Could it burn or explode?

Key Points

  • Many solids, liquids, and gases have the potential to burn—and some have the potential to explode. Substances that can burn are either combustibleCan be ignited and burned. (they can burn) or flammableEasy to ignite and burns readily. (they burn readily). The potential for fire or explosionA chemical or physical process in which the rate at which energy is being generated exceeds its ability to escape to its surrounding environment. The hazards of an explosion can include a shock wave (especially near the point of explosion) and projectiles generated by the shock wave. is much greater for flammable materials.
  • To find out whether a transported substance could burn or explode, check container labels and/or vehicle placards. If the substance is explosiveA material synthesized or mixed deliberately to allow the very rapid release of chemical energy (that is, an explosion). Also, a chemical substance that is intrinsically unstable and liable to detonate under conditions that might reasonably be encountered. and is properly placarded or labeled, you should see a bursting ball symbol on the label or placard. If it's flammable, you should see a flame symbol.
  • To find out whether a stored material could burn or explode, check its NFPA diamond label. A number greater than 0 in the red section indicates that a fire hazardA hazard category that includes chemicals described as flammable, combustible liquid, pyrophoric, or oxidizers (as defined by 29 CFR 1910.1200). exists. Higher numbers (3 and 4) indicate a highly flammable substance.
  • Check the chemical's datasheet in CAMEO 365betÓéŔÖ to find out more about its potential to burn or explode, and to see response recommendations.

Backgrounder

A substance with the potential to burn is either combustible (it can burn under ordinary conditions) or flammable (it burns readily under ordinary conditions). The potential for fire or explosion is much greater for flammable materials. Common flammable substances range from the obvious (such as gasoline, paint thinner, LPGLiquefied petroleum gas., and LNGLiquefied natural gas.) to the less obvious (such as some grain, starch, and food dusts).

Many solids, liquids, and gases are serious fire or explosion hazards. See example categoriesSee example categories

  • Flammable liquids have flash pointsThe lowest temperature at which a liquid gives off enough vapor to be ignited at its surface. of no more than 141°F (60.5°C). Many flammable liquids have flash points well below ambient temperature (such as benzene, carbon bisulfide, toluene, and xylene). When such a low-flash point liquid is spilled at ambient or higher temperatures, enough vaporThe gas given off by a substance that is liquid (or solid) at normal temperatures and pressures. is released into the air to ignite if it contacts an ignition source (such as a spark, static electricity, or a flame).
  • Flammable gases include flammable compressed gases stored in cylinders under high pressures. A small amount of highly compressed flammable gas, if released, can fill a large space with a potentially explosive mixture of gas and air. Example flammable gases are ammonia, hydrogen sulfide, methane, and propane.
  • Flammable solids include materials (such as packaging materials, some textiles, and plastic foam) that burn fiercely when ignited. Desensitized explosives (that is, explosives treated to suppress their explosive properties) are another type of flammable solid.
  • Flammable dusts can disperse in the air; if ignited, they can explode violently.
  • Oxygen, if released into the air, creates an oxygen-enriched atmosphere in which flammable and combustible materials burn very vigorously—or even ignite spontaneously.
  • Reactive chemicals (such as organicGenerally, compounds that contain the element carbon, except for some carbon-containing compounds that are considered to be inorganic (carbon oxides, carbides, carbon disulfide, phosgene, the cyanides of the metals, and carbonyl sulfide). peroxides) can explode if they are handled incorrectly.

Determining Whether It Could Burn or Explode

First, find out whether it has the potential to burn or explode.

  • If it's a transported substance, check container labels and/or vehicle placards.

    If the substance is explosive and is properly placarded or labeled, you should see a bursting ball symbol and/or the words "Explosives" or "Blasting Agents" on the label or placard (as in the examples shown below).

    Sample placard for hazard divisions 1.1, 1.2, and 1.3.Sample placard for hazard divisions 1.1, 1.2, and 1.3.Sample placard for hazard division 1.4.Sample placard for hazard division 1.5.

    If it's flammable and is properly placarded or labeled, you should see a flame symbol (as in the examples shown below).

    Sample placard for hazard division 2.1 (flammable gases).A sample placard for gasoline.Sample placard for hazard class 3 (flammable liquids).Sample placard for hazard division 5.2 (organic peroxides).
  • If it's stored in a container at a fixed facility (such as a chemical facility, warehouse, or shed), check for an NFPA diamond placard on the container. In the diamond, a number greater than 0 in the red section indicates that a fire hazard exists. A higher number (up to 4) indicates a greater hazard. For example, the "3" in the red, flammabilityA substance's tendency to ignite or take flame. Flammability is closely related to the volatility of a substance (and is not its relative ability to burn in the presence of oxygen with the evolution of heat). section of the NFPA diamond for tetramethyllead (shown below) indicates that this substance is flammable, igniting at normal temperatures.

    The NFPA diamond for tetramethyllead has a 3 in the fire hazard section, a 3 in the reactivity hazard section, a 2 in the health hazard section, and a no water indication in the special hazards section.
  • For detailed information about a chemical's fire or explosion hazard—and for response recommendations—look up the chemical datasheet in CAMEO 365betÓéŔÖ.

Second, find out whether the conditions make a fire or explosion likely. See example conditionsSee example conditions

  • Increased temperature: Higher temperatures increase the rate of evaporation of vapor from a spilled flammable liquid, making it more likely that the concentrationThe amount of a chemical present in a given weight or volume of air. Concentration of a gas in air may be expressed in units such as parts per million (by volume) or milligrams per cubic meter. of the evaporating vapor will reach the flammable range.
  • Sources of ignition: An open flame, static electricity, hot plate, a cigarette, or sparks can ignite a flammable vapor or other flammable material.
  • Vapor confinement: Some degree of confinement―either complete (in a closed space such as a warehouse or a vessel's hold) or partial (such as between buildings or under a dock or pier)—makes it more likely that a flammable vapor's concentration will reach the flammable range.
  • Poor ventilation: Poor ventilation also increases the chances that the concentration of a flammable vapor will rise to a dangerous level.
  • Dampness: Microbial activity in materials like fish meal and stored grain (when stored wet or damp) can generate enough internal heat to ignite the material.
  • Contact between incompatible substances: Contact between substances that react together increases the chance of a hazardous reactionThe change that takes place when two or more substances interact to form new substances. that could lead to a fire or explosion. If there's a chance that two or more hazardous substances could mix, use CAMEO 365betÓéŔÖ to predict reactivity.

Related Topics