Spreading-test

Tunnel Test. The tunnel test is widely used to test the flame spread potential of building products such as electrical cable (15) and wall coverings (16). The test apparatus consists of a tunnel 7.62 x 0.445 m x 0.305 m ia cross section, one end of which contains two gas burners. The total heat suppHed by the burners is 5.3 MJ/min. The test specimen (7.62 m x 50.8 cm), attached to the ceiling, is exposed to the gas flames for 10 minutes while the maximum flame spread, temperature, and smoke evolved are measured. The use of this and other flame spread test methods has been reviewed (17). 

Long Jr, R.T., An evaluation of the lateral ignition and flame spread test for material flammability assessment for micro-gravity environments, MS Thesis, Department of Fire Protection Engineering, University of Maryland, College Park, Maryland, 1998. 

The results of semi-quantitative charge spreading tests suggests that the lateral conductance of polyimide-field oxide interfaces can be sufficiently low to permit reliable device operation. This topic must be addressed in the context of the overall processing of the interface, including any adhesion promoters used. 

In many laboratories, flame-spread tests of different types have consistently shown that the current acceptable treatments will... 

The UL 94 standard specihes bench-scale test methods to determine the acceptability of plastic materials for use in appliances or other devices with respect to flammability under controlled laboratory conditions. The test method that is used depends on the intended end-use of the material and its orientation in the device. The standard outlines two horizontal burning tests, three vertical burning tests, and a radiant panel flame spread test. The most commonly used test method described in the UL 94 standard is the 20-mm Vertical Burning Test V-0, V-l, or V-2. The method is also described in ASTM D 3801. A schematic of the test setup is shown in Figure 14.3. 

Lateral Ignition and Flame Spread Test (ASTM E 1321)... 

The Lateral Ignition and Flame spread Test (LIFT) apparatus was developed primarily for lateral flame spread measurements. The apparatus, test procedures, and methods for data analysis are described in ASTM E 1321. A sample of 155 x 800 mm is exposed to the radiant heat of a gas-tired panel. The panel measures 280 x 483 mm. The heat flux is not uniform over the specimen, but varies along the long axis as a function of distance from the hot end as shown in Figure 14.6. The flux distribution is an invariant of distance when normalized to the heat flux at the 50 mm position. When methane or natural gas is burnt, the upper limit of the radiant heat flux is 60-65 kW/m2. The lower limit is approximately 10kW/m2 since the porous ceramic tile surface of the panel is only partly covered with flame at lower heat fluxes. 

In flame spread tests, the specimen is ignited at the hot end by a nonimpinging premixed acetylene-air pilot flame. Flame spread rate over the surface is then monitored as a function of distance x. Thus, one experiment yields information on flame spread rate over a whole range of heat flux levels (or surface temperatures). Information to this extent can be obtained in one run owing to the particular shape of the flux invariant, which is the result of the specific geometry and specimen-panel arrangement shown in Figure 14.7. 

Conceptually, there are two types of flame spread tests. The length of the specimen is generally much greater than the width and flame propagation is measured in the direction of the longest dimension. In the first type of flame spread tests, the specimen is exposed to a gas burner flame at one end. In the second type, the specimen is exposed to a radiant panel producing a heat flux that varies from one end of the specimen to the other. A pilot flame is used to ignite the specimen at the hot end. An example of each of the two types is described as follows. 

As mentioned earlier, the fire hazard of interior finish materials is primarily due to the potential for rapid wind-aided flame spread over the surface. It is therefore not a surprise that reaction-to-fire requirements for interior finish materials in U.S. building codes are primarily based on performance in a wind-aided flame spread test. The apparatus of this test is often referred to as the Steiner tunnel. The Steiner tunnel test is described in ASTM E 84. Although the test does not measure any material properties that can be used in a model-based hazard assessment, a discussion of the test is included here due to its practical importance for the passive fire protection of buildings in the United States. 

FIGURE 21.9 Lateral ignition and flame spread test. 

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... 

Hirschler, M.M. and Piansay, T., Survey of small scale flame spread test results of modern fabrics, Fire Mater., 31, 373-386 (2007). 

EN 50399, Common test methods for cables under fire conditions—Heat release and smoke production measurement on cables during flame spread test—Test apparatus, procedures, results, European Committee for Standardization, Brussels, Belgium. 

Motor vehicles Most of the passenger car interiors including car seats are made of polyester fiber (90% of the world market), and in some cases polypropylene fiber. The flammability testing of fabrics used in motor vehicles, in particular, cars are not mandatory due to the fact that fire incidents in motor vehicles are rare and, moreover, fire spreads relatively slowly. Most manufacturers test seating covers and carpets conform to the U.S. FMVSS (Federal Motor Vehicle Safety Standard) 302 test, which is a simple horizontal flame spread test. Other similar standards are German DIN 75 200, British, Australian BS AU 169, and Japanese JIS D 1201 automotive standards. The curtains and blinds are tested according to tests specific to them discussed earlier. 

FIGURE 24.7 (See color insert following page 530.) Flame spread test of PP using BS 5438 Test 1 rig. 

Tunnel Flame-Spread Tests. The growth of a small fire in a building is influenced by the rate at which flames spread over the... 

Figure 2. Underwriters Laboratory s 25-ft tunnel flame-spread test.

No differences in flammability characteristics between the 0.1% Cu20-treated and untreated flexible polyurethane foam were observed. These characteristics were examined to assure that the positive effect on toxicity was not contradicted by negative effects on the flammability properties. The flammability characteristics examined were (1) ignitability in three systems (the NIST Cup Furnace Smoke Toxicity method, the Cone Calorimeter, and Lateral Ignition and Flame Spread Test (LIFT)), (2) heat release rates under small-scale (Cone Calorimeter) and medium-scale (furniture calorimeter) conditions, (3) heats of combustion under small-scale (Cone Calorimeter) and medium-scale (furniture calorimeter) conditions, (4) CO/CO2 ratios under small-scale (Cone Calorimeter) and medium-scale (furniture calorimeter) conditions, (5) smoke obscuration (Cone Calorimeter), and (6) rate of flame spread (LIFT). 

BS 5438, with its counterparts BS EN ISO 6940 [55] and 6941 [56], is probably the most widely used small flame test for textiles, and its various parts are used for both ignition and flame spread tests. It is more convenient first to consider the British Standard in its original form before the introduction of the ISO and EN tests and speci-... 

BS 5438 was amended in 1990, and sections dealing with the determination of the minimum ignition time (Tests lA and IB) and the flame spread (Tests 3A and 3B) were incorporated into similar specifications such as BS EN ISO 6940 [55] and BS EN ISO 6941 [56]. The test to determine minimum ignition time is given in BS EN ISO 6940 and flame spread in BS EN ISO 6441. The face ignition procedure for limited flame spread (Test 2A) was used as BS EN 532 [57], It is anticipated that these standards will eventually be... 

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