Flammability testing oxygen index test

Plastics—Multipurpose-Test Specimens Plastics—Determination of Flammability by Oxygen Index... 

The UL flammability ratings describe the relative ease of ignition and combustibiUty of plastics. Tests include the measurement of flame propagation, time to self-extinguish, melt and drip with and without flame, and oxygen indexes. Some engineering plastics, eg, polyetherimides, are, as ranked by this test, inherently nonflammable. Others can be made nonflammable by compounding with flame retardants (ERs) such as bromine... 

A third test often cited, Oxygen Index (O.I.) is an ASTM test which measures the flammability of the base polymers. The flammability of the polymer film may alone differ significantly from the flammability of the same polymer on a nonwoven substrate. Theoretically, the higher O.I. for a sample film, the higher its nonflammability. 

The performance of several latex binders in flame retardant testing of nonwoven polyester or rayon substrates with and without added flame retardants has been investigated. Correlation of coating flammability (i.e. by oxygen index) to actual performance on a substrate is poor. Results generated on both rayon and polyester... 

For thermoplastic composites, results of flammability tests are generally reported on the basis of oxygen index values and/or UL-94 ratings (e.g. (11-12). The general problems associated with composites and multicomponent systems have not been addressed in depth and published data pertain primarily to specific glass-filled resins offered by manufacturers, or to composite systems designed to meet the specifications of a particular end use. 

One of the most useful laboratory flammability tests is the oxygen index (Of) test (ASTM D-2043 and ASTM D-2863). In this test, the polymer is burned by a candle in controlled... 

There is evidence to show that the particle size of the filler also plays a significant role in flammability resistance. For example, below a certain particle size (about 1-2 pm), in many tests, including oxygen index, aluminum hydroxide shows enhanced fire-retarding performance,34 which may be associated with the rate of filler decomposition and/or with the formation of a more stable ash. However, it has been found that the particle size effect is absent, or less evident, in the cone calorimeter test.35 Similarly, particle size reduction has been shown to enhance fire retardancy in magnesium hydroxide-filled PP in this case, samples were characterized by the UL94 test.36 This raises the question as to whether further reductions in particle size to the nanoscale will lead to an additional increase in flammability performance, and perhaps enable filler overall levels to be significantly reduced. This aspect is considered in a later section. 

Isaacs JL. The oxygen index flammability test. J. Fire Flammability 1970 1 36-47. 

Wharton RK. The relative performance of critical oxygen index testing columns under ambient conditions. J. Fire Flammability 1981 12 266-271. 

Sevecek P, Filipi B, Zapletalova I. Modification of the oxygen index test for better evaluation of the relative flammability. Fire Mater. 1981 5 39-40. 

Day AG. Oxygen index test Temperature effect and comparison with other flammability tests. Plast. Polym. 1975 43 64-67. 

Relative to carbon/carbon composites, the hybrid composites have a reduced thermal stability in air due to the resin content of the matrix. The flammabilities of the hybrid composites, as measured by the limiting oxygen index (LOI) test (63) are given in Figure 36. Pure carbon/carbon composites are not inflammable in... 

The limiting oxygen index (LOI) measures the minimum oxygen content that is required to sustain a flame [10]. The specimen in this test is in a vertical orientation, but it is the top of the specimen that is ignited. Because the specimen burns in a candle-like fashion, LOI may not be representative of fire situations. However, LOI does give quantitative information and may be useful for ranking the relative flammability of samples. 

Flame retardance is another important property and is defined by different test methods. Some of the small-scale methods include horizontal flame spread (FMVSS 302, ASTM D-1692) vertical flammability (ASTM D-3014, so-called Butler Chimney Test), limiting oxygen index (ASTM D-2863), and smoke density (ASTM D-2840). 

Combustion properties of interest in cellular plastics and elastomers include ease of ignition (ignitibility), support of combustion (oxygen index), relative extent and time of burning, surface flammability, flame read, smoke evolution properties, and rate of beat release. The following test methods are either concerned solely with cellular plastics, m are used for both cellular and solid plastics. 

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