Open Cup flash point

In the laboratory, excess reagent in a product should be destroyed before workup. Addition of diluted aqueous ammonia is the most effective practice, if ammonia is otherwise acceptable. Combustibility is a minor problem. The open-cup flash point of 116°C for dimethyl sulfate is well above normal handling temperatures. Elammable, toxic vapors are given off at elevated temperatures. 

Product open cup Flash point, °C closed cup Fine point, °C open cup... 

Fire point The lowest temperature at which a liquid in an open container will give off enough vapors to continue to burn when once ignited [32]. This temperature is generally somewhat above the open-cup flash point. 

There are several different experimental methods used to determine flash points. Each method produces a somewhat different value. The two most commonly used methods are open cup and closed cup, depending on the physical configuration of the experimental equipment. The open-cup flash point is a few degrees higher than the closed-cup flash point. 

The problem with open-cup flash point procedures is that air movements over the open cup may change the vapor concentrations and increase the experimentally determined flash point. To prevent this, most modern flash point methods employ a closed-cup procedure. For... 

Figure 6-3 Cleveland open-cup flash point determination. The test flame applicator is moved back and forth horizontally over the liquid sample.

Standardized test using a small quantity of liquid that is slowly heated until a flash is observed when an open flame is dipped down into a covered vapor space. Flash point temperatures are normally given as open cup or closed cup, based on the type of apparatus used to measure the flash point. The open cup flash point is normally a few degrees above the closed cup flash point. 

From the point of view of the potential for a fire, the closed cup flash point determination is usually the most important. In a perfect closed cup test, the vapor pressure is in equilibrium with the liquid at the temperature of the test. At the flash point, the vapor composition is at the lower flammable limit. In fact, the lower flammable limit can be estimated from vapor pressure data (for a pure compound). Open cup flash points are generally higher and, thus less conservative, than closed cup determinations. The value determined in an open cup test is subject to air movement at the open face of the cup and true vapor-liquid equilibrium probably does not occur. 

Flash points of mixtures of oxygenated and hydrocarbon solvents cannot be predicted simply. A computer based method is proposed which exhibits satisfactory prediction of such Tag Open Cup flash points. Individual solvent flash point indexes are defined as an inverse function of the component s heat of combustion and vapor pressure at its flash point. Mixture flash points are then computed by trial and error as the temperature at which the sum of weighted component indexes equals 1.0. Solution nonidealities are accounted for by component activity coefficients calculated by a multicomponent extension of the Van Laar equations. Flash points predicted by the proposed method are compared with experimental data for 60 solvent mixtures. Confidence limits of 95% for differences between experimental and predicted flash points are +8.0-+3.0°F. 

CHEMICAL PROPERTIES stable under ordinary conditions of use and storage hazardous polymerization will not occur resistant to acids and alkalies no open cup flash point to boiling reacts vigorously with strong oxidizers FP (NA) LFLAJFL (NA) AT (NA). 

Flammable liquids may not continue to bum after they have been ignited at their flash point. The temperature at which flammable liquids evolve vapours quickly enough to support sustained and continuous combustion is the fire point. A typical sample of No. 1 fuel oil may have a closed-cup flash point of 54°C, an open-cup flash point of 59°C, and a fire point of 63°C. See Terminology, Combustion, p.233 Terminology, Volatile, p.252. 

TEN tensile strength (usually Ts) TOC tangliabue open cup (flash point)... 

Contains 28% isopropyl alcohol and has a Tag Open Cup Flash Point of 85 °F. 

Fire point, ASTM open cup Flash point, Cleveland open cup Freezing point... 

In ignition test of petroleum products, solvents, resins, paints, adhesives, and other industrial combustible liquids, two methods are distinguished, viz. closed cup and open cup flash points. Besides the flash point (momentary flash), some standards permit the measurement of ignition point (continuous burning for 5 s or more) though the latter has less significance. 

The open cup flash point is usually determined by the Cleveland method (ISO 2592-1973, DIN ISO 2592-1981, ASTM D 92-1978, BS 4689 1980) when higher than 79 (Fig. 3.16a). The sample is filled into the open test cup to the filling mark... 

Correction terms for the determination of open cup flash point by the Cleveland method... 

Table 4.1 Closed cup and open cup flash point values for typical solvents...

The flash and fire points of petroleum products such as bitumens and bituminous binders, having an open cup flash point above 79 C, are determined by the Cleveland open cup apparatus. For fuel oils, the most common test method used is the closed cup procedure that uses the Pensky-Martens apparatus (see ISO 2719 2002 or ASTM D 93 2013). 

The fuel for a pool fire should comprise a distillate of petroleum with a distillation end point of 330°C maximum and an open cup flash point of 46°C minimum, and with a gross heating value of between 46 and 49 MJ/kg. This covers most hydrocarbons derived from petroleum with a density of less than 820 kg/m, e.g. kerosene and JP4 type fuels. A small amount of more volatile fuel may be used to ignite the pool as this will have an insignificant effect on the total heat input. 

Flash point The lowest temperature at which a liquid can evolve enough vapor to form a flammable mixture in air. There are two methods commonly used for determination of flash points, the open-cup and the closed-cup methods. The open-cup flash point is usually slightly higher than the closed-cup value. The closed-cup flash point for hydrocarbons can be approximated by... 

Some paints have a closed-cup flash point near room tenperature, whereas they have no measurable open-cup flash point. 

Figures in parenthesis, wherever given, represent the open cup Flash Point...

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