Flame spread index

Antimony oxide and 2inc borate are also used as synergists for unsaturated polyesters. Their combined effect on the flame spread index (25) is ... 

The surface burning characteristics (flame spread index and smoke developed index) for wood and wood products as measured by American Society for Testing and Materials (44) can be reduced with fire retardant treatments, either chemical impregnation or coatings (48). Fire retardant treatments also reduce the heat release rate of a burning piece of wood (49,50). The heat release rates (51) of the burning materials are an important factor in fire growth. 

Eickner and Schaffer (10) found that monoammonium phosphate (Figure 2) was the most effective of different fire-retardant chemicals in reducing the flame-spread index of Douglas-fir plywood. They used the 8-foot tunnel furnace of ASTM E286 (37). 

The untreated plywood had a flame-spread index of 115. This was reduced to about 55 at a chemical retention of 2 pounds per cubic foot, to 35 at 3 pounds, 20 at 4 pounds, and to about 15 at retentions of 4.5 pounds and higher. Zinc chloride was next in effectiveness but required higher retention levels to reduce the flame-spread index values equivalent to monoammonium phosphate. 

A retention of 6 pounds per cubic foot reduced the flame-spread index of the plywood to only 60. 

The laminate construction in FRP parts can have an effect on flame spread and smoke test results. A study was conducted by Stevens15 and published in the proceedings of Composites 2007 conference. This study looked at how glass fiber content and panel thickness affected the ASTM E-84 flame spread index (FSI) and smoke developed index (SDI). The effects of fiber content and thickness on cone calorimeter results were also evaluated. Another study was conducted by Dempsey16 looking at the effect of glass content in several fire tests, and in this paper, he also found a correlation between the FR performance and glass content. 

Figure 4. Effect of inorganic additives on flame-spread index, measured...

Organophosphorus and polyphosphate compounds also have been used as fire retardants. In one study, ammonium polyphosphate was used at loading levels of 96 kg/m to achieve a flame-spread index of 15 according to ASTM E 84 (J2). This treatment produced low smoke yields however, this treatment was corrosive to aluminum, slightly corrosive to mild steel, but not corrosive to brass (77). In a patent by Clermont (78), phosphorus pentoxide, dimethylformamide, and urea were used to produce fire-retardant paper or veneer. Other patents (79, 80) describe the reaction of ammonia with partial esters of polyphosphoric acid. All patents demonstrated some leach resistance of the phosphorus. 

Basic Mechanisms. Finally, further work is necessary on fundamental mechanisms of individual fire retardants. These mechanisms are a function of the particular chemicals involved and the environmental conditions of the fire exposure. There is a need to establish common methods and conditions for determining these mechanisms in order to compare different treatments. This would give us a better understanding of how these compounds work in action and would provide a more efficient approach for formulating fire-retardant systems than a trial and error approach. Correlations also need to be established between rapid precise thermal analysis methods and standard combustion tests. Retardant formulations could be evaluated initially on smaller (research and development size) samples. The more promising treatments could be tested for flame-spread index, heat release rate, and toxic smoke production. 

ASTM D 3675 Surface Flammability of Flexible Cellular Materials Using a Radiant Heat Energy Source This method may be used on cellular elastomeric materials such as flexible polyurethane foam and neoprene foam. It employs a radiant panel heat source consisting of a 300 by 460-nun (12 by 18 in.) panel in front of which an inclined 150 by 460-m (6 by 18 in.) specimen of the material is placed. The orientation of the specimen is such that ignition is forced near its upper edge, and the flame front progresses downward. Factors derived from the rate of progress of the flame front and heat liberated by the material under test are combined to provide a flame spread index. The method was developed to test cellular elastomeric materials which could not be tested by ASTM E 162. 

This is called the Radiant Panel Test. A Flame-Spread Index is calculated as a product of the flame-spread and heat-evolution factors. Smoke density is also obtained. 

ASTM E84-00a)a Flame spread index = 10 Smoke development index = 15... 

Fire tests in a 25-foot tunnel furnace were carried out according to standard ASTM E84 by the Underwriters Laboratory and the Hardwood Plywood and Veneer Association. Results are given for the flame spread index (FSI) and smoke developed index (SDI). The values obtained from burning the test materials represent a comparison with that of Va inch inorganic reinforced cement board expressed as zero and red oak flooring expressed as 100. 

Flammability of materials is characterized by many different ways, one of them is the flame spread index (FSI). As reference values, FSI for inorganic reinforced cement board surface is arbitrarily set as 0, and for select grade oak surface as 100 under the specified conditions. FSI for ordinary wood species is typically between 100 and 200, and for some special cases it is as low as 60-70. An average FSI for about 30 different wood species is 125 45. 

Both ordinary wood species and most of WPC deck boards belong to Class C category of flammability in terms of flame spread. There are four basic categories, or classes, for flame spread index Class A, with FSl between 0 and 25 Class B, with FSl between 26 and 75 Class C, with FSl between 76 and 200 and below Class C, with FSl above 200 (unclassified materials). Classes A, B, and C sometimes are called Classes 1,11, and 111. 

Because fly ash is not a real, active flame retardant, plastics filled with it typically have practically the same ignition point and only slightly higher flame spread index compared to the neat plastic. 

TABLE 14.1 ASTM E 84 flame spread indexes for 19-mm-thick solid lumber [1]... 

Species Flame spread index Smoke developed index... 

FLAME SPREAD INDEXES AND FIRE RATING OF COMPOSITE MATERIALS... 

Class A Flame spread index 0-25 Class B Flame spread index 26-75 Class C Flame spread index 76-200... 

TABLE 14.4 Flame spread indexes for commercial WPCs determined according to ASTM E 84... 

Deck boards (solid or hollow) Profile Manufacturer Principal ingredients Flame spread index... 

Note 1 ASTM s policy is not to use descriptive terms such as nonflammable, flame retardant, self-extinguishing, non-burning, and similar. According to ASTM, results of any of fire test methods must be described in numbers, such as flame spread index of 75, or flame spread index below 200, or a burning rate of... 

TABLE 14.13 Flame spread index (FSI). Within-laboratory and between-laboratory data... 

TABLE 14.14 Flame Spread Index (ESI), Flame Spread Factor (FSF), and Heat of evolntion valnes (determined according to ASTM E 162) for two HDPE-based composite materials, one filled with rice hulls, another with rice hulls and a mineral filler. Detailed on the compositions are given on page 484. Data by the author. 

Class A, B, C flame spread index, 36, 462 Class I, II, III flame spread index, 36... 

Flame spread index (FSl), 35, 36, 59, 461, 464, 480, 481 Calculation, 481 HDPE-based boards, 36 Hollow boards, 36... 

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