Ignition mixtures

Flash point. The flash point of a liquid is the lowest temperature at which it gives off enough vapor to form an ignitable mixture with air. The flash point generally increases with increasing pressure. 

The flash point is the lowest temperature at which a liquid gives off sufficient vapor to form an ignitable mixture with air near the surface of the liquid or within the vessel used. ASTM test methods include procedures using a closed cup (ASTM D56, ASTM DOS, and ASTM D3828), which is preferred, and an open cup (ASTM D92 and ASTM D1310). When several values are available, the lowest temperature is usually taken in order to assure safe operation of the process. 

The flash point represents the minimum temperature at whieh an ignitable mixture exists above a liquid surfaee. By definition, flash points are inapplieable to gases. Some solids, e.g. naphtlialene and eamphor, are easily volatilized on heating so that flammable mixtures develop above the solid surfaee and henee flash points ean be determined. (However, although these substanees ean be ignited, they generally need to be heated above their flash points in order for eombustion to be sustained this is the fire point .)... 

Flashpoint — the lowest temperature of a liquid at whieh it gives off enough vapor to form an ignitable mixture with air near the surfaee of the liquid within the vessel used. Two tests are used—Open Cup and Closed Cup. Generally, the Open Cup method results in flashpoints 5° to 10° higher than the Closed Cup method. Flashpoint < 140°F (Closed Cup) is the eriterion used by EPA to deeide whether a ehemieal is hazardous by ignitability. DOT defines materials with flashpoints of < 100°F as flammable materials, and between 100° and 200°F as eombustible. 

Cbemical Reactivity - Reactivity with Water Reacts violently with liberation of heat and oxygen and the formation of caustic solution Reactivity with Common Materials Forms e qtlosive and self-igniting mixtures with wood and other combustible materials Stability During Transport Stable if kept dry Neutralizing Agents for Acids and Caustics Following the reaaion with water, the caustic solution formed can be flushed away with water and area rinsed with dilute acetic acid Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Flammable gases and vapors or combustible dust may be present in quantities sufficient to produce explosive or ignitable mixtures due to ... 

Consideration shonld also be given to the possibility that the flame arrester may ping, which conld prodnce a vacnnm condition in a low-pressnre tank when the tank is primped out, and implode (collapse) the tank. This may reqnire the installation of a vacnnm breaker or a pressnre-vacnnm conservation valve. If the tank contents are flammable and admission of air may resnlt in an ignitable mixture, it may be necessary to install an inert gas blanketing system on the tank, actuated by a pressnre controller, which would admit a sufficient flow of inerting gas when a vacnnm condition is detected. 

Class I Locations. Class I locations are those in which flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures. Class I locations shall include those specified in (a) and (b) below. 

Care must be taken in weighing out and transferring the catalyst as it can ignite mixtures of air and flammable vapors. The operation of the Parr apparatus and appropriate safety precautions in its use have been described in detail.2... 

The carbonyl on exposure to atmospheric oxygen produces a deposit which becomes peroxidised and may ignite. Mixtures with air or oxygen at low partial and total pressures explode after a variable induction period [1]. Addition of the carbonyl to a butane-oxygen mixture at 20-40°C caused explosive reaction in some cases [2], See other induction period incidents... 

Minimum ignition temperature of a dust cloud (MITc) The lowest temperature of a hot surface on which the most ignitable mixture of the dust with air is ignited under specified test conditions. 

The lowest temperature of a flammable liquid at which it gives off sufficient vapor to form an ignitable mixture with the air near the surface of the liquid or within the vessel used. The flash point has been commonly determined by the open cup or closed cup method but recent research has yielded higher and lower flash points dependent on the surface area of the ignition source. Because of this aspect ASTM and other standard test methods have been recently withdrawn. They are under review until an adequate determination of a practical and comprehensive standard is composed and agreed upon. 

Kerosene or sometimes referred to as Fuel Oil 1 is a refined petroleum distillate. Kerosenes usually have flash points within the range of 37.8 °C to 54.4 °C (100 °F to 130 °F). Therefore unless heated, kerosene will usually not produce ignitable mixtures over its surface. In atmospheric burning smoke production normally occurs. It is commonly used as a fuel and a solvent. In some applications it is treated with sulfuric acid to reduce the content of aromatics, which bum with a smoky flame. 

Electrical energy discharged from a capacitor, which is just sufficient to effect ignition of the most ignitable mixture of a given fuel-mixture under specific test conditions. 

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