Flashpoint definition

Standard for gauging flammability. The most common systems for designating flammability are the Department of Transportation (DOT) definitions, the National Fire Protection Association s (NFPA) system, and the Environmental Protection Agency s (EPA) Resource Conservation and Recovery Act s (RCRA) definition of ignitable wastes, all of which use flashpoint in their schemes. The NFPA diamond, which comprises the backbone of the NFPA Hazard Signal System, uses a four-quadrant diamond to display the... 

The flash point represents the minimum temperature at which an ignitable mixture exists above a liquid surface. By definition, flashpoints are inapplicable to gases. Some solids, e.g. naphthalene and camphor, are easily volatilized on heating so that flammable mixtures develop above the solid surface and hence flash points can be determined. (However, although these substances can be ignited, they generally need to be heated above their flash points in order for combustion to be sustained ttiis is the fire point .)... 

This last inflammability parameter presents problems. After stating its definition it will be seen that measuring autoignition temperature proves to be a difficult exercise because its measurement is sensitive to the experimental conditions, even more sensitive than for flashpoints. Worse, this parameter seems to be controlled by kinetic factors far more complex to master than the thermodynamic factors that probably control flashpoints (in fact it is a liquid/vapour equilibrium). So whilst the influence of the nature of the cup metal on a flashpoint has never been demonstrated, this demonstration was easily made with autoignition temperatures. 

Flammable hquids are divided into various classes, as given in Table 3.4. The definitions depend upon the flashpoints and in some cases the boiling points of the liquids. The flashpoint of a liquid is l aUy defined in terms of specific test procedures used to determine it, but conceptually it is the minimum temperature at which a hquid forms a vapor above its surface in sufficient concentration that it may be ignited. In Table 3.4, the first temperature is in degrees Celsius and the temperature in parentheses () is the equivalent Fahrenheit temperature. 

Hazardous wastes are either listed wastes (40 CFR 261.30-.33) or characteristic wastes (40 CFR 261.21-.24). The U.S. EPA defines four characteristics for hazardous waste ignitability (40 CFR 260.21) corrosivity (40 CFR 260.22) reactivity (40 CFR 260.23) and toxicity (40 CFR 260.24). Any waste that exhibits one or more of these characteristics is classified as hazardous under RCRA. The ignitability definition includes a liquid that has a flash point less than 60 C (140 F) the EPA included ignitability to identify wastes that could cause fires during transport, storage, or disposal (e.g., used solvents). All of the solvents in Table 14.10.5 have flashpoints less than 60 C, so all could be a RCRA ignitability waste. 

A wide variety of each test exists. In addition, other tests not directly related to the quality of the adhesive may be considered. These inclnde, to an increasing extent, tests concerned with health, safety and environmental properties, for example, flashpoint and toxicity. Mention mnst also be made of BS EN 923 (Adhesives - Terms and definition), which provides a nsefnl reference to many of the terms used in the industry. 

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