Flammability fire propagation

Techniques have been developed for the quantification of fire propagation using FMRC s Small-Scale Flammability Apparatus (A,6) and the National Institute of Standards and Technology (NIST) Flame Spread Apparatus (j J ). In this study, the FMRC technique was used. Oxygen Index and its dependency on temperature was used by AMTL to examine the fire propagation behavior of small samples of FRC materials (J 2). 

ASTM E 2058 Standard Test Methods for Measurement of Synthetic Polymer Material Flammability Using a Fire Propagation Apparatus. Annual Book of Standards, Vol. 04.07, ASTM International, West Conshohocken, PA. 

Tewarson A. Flammability parameters of materials—ignition combustion, and fire propagation. J. Fire Sci. 1994 12 329-356. 

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. 

Fire propagation. Combustion is initiated also in adjacent systems, by virtue of heat evolved in the fully developed fire. For this reason, the most important factor in fire-spread, besides the flammability and amount of plastics in the system, is the fire endurance of the system boundaries. Evolved heat, produced smoke and combustible gases are also as important as in the other stages. 

According to Webster s New World Dictionary Thesaurus the word flammable means easily set on fire that will bum readily or quickly term now preferred to INFLAMMABLE in commerce and industry. Easily set on fire refers to the ignition behavior, bum readily refers to the combustion behavior, and bum quickly refers to the fire propagation behavior of a material. Thus, flammability and fire behavior of materials are used synonymously when describing the ignition, combustion, and fire propagation behaviors of materials separately or in combination. 

The ignition, combustion, and fire propagation behaviors of polymer are examined in various flammability test standards, where polymers are intentionally degraded, and the degradation products are ignited and burned under controlled exposure and environmental conditions. Various countries and agencies promulgate these types of flammability test standards ... 

The NFPA 318 deals with the protection of clean rooms whereas the FMR 4910 and UL 2360 deal with the flammability of polymers for the clean rooms. In the FMR 4910 test standard, ASTM E2058 Fire Propagation Apparatus (FPA) [31] is used, whereas ASTM El354 Cone Calorimeter [36] is used in the UL 2360 test standard. Both test standards evaluate the fire propagation and smoke release behaviors of the polymers. Eor polymers for which fire propagation behavior cannot be defined clearly, both test standards use a large-scale parallel panel test [40, 63, 78]. Figures 11.12 and 11.13, discussed in an earlier section, illustrate the parallel panel test. 

Comparison of the flammability characteristics between the standard commodities and Li-ion batteries can only occur during the period where the fire did not propagate beyond the commodity of interest. Once the fire reaches the extent of the combustible commodity, the results can no longer be used to evaluate sprinkler response, since further fire propagation is not feasible. It is important to note that additional information regarding the overall fire hazard of each commodity can be obtained after the period of flammability characterization, in particular, the time of significant battery involvement. 

To understand the approaches for solving flammability and smoke issues, one must understand how a fire propagates. Fortunately, there are usually several pathways to achieve the desired fire ratings, and the reasons for and against each system will be discussed. The simplest way to show this is in the triangle of flame propagation (Fig. 9.3). All three aspects of this triangle must be present in the correct proportions... 

The autoignition temperature is the minimum temperature required for self-sustained combustion in the absence of an external ignition source. The value depends on specified test conditions. Tht flammable (explosive) limits specify the range of concentration of the vapor in air (in percent by volume) for which a flame can propagate. Below the lower flammable limit, the gas mixture is too lean to burn above the flammable limit, the mixture is too rich. Additional compounds can be found in National Fire Protection Association, National Fire Protection Handbook, 14th ed., 1991. 

Provide automatic sprinkler system/inerting gas Provide deflagration vents Provide deflagration suppression system Monitor flammable atmosphere/fire Provide nitrogen blocks (nitrogen injection to stop flame propagation) or other explosion isolation measures... 

Records show that more fatalities occur through victims being suffocated by smoke or poisoned by toxic gases emitted during a fire than by being burnt to death. This is particularly worrying when it is realised that many additives incorporated into a polymer to retard its flammability are often found to increase the amount of smoke emitted as the rate of flame propagation decreases. Most... 

A BLEVE involving a container of flammable liquid will be accompanied by a fireball if the BLEVE is fire-induced. The rapid vaporization and expansion following loss of containment results in a cloud of almost pure vapor and mist. After ignition, this cloud starts to bum at its surface, where mixing with air is possible. In the buoyancy stage, combustion propagates to the center of the cloud causing a massive fireball. 

Flash fire The combustion of a flammable gas or vapor and air mixture in which the flame propagates through that mixture in a manner such that negligible or no damaging overpressure is generated. 

Liquid Pool Flames. Liquid fuel or flammable spills often lead to fires involving a flame at the surface of the liquid. This type of diffusion flame moves across the surface of the liquid driven by evaporation of the fuel through heat transfer ahead of the flame. If the liquid pool or spill is formed at ambient conditions sufficient to vaporize enough fuel to form a flammable air/fuel mixture, then a flame can propagate through the mixture above the spill as a premixed flame. 

As you can see, it is important to plan the extent of the hazardous areas and various methods, such as fire walls, to prevent the transfer or propagation of volatile/flammahle materials from one plant area to another. When in douht, err on the side of being safe and conservative. Also keep in mind that dust can be just as hazardous as flammable liquids/ vapors and must be classified and handled accordingly. Tables 14-9 and 14-10 identify the NEMA Standard for Motors. ... 

Some materials may bum quite slowly but may propagate a flame rapidly over their surfaces. Thin wood paneling will burn readily, yet a heavy timber post will sustain a fire on its surface until it is charred, then smolder at a remarkably slow rate of burning. Bituminous materials may spread a fire by softening and running down a wall. Steel of course does not burn, but is catastrophically weakened by the elevated temperatures of a fire. PVC does not bum, but it softens at relatively low temperatures. Other plastics may not burn readily but still emit copious amounts of smoke. And some flammable plastics, such as... 

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