Fire source

Factory Mutual Corner Test. This is a large-scale comer test used to test building products (18—20). The test rig consists of three sides of a cube. The two walls are 15.24 and 11.58 m by 7.62 m tall. The ceiling is 9.14 x 15.24 m. The product to be tested is mounted on the walls and ceilings ia a manner consistent with the iatended use. The fire source is a 340 kg stack of wood pallets located ia the corner. In order to pass the test, no flame can propagate to any extremity of the walls or ceiling. The Factory Mutual flammabiHty apparatus is proposed to replace this test for certain appHcations (21). 

CAL 133. California Technical Bulletin 133 is a test of the fire hazard associated with upholstered furniture (22). The test is carried out by igniting a standard fire source directiy on the piece of furniture being tested. In the most recent version of the test, the fire source is a gas flame. Smoke, heat, and toxic gas emissions are measured dufing the test. A related test, BS 5852, uses various wooden cribs as the fire source (23). 

Flammability. The results of small-scale laboratory tests of plastic foams have been recognized as not predictive of their tme behavior in other fire situations (205). Work aimed at developing tests to evaluate the performance of plastic foams in actual fire situations continues. All plastic foams are combustible, some burning more readily than others when exposed to fire. Some additives (131,135), when added in small quantities to the polymer, markedly improve the behavior of the foam in the presence of small fire sources. Plastic foams must be used properly following the manufacturers recommendations and any appHcable regulations. 

Fig. 6-2, Uncontroiled forest fire. Source Information and Education Section, Oregon Department of Forestry.

There are many types of detection and suppression systems. The one selected should be compatible with the likely fire source and be consistent with the likely locations and fire size within the building. 

These intumescent coatings, when subjected to fire, form a char between the substrate and the fire source. The basic product coated becomes flameproof (36,159). 

The solutions in Table 10.1 were fitted to data by Yokoi [3] from small fire sources with an estimation of XT, the radiation fraction, for his fuel sources. Fits by Zukoski [8], without accounting for radiation losses (Xr = 1), give values of < , 0.11 and (3 = 0.91... 

Let us examine some alternative results and consider the effects of the base fire dimension D. Measurements are given by Yokoi [3] for fire sources of Figure 10.9 and 20 cm radius (r0 = D/2). The temperature profiles... 

Finite Fire Sources Dimensionless Temperature,

Continuous heat source, r0 = 9.,9 cm o Discontinuous heat source, r0 = 20 cm... 

Figure 10.9 Dimensionless temperature profiles, (T — 7 00)/(7 m — Too), for finite fire sources (from Yokoi [3])...

A steel sphere is placed directly above a fire source of 500 kW. The height of the sphere is 3 m. Its properties are given below ... 

Detectors with complete black body rejection capability are usually less sensitive to fires than a single frequency infrared optical detector. Because it s discrimination of fire and non-fire sources depend upon an analysis of the ratio between fire and reference frequencies, there is a variation in the amount of black body rejection achieved. A detector s degree of black body radiation rejection is in inversely proportion to its ability to sense a fire. The detectors are limited to applications that involve hydrocarbon materials. 

When determining flame height, an assumption that the flame is a solid gray emitter with a well-defined cylindrical shape is made for ease of calculation. The cylinder may be straight or tilted as a result of wind. For pool fires, the flame height above the fire source can be determined by (Heskestad, 1981 1983) ... 

These battery-limit, unit isolation valves should be clearly identified and installed in easily accessible locations that are a safe distance from potential fire sources. Generally, 25-50 ft (8-15 m) provides an acceptable separation distance. These isolation valves can also be used for turnaround purposes and should be located at or near ground level. 

Where process equipment is provided with fixed-temperature detectors, these should be located as near as possible to the potential fire source for example, above flammable liquid pump seals, immediately over a solvent draw-off point, or mounted above a crude tank mixer stuffing box. As a general rule, fixed-temperature detectors directed at a potential hazard should be considered only for process equipment where specific fire problems are anticipated. 

Special grades of polystyrene include impact polystyrene modified with ignition-resistant chemical additives. These were developed because of increased emphasis on product safety and used in many electrical and electronic appliances. The addition of flame-retardant chemicals docs not make the polymer noncombustible, but increases its resistance to ignition and decreases the rate of burning when exposed to a minor fire source. 

Fire-resistant walls are an adequate barrier to exclude a building from fire exposure penalties if the fire source is external. However, a fire-resistant wall is not an adequate barrier where an explosion hazard exists. 

The heat from the fire source and the upper layer determines the time when conditions become untenable inside the compartment and consequently the duration for safe egress.9... 

The tendency of a material to spread a flame away from the fire source is critical to understand the potential fire hazard. Flame-spread tests may refer to organic polymers themselves or to materials in diverse applications (such as textiles or electrical insulation sleeving), or to whole structures... 

Byram and Martin [97] used external vertical cylinders with tangential slots oriented to produce rotating flow about a fire source. They examined two sets of equipment of diameters and heights, 33 and 183 cm, or 66 and 335 cm, respectively. Burning alcohol pools within their apparatus, they reported visible fire whirls up to 300 cm tall with inner fire tube columns 2 cm in diameter. They observed horizontal velocities at the surface of the inner column of about 9 m/sec ( 6000 rpm) and vertical velocities to 18 m/sec. 

The second, more empirical path, is marked by the development of larger scale test methods that are meant to simulate potential "real world" or actual exposure conditions. Examples of such test methods are room fire tests in which actual pieces of furniture are placed in 8 x8 xl2 room-size enclosures and exposed to fire sources ranging from multiple sheets of newspaper or waste baskets in full conflagration to even larger sources such as 20 lb. and 25 lb. wood cribs. 

Shuklin, S.G. Kodolov, V. L Larionov, K. I. Tyurin, S. A. Physical and chemical processes in modified two-layer fire and heat-resistant epoxy-polymers under the action of fire sources Physics of combustion and explosion. 1995. V. 31.-Iss. 2.-P. 73-79. 

Toxicology LD50 (parenteral, mouse) 2 g/kg hannful if swallowed si. toxic by parenteral route primary irritant severely imtating to eyes and skin corrosive causes bums cancer suspect possible teratogen avoid contact and inh. TSCA listed Precautkm Combustible liq. dangerous fire risk risk of explosion by shock, friction, or fire source powerful oxidizer Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and irritating vapors... 

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