Combustibility and flammability
A combustible material is a material that can burn (i.e., sustain a flame) in air under certain conditions. A material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable material catches fire immediately on exposure to flame.
The degree of flammability in air depends largely upon the volatility of the material - this is related to its composition-specific
Common sense (and indeed scientific consensus until the mid-1700s) would seem to suggest that material "disappears" when burned, as only the ash is left. In fact, there is an increase in weight because the flammable material reacts (or combines) chemically with oxygen, which also has mass. The original mass of flammable material and the mass of the oxygen required for flames equals the mass of the flame products (ash, water, carbon dioxide, and other gases). Antoine Lavoisier, one of the pioneers in these early insights, stated that Nothing is lost, nothing is created, everything is transformed, which would later be known as the law of conservation of mass. Lavoisier used the experimental fact that some metals gained mass when they burned to support his ideas.
Definitions
Historically, flammable, inflammable and combustible meant capable of burning.[1] The word "inflammable" came through French from the Latin inflammāre = "to set fire to", where the Latin preposition "in-"[2] means "in" as in "indoctrinate", rather than "not" as in "invisible" and "ineligible".
The word "inflammable" may be erroneously thought to mean "non-flammable". 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 less-vigorously burning materials are combustible. For example, in the United States
Flammability
Flammability is the ease with which a combustible substance can be ignited, causing
Classification of flammability
The US Government uses the Hazardous Materials Identification System (HMIS) standard for flammability ratings, as do many US regulatory agencies, and also the US National Fire Protection Association (NFPA).
The ratings are as follows:
Rating | Degree of flammability | Examples |
---|---|---|
0 | Materials that do not burn | water |
1 | Materials that must be preheated before they ignite | lubricating oils, cooking oils
|
2 | Materials that must be moderately heated or exposed to relatively high ambient temperatures before they ignite | diesel fuel |
3 | Liquids and solids that can ignite under almost all temperature conditions | gasoline, acetone |
4 | Materials that rapidly vaporize at atmospheric pressure and normal temperatures, or readily disperse in air and burn readily | natural gas, propane, butane |
Examples of flammable substances
Flammable substances include, but are not limited to:
- 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 liquids
Furniture flammability
Flammability of furniture is of concern as cigarettes and candle accidents can trigger domestic fires. In 1975, California began implementing
Fabric flammability
Lightweight textiles with porous surfaces are the most flammable fabrics.[10] Wool is less flammable than cotton, linen, silk, or viscose (rayon).[10][11] Polyester and nylon resist ignition, and melt rather than catch fire.[10][11] Acrylic is the most flammable synthetic fiber.[10]
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[12] is a substance that does not ignite, burn, support combustion, or release flammable vapors when subject to fire or heat, in the form in which it is used and under conditions anticipated. 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.[13]
Combustible dust
A number of industrial processes produce
When suspended in air (or any oxidizing environment), the fine particles of combustible dust present a potential for explosions.
Investigation of 200 dust explosions and fires, between 1980 and 2005, indicated approximately 100 fatalities and 600 injuries.
Important characteristics
Flash point
A material's
Flame point
The flame point of a material is a temperature value at which sustained flame can be supported on the material once ignited by an external source.[23] Once the flame point of a material is reached, it produces enough fuel vapors or oils to support continuous burning.
Flammability or explosive range
The
Vapor pressure
The vapor pressure of a liquid, which varies with its temperature, is a measure of how much the vapor of the liquid tends to concentrate in the surrounding atmosphere as the liquid evaporates.[25] Vapor pressure is a major determinant of the flash point and flame point, with higher vapor pressures leading to lower flash points and higher flammability ratings.
Codes
The
For existing buildings, fire codes focus on maintaining the occupancies as originally intended. In other words, if a portion of a building were designed as an apartment, one could not suddenly load it with flammable liquids and turn it into a gas storage facility, because the fire load and smoke development in that one apartment would be so immense as to overtax the active fire protection as well as the passive fire protection means for the building. The handling and use of flammable substances inside a building is subject to the local fire code, which is ordinarily enforced by the local fire prevention officer.
Code definitions
For an
- Combustible: A material that fails to meet acceptance criteria of CAN/ULC-S114, Standard Method of Test for Determination of Non-combustibility in Building Materials.
- Non-combustible: means that a material meets the acceptance criteria of CAN4-S114, "Standard Method of Test for Determination of Non-Combustibility in Building Materials".
BS 476-4:1970 defines a test for combustibility in which a technician heats three specimens of a material in a furnace. Combustibile materials are those for which any of the three specimens either:
- Makes the temperature reading from either of two thermocouples rise by 50 degrees Celsius or more above the initial furnace temperature
- Flame continuously for 10 seconds or more inside the furnace
Otherwise, the material is classified as non-combustible.
Fire testing
Various countries have tests for determining non-combustibility of materials. Most involve the heating of a specified quantity of the test specimen for a set duration. Usually, the material must not support combustion and must not lose more than a certain amount of mass. As a general rule of thumb, concrete, steel, and ceramics - in other words inorganic substances - pass these tests, so building codes list them as suitable and sometimes even mandate their use in certain applications. In Canada, for instance, firewalls must be made of concrete.
Categorization of building materials
-
DIN4102 A1 noncombustible rockwool
-
DIN 4102 B1 (difficult to ignite/often self-extinguishing) Silicone caulking used as a component in firestopping piping penetration
-
DIN 4102 B2: Timber, normal combustibility
-
DIN 4102 B3: Polyurethane foam (easy to ignite = many hydrocarbon bonds usually)
Materials can be tested for the degree of flammability and combustibility in accordance with the German DIN 4102. DIN 4102, as well as its British cousin BS 476 include for testing of passive fire protection systems, as well as some of its constituent materials.
The following are the categories in order of degree of combustibility and flammability:
Rating | Degree of flammability | Examples |
---|---|---|
A1 | 100% noncombustible (nicht brennbar) | |
A2 | ≈98% noncombustible (nicht brennbar) | |
B1 | Difficult to ignite (schwer entflammbar) | intumescents and some high end silicones |
B2 | Normal combustibility | wood |
B3 | Easily ignited (leicht entflammbar) | polystyrene |
A more recent industrial standard is the European EN 13501-1 - Fire classification of construction products and building elements—which roughly replaces A2 with A2/B, B1 with C, B2 with D/E and B3 with F.
B3 or F rated materials may not be used in building unless combined with another material that reduces the flammability of those materials.
See also
- Explosive material
- Fire
- Fire test
- Fire protection
- Active fire protection
- Passive fire protection
- Flammable liquids
- Flammable limit
- Power tool
- Surface area to volume ratio
- Ultrafine particle
- Underwriters Laboratories
Notes
References
- ^ inflammable, a. (n.) 1. combustible a. and n. 1. Oxford English Dictionary. 2nd ed. 2009. CD-rom.
- ^ "flammable", The American Heritage Dictionary of the English Language, 5th ed. Houghton Mifflin Harcourt Publishing Company. 2014. accessed 3/11/2015
- ^ Sherk, Bill. "fireproof", 500 Years of New Words. Toronto: Dundurn, 2004. 96. Print.
- ^ Garner, Bryan A., Garner's Modern American Usage. 3rd ed. New York: Oxford UP, 2009. 357. Print.
- ^ "inflammable". Common Errors in English Usage, The Web Site of Professor Paul Brians. Washington State University. Retrieved 30 June 2012.
- ^ a b "A Guide toThe Globally Harmonized System of Classification and Labeling of Chemicals (GHS)". Occupational Safety & Health Administration. U.S. Department of Labor. 2006. Archived from the original on 2007-07-02. Retrieved 2015-03-12.
- ^ California Department of Consumer Affairs, Bureau of Home Furnishings (March 2000). "Technical Bulletin 117: Requirements, test procedure and apparatus for testing the flame retardance of resilient filling" (PDF) (Report). pp. 1–8. Archived from the original (PDF) on 2014-06-11. Retrieved 2014-11-04.
- ^ "Proposed Regulations - Notice of Proposed New Flammability Standards for Upholstered Furniture/Articles Exempt from Flammability Standards". Department of Consumer Affairs, Bureau of Electronic and Appliance Repair, Home Furnishings and Thermal Insulation. Archived from the original on 2013-05-24. Retrieved 2014-11-04.
- ^ "Calif. law change sparks debate over use of flame retardants in furniture". PBS Newshour. January 1, 2014. Archived from the original on Nov 2, 2014. Retrieved November 1, 2014.
- ^ a b c d "These clothes are the most flammable". Sikker hverdag. Retrieved 2023-06-20.
- ^ a b "Flammable Fabrics". City of Phoenix. Retrieved 2023-06-20.
- ^ "NCDOI OSFM Evaluation Services: Subject of White Paper: Classification of Building Materials According to Combustibility" (PDF). NC DOI. 8 September 2011. Archived from the original (PDF) on Dec 6, 2018. Retrieved 6 December 2018.
- ^ "Standard Test Method for Assessing Combustibility of Materials Using a Vertical Tube Furnace at 750°C". ASTM International. Oct 10, 2022. Retrieved 2023-04-10.
- ^ a b c "Hazard Communication Guidance for Combustible Dusts". Occupational Safety and Health Administration. Retrieved 2023-04-10.
- ^ OCLC 246682805, archived from the original(PDF) on 21 December 2016, retrieved 21 August 2017
- OCLC 8391202
- ^ Smith, Sandy (7 February 2012) "Only OSHA Has Not Adopted Chemical Safety Board Recommendations Stemming from Imperial Sugar Explosion" EHS Today
- ^ "NFPA 61 Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities"
- ^ Zalosh, Robert et al. (April 2005) "Dust Explosion Scenarios and Case Histories in the CCPS Guidelines for Safe Handling of Powders and Bulk Solids" 39th AIChE Loss Prevention Symposium Session on Dust Explosions Atlanta, Georgia
- ^ O'Brien, Michael (2008) "Controlling Static Hazards is Key to Preventing Combustible Cloud Explosions" Newton Gale, Inc. Archived 2012-05-07 at the Wayback Machine
- ^ The chief executive, John C. Sheptor, said the probable cause of the explosion was sugar dust building up in storage areas, which could have been ignited by static electricity or a spark. Dewan, Shaila (9 February 2008). "Lives and a Georgia Community's Anchor Are Lost". The New York Times. Retrieved 7 May 2012.
- ^ Chapman, Dan (13 April 2008). "Sugar refinery near Savannah determined to rebuild". The Atlanta Journal-Constitution. Archived from the original on June 29, 2011. Retrieved 7 May 2012.
- ^ ISBN 978-0-08-102728-8, retrieved 2023-04-10
- ^ ISBN 978-0-7506-8580-1, retrieved 2023-04-10
- ^ "Vapor Pressure". ch302.cm.utexas.edu. Retrieved 2023-04-10.
- ^ "Digital Codes". codes.iccsafe.org. Retrieved 2023-04-10.
External links
This article's use of external links may not follow Wikipedia's policies or guidelines. (December 2019) |
- Fire Performance of Ageing Cable Compounds, NFPA Treatise by Perry Marteny
- CAN4-S114 CAN/ULC-S114 Abstract
- "Combustible Dust: Agricultural Related Fires and Explosions Increasing, but Preventable" Division of Occupational Safety and Health, N.C. Department of Labor
- Combustible Dust: A Major Hot Work Hazard" Division of Occupational Safety and Health, N.C. Department of Labor