to be non-combustible.
Combustible dust