Safety autoignition temperature

Boiling point Specific gravity Specific gravity temperature Solubility in water at 20°C HEALTH SAFETY Autoignition temperature DOT class... 

Tables 16 and 17 Hst tke analytical test methods for different properties of interest. The Manufacturing Chemists Association, Inc. (MCA) has pubUshed the Chemical Safety Data Sheet SD 63, which describes in detail procedures for safe handling of use of toluene (46). The Interstate Commerce Commission classifies toluene as a flammable Hquid. Accordingly, it must be packaged in authorized containers, and shipping must comply with ICC regulations. Properties related to safe handling are autoignition temperature, 536°C explosive limits, 1.27—7.0 vol % in air and flash point 4.4°C, closed cup.

The low autoignition temperature of benzaldehyde (192°C) presents safety problems since benzaldehyde can be ignited by exposure to low pressure steam piping, for example. Benzaldehyde may also spontaneously ignite when soaked into rags or clothing or adsorbed onto activated carbon (13). 

The autoignition temperature is the minimum temperature for a substance to initiate self-combustion in air in the absence of a spark or flame. The temperature is no lower than and is generahy considerably higher than the temperature corresponding to the upper flammabihty limit. Large differences can occur in reported values determined by different procedures. The lowest reasonable value should be accepted in order to assure safety. Values are also sometimes given in oxygen rather than in air. 

The combustion characteristics of liquid fuels are similarly determined by measures of their ability to sustain a flame. Two measures of the combustion characteristics of liquid fuels especially related to safety are flash point and autoignition temperature. The flash point is the maximum temperature at which a liquid fuel can be maintained in an open vessel exposed to air before which it will sustain a flame... 

Hazard, i.e. the potential of the material to cause injury under certain conditions (flammability, explosion limits in air, ignition and autoignition temperatures, static electricity (explosions have occurred during drying due to static electricity), dust explosion, boiling point, fire protection (specification of extinguishers, compounds formed when firing), R S (nature of special risk and safety precautions). Table 5.2-5 lists hazards associated with typical chemical reactions. 

Anon., ABCM Quart. Safety Summ., 1943, 14, 18 Commercial iron carbonyl (fl.p.35°C) has an autoignition temperature in contact with brass of 93°C, lower than that of carbon disulfide. 

Calculation of hot surface ignition temperature is complex and depends on many variables. From a safety perspective, it is often safest to assume that a surface with a normal temperature slightly below the autoignition temperature is a potential ignition source. 

The flash point, vapor pressure, and autoignition temperature values provide important information about the volatility of fuels and solvents. Likewise, the UN number, hazard class, and safety profile information of products provide information about the safe shipping and handling of fuels, oils, and solvents. 

PVC plastisol propellant having the chemical composition of standard Arcite (composition given above) ignites at 540° to 550°F. when its temperature is increased about 30°F./min. (16, 17). Thus, there is an ample margin of safety between the autoignition temperature and the curing temperature, which is about 200 °F. lower (19). 

Compatability of ingredients is always important. Particularly important to safe handling is the autoignition temperature and friction sensitivity of the propellant. Small changes in the formulation can often effect these important properties. An example is the sensitivity of some propellant formulations to extremely small amounts of chlorate. Safety precautions must always include consideration of the chemistry. By following this practice, the propellant industry has experienced an excellent safety record while making unusual progress in the application of viscoelastic materials in case-bonded solid propellant rockets. 

Flash point and autoignition temperature are technological properties of compounds and important safety parameters [Katritzky, Maran et al., 2000], often used as one descriptive characteristic of liquid fuel, but also used to describe liquids that are not used intentionally as fuels. 

Hash devolatilization is a simple and effective method to remove the majority of solvent and unreacted monomers from the polymer solution. Product from the reactor is charged to a flash vessel and throttled to vacuum conditions whereby the volatile solvent and monomers are recovered and condensed. In the process, the polymer melt cools, sometimes considerably, due to the evaporation of volatiles. The polymer product is pumped from the bottom of the flash vessel with a gear pump or other suitable pump for viscous materials. Critical to operation of the flash devolatilization unit is prevention of air back into the unit that reduces stripping ability and potentially allows oxygen into the unit that can discolor products or pose a safety hazard if low autoignition temperature solvents are used. Often one flash devolatilization unit is insufficient to reduce the residual material to a sufficient level and thus additional units can be added in series [61]. In each vessel, the equilibrium concentration of volatile material in the polymer melt, is a function of the pressure and temperature the flash unit operates at, with consideration for the polymer solvent interaction effects described by the Hory-Huggins equation. Flash devolatilization units, while simple to operate, may be prone to foam development as the superheated volatiles rapidly escape from the polymer melt. Viscous polymers or polymers with mixed functionalities... 

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