Upper flash-point

Fig. 1. Effect of temperature on limits of flammabiUty of a pure Hquid fuel ia air, where = lean (or lower) flash point = rich (or upper) flash point ...

The Japanese have started to measure the temperature corresponding to a composition of the upper explosive limit of a vapour in air under the name Upper Flash Point. Some examples are given [20],... 

The foregoing results refer to what may be termed the lower flashpoint, that is, the temperature of inflammation when the combustible vapour is present in sufficient quantity to reach the lower limit. There is a corresponding upper flash-point, which is seldom referred to and which may be determined by sparking in a more or less confined space. It represents the temperature of inflammation of the vapour at its higher limit.4... 

The lower explosive limit (LED of a solvent corresponds to the vapour concentration above the liquid at its flash point at which a source of ignition will set off an explosion. The upper explosive limit (DEL) is the vapour concentration that is just too rich to explode and an upper flash point of a pure solvent can be calculated if the DEL and the Antoine constants are known. 

Compound Lower Upper Flash Point, °C Boiling Point, °C Temperature, °C (Average), % v/V"... 

Flash points and autoignition temperatures are given in Table 11. The vapor can travel along the ground to an ignition source. In the event of fire, foam, carbon dioxide, and dry chemical are preferred extinguishers. The lower and upper explosion limits are 1% and 7%. 

Flammability Acrolein is very flammable its flash point is <0° C, but a toxic vapor cloud will develop before a flammable one. The flammable limits in air are 2.8% and 31.0% lower and upper explosive limits, respectively by volume. Acrolein is only partly soluble in water and will cause a floating fire, so alcohol type foam should be used in firefighting. The vapors are heavier than air and can travel along the ground and flash back from an ignition source. 

The relatively low flash points of some acrylates create a fire hazard. Also, the ease of polymerization must be home in mind in ah. operations. The lower and upper explosive limits for methyl acrylate are 2.8 and 25 vol %, respectively. Corresponding limits for ethyl acrylate are 1.8 vol % and saturation, respectively. All possible sources of ignition of monomers must be eliininated. 

Pentane Bp, °C Flash point, °C Ignition temperature, °C Lower Upper... 

Compound Flash point, °C Flammability limit, vol % Lower Upper Autoignition temperature, °C... 

Because biphenyl is often transported in the molten state, a moderate fire ha2ard does exist under these circumstances. Biphenyl, with a flash point of 113°C, has a lower flammability limit of about 0.6% (by volume) at the flash point to an upper limit of 5.8% at 166°C (42). Dust explosions are a ha2ard when vapors from a hot Hquid surface condense in air in a confined space. 

Flash point, °C Autoignition temperature, °C lower upper... 

Flash points, lower and upper flammability limits, and autoignition temperatures are the three properties used to indicate safe operating limits of temperature when processing organic materials. Prediction methods are somewhat erratic, but, together with comparisons with reliable experimental values for families or similar compounds, they are valuable in setting a conservative value for each of the properties. The DIPPR compilation includes evaluated values for over 1000 common organics. Detailed examples of most of the methods discussed are available in Danner and Daubert."... 

The upper and lower flammabihty limits are the boundary-line mixtures of vapor or gas with air, which, if ignited, will just propagate flame and are given in terms of percent by volume of gas or vapor in the air. Each of these limits also has a temperature at ch the flammabihty limits are reached. The temperature corresponding to the lower-hmit partial vapor pressure should equal the flash point. The... 

Chemical compound Flam, limits, lower, % v/v Flam, hmits, upper, % v/v Autoignition temperature. Flash point, closed cup. Flash point, open cup. 

Important flammability characteristics are the lower and upper flammability limits, the flash point, the minimum ignition energy, the minimum oxygen concentration, and the autoignition temperature. Values of some of these properties are published for many compounds (NFPA, 1994). These numbers have typically been developed under standardized test conditions. Process conditions may influence their values. 

Tlie remainder of tliis cliapter provides information on relative physical properties of materials (flash points, upper and lower explosive limits, tlireshold limit values, etc.) and metliods to calculate tlie conditions tliat approach or are conducive to liazardous levels. Fire liazards in industrial plants are covered in Sections 7.2 and 7.3, and Sections 7.4 and 7.5 focus on accidental explosions. Sections 7.6 and 7.7 address toxic emissions and liazardous spills respectively. tliese latter types of accident frequently result in fires and explosions tliey can cause deatlis, serious injuries and financial losses. 

Tl = equilibrium temperature at which the lower flammable limit composition exists over liquid in dry air at one atmosphere (theoretical flash point), °C or °F Ty = equilibrium temperature at which the upper flammable limit composition exists over liquid in dry air at one atmosphere, °C or °F... 

The figures for flash points are closed-cup values except where a suffix (o) indicates the (usually higher) open-cup value. The figures for explosive limits (or flammability limits) are % by volume in air at ambient temperature except where indicated otherwise. Where no figure has been found for the upper limit, a query has been inserted. Figures for auto-ignition temperatures are usually those determined in glass (without catalytic effects) except where stated. 

FLASH POINT (METHOD USED) Did not flash to 280 DEG F FLAMMABLE LIMIT Not applicable LOWER EMPLOSIVE LIMIT Not available UPPER EXPLOSIVE LIMIT Not available... 

There are several standard tests for determining the flammability of materials (ASTM, 2004). For example, the upper and lower concentration limits for the flammability of chemicals and waste can be determined by standard test methods (ASTM D4982, E681), as can the combustibility and the flash point (ASTM D1310, E176, E502). With these definitions in mind it is possible to divide ignitable materials into two subclasses ... 

Upper explosive limit The maximum concentration (vol % in air) of a flammable gas or vapor required for ignition or explosion to occur in the presence of anignition source (see also Flash point). 

After the initial test to determine the approx flash point of the material, repeat the procedure by cooling a fresh portion of the sample, the glass cup, the bath solution, and the thermometer to more than 20F(11C) below the approx flash point. When the temp of the sample is exactly 20 F below the approx flash point, the center of the liquid level should be adjusted to l/8 inch (3.2mm) below the upper edge of the cup as determined with the leveling device placed across the diam... 

Stability. Highly flammable flash point, 20 °C (closed cup) (Budavari, 1998) explosive limits, 12.4% (upper), 1.8% (lower) by volume in air (American Conference of Governmental Industrial Hygienists, 1999)... 

Flammable Limits in Air — The percent concentration in air- (by volume) is given for the lower (LFL) and upper (UFL) limit. The values, along with those for flash point and ignition temperature, give an indication of the relative flammability of the chemical. The limits are sometimes referred to as "lower explosive limit (LEL) and "upper explosive limit" (UEL). Chapter 3 provides a detailed technical explanation. 

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