Flammable range, fires

Conclusions The use of an inert atmosphere can virtually eliminate the possibility of explosions and fire with flammable materials. However, inerting systems can be quite expensive and difficult to operate successfully and can be hazardous to personnel. Before using inert systems, alternatives should be explored, such as using nonflammable materials or operating below the flammable range. 

Flammability Range - Defined as the difference between the UEL and LEL. This difference is an indication of how wide the flammability limits of a chemical are. The wider this range, the more hazardous the chemical may be considered from a fire standpoint. 

Ignition Temperature - This is defined as the minimum temperature at which a chemical substance will ignite without a spark or flame being present. Along with the values of flash point and flammability range, it provides and indication of the relative fire potential for the chemical. 

Vinyl chloride also poses a significant fire and explosion hazard. Tt has a wide flammability range, from 3.6% to 33.0% by volume in air. Large fires of the compound are very difficult to extinguish, while vapors represent a severe explosion hazard. 

Zert-Butyl methyl ether, now manufactured in bulk as a gasoline component, is a less hazardous extracting solvent than diethyl ether, as it scarcely forms peroxides, is less volatile (b.p. 55°C) and has a narrower flammable range (2.5-15%) in air [1]. However, fires involving it are difficult to extinguish with foam, as no film-forming elfect is shown [2]. 

Flammability Flammability hazard is concerned with the ease with which materials can be ignited and continue to bum. A major consideration is the rate of burning. Clouds of fine combustible dusts, for example, bum so rapidly that they have the force and effect of an explosion. There are various criteria which have been developed to identify flammable materials. Flash points, fire points, and autoignition temperature are 3 common measures of flammability. Flame propagation and the explosive or flammable range are measures commonly used for gases, vapors and air-suspended fine combustible dusts. PSTofbric materials are included in this class. 

Flammability Hazards—several endpoint criteria are used. For flammable liquids that form large pool fires, a steady heat load or thermal radiation criterion often expressed in BTU/hr-ft or kW/m is used. For determining hazards from short-duration BLEVEs and fireballs, an integrated dose criterion, which represents the area of a time-dependent heat flux, is used. For determining flash fire hazards, a flammable vapor has to be diluted to within its flammable range, with the concentration often usually expressed in ppm, mg/m, or as a volume percent. 

Turbulence is required for the acceleration of flame front to speeds required to produce the blast overpressure associated with a VCE. In the absence of turbulence, a flash fire will occur without any appreciable overpressure, with the hazard limited to the thermal radiation impacts associated with the burning of the cloud from the ignition point back to the release source, or within the flammable range of the cloud. Flame turbulence is typically formed by the interaction between the flame front and obstacles. The blast effects produced by VCEs vary greatly and are primarily dependent on flame speed therefore, areas of confinement and congestion near the release point can influence the likelihood of a VCE. Additionally the reactivity of the material is an important consideration highly reactive materials such as ethylene oxide are much more likely to lead to a VCE than lower reactive materials such as methane. 

Physical changes involve changes in the physical state of the chemical, bnt do not produce a new substance, snch as the physical transformation from a liqnid to a gas or a liquid to a solid. Physical properties include specific gravity, vapor pressure, boiling point, vapor density, melting point, solubility, flash point, fire point, auto-ignition temperatnre, flammable range, heat content, pH, threshold limit valne (TLV), and permissible exposnre level (PEL). 

The carbon and the sulfur atoms are satished. The compound formed is carbon disulhde, which is a poison by absorption it is a highly flammable, dangerons fire and explosion risk, has a wide flammable range from 1 to 50%, and can be ignited by friction. Carbon disulfide also has a low ignition temperature and can be ignited by a steam pipe or a light bulb. 

Propane and butane are two conunon 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 temperature 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. 

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