Common flammables

The characteristics of flammable and combustible materials can be displayed on a ternary (triangular) graph. The characteristics of several common flammable and combustible materials are presented in Table 2. 

Upper Flammability (Explosive) Limits. (UEL ar UFL The highest percentage concentration at which a flash or flame can develop and propagate flame away from the source of ignition when in contact wath a source of ignition in a combustible material. See Tables 7-20 and 7-21 [34] for common flammable compounds. 

The flame speed of gas in air is 0.338 m/s. This is lower than most common flammable gases and is an indication of the low propensity for light-back of natural gas. 

Storage of liquid hydrogen is achieved in large well-insulated tanks from which it is dispensed to liquid tankers for transport over the road. The use of hydrogen sensors (mostly flammable sensors) in and around such facilities is a common safety practice today. As hydrogen-specific sensors and solid-state sensors become more reliable, and if their cost is reduced they will replace the more common flammable gas sensors. 

A flammable chemical substance is a solid, liquid, vapor, or gas that ignites easily and burns rapidly in air. Many of the flammable chemicals used in laboratories are flammable liquids and organic solvents. The vapors of these chemical substances form ignitable mixtures with air. Based on the flash points of these chemicals, classifications are made. The flash point of a chemical substance is defined as the lowest temperature at which a fuel-air mixture present above the surface of a liquid will ignite, if an ignition source is present. The common flammable chemical substances include, but are not restricted to, acetone, benzene, cyclohexane, ethanol, ethyl acetate, ethyl ether, gasoline, hexane, isopropyl alcohol, methanol, propanol, tetrahydro-furan and toluene, and xylene. 

TABLE IX.1 Flash Point and Autoignition Temperatures of Common Flammable Liquids and Gases... 

F]), cyclohexane (245 C [473°F]), re-pentane (260°C [500°F]), ethanol (365°C [689°F]), methanol (385 C [725 F]), and isopropanol (399°C [750 F]). Table IX.l provides flash point and autoignition temperature data for some common flammable compounds. The flammability data for these compounds, as well as those of other flammable and combustible substances, are presented throughout this book. 

It is clear from the above discussion that the combustion mechanisms even for the most simple and common flammable materials, such as solid carbon and gaseous carbon monoxide, have not yet been completely clarified not to mention the vast number of more complicated substances. 

Probably the two most hazardous classes of chemicals that you will encounter in your early days in undergraduate laboratories are corrosives and flammable liquids. Common inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid and the most common bases are sodium hydroxide, potassium hydroxide, and ammonium hydroxide. Organic solvents are the most common flammable liquids and examples of these are acetone, methanol, hexane, toluene, ethyl acetate, and dioxane. 

Propane and butane are two common flammable liquefied compressed gases. Propane has a flammable range of 2.4 to 9.5% in air, and butane 1.9 to 8.5% in air. Propane and butane have boiling points of 44°F and 31°F, respectively. Both materials are above their boiling points under ambient temperamre conditions in many parts of the country year-round. This makes the materials highly dangerous when a leak or fire occurs, especially if there is a fire with flame impingement on the container. The vapor density of propane is 1.56, and butane is 2.07. Thus, both propane and butane vapors are heavier than air. 

TABLE 4.54 Combustion Properties of Common Flammable Gases... 

TABLE 16.13 Major Ions Present in Mass Spectra of Common Flammable and Combustible Liquids... 

Groups further define the materials for which a motor is designed to be explosion proof. Group D is for common flammable solvents and fuels, such as acetone, ammonia, benzene, butane, gasoline, hexane, methane, methanol, propylene, propane, styrene, and similar compounds. Many explosion-proof motors are rated Division 1, Class I, Group D. Group C motors provide additional protection for... 

Organic Chemistiy Visualizing common flammable hydrocarbons. Naming halohydrocarbons and their uses. 

Figure 5.5 shows the minimum oxygen content for combustion for some common flammable materials. The limits of flammability are dictated by the ability of a system to propagate a flame front. Propagation does not occur until the flame front reaches about... 

Thus, to characterize an explosion, it is not enough to quote the maximum rate of pressure rise the volume, vessel geometry, turbulence, and ignition energy must also be stated. Table 5.4 lists the Kq values for some common flammable gases measured under laboratory conditions. 

Table 9.3 illustrates flammable class characteristics. Table 9.4 provides examples of common flammables and their flashpoint and class. 

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