Burned length

NOTE Delay time may be adjusted by varying the burning length of the cigarette. Burning rate in still air is approximately 7 minutes per inch... 

Materials used in floor coverings and textiles, seat cushions, trays and galleys, and electrical and ducting equipment must meet the 12-second test [14CFR 25.853(a) Appendix F Part I (a) (I) (ii)]. In order to pass this test, the average burn length of the materials may not exceed 8 in. the average flame time after removal from the flame source may not exceed 15 seconds. 

Figure 3.37. Burned length of PVC sample vs. ATH content. [Data from Mansour, S. H. Iskander, B. A. Nasrat, L. S., Polym.-Plastics TechnoL Eng., 45, 7, 857-863, 2006.]...

Figure 3.37 shows that addition of aluminum hydroxide decreases the length of a burned sample. The relationship between ATH concentration and burned length is almost linear, as is the relationship between time of burning and amount of ATH. Addition of a small amount of ZnO (1 phr) reduces initial decomposition temperature and it makes it a very effective syneigistic additive to ATH. ... 

Note PEI/PES foam has also passed the following fire performance specifications Aircraft Burn length FAR 25 852/ATS 1000 Smoke density FAR 25 853(a)... 

Method BH of lEC Publication 707-1981 is essentially identical to the test method of ISO 181-1981 and of the withdrawn DIN 53 459-1981. Categories 1,2, and 3 are mainly the same in the latter standard, but Categories 2 and 3 are divided into three sub-groups each, on the basis of burning length and flame spread rate (as detailed in Section 3.1.5.2 and Table 3.11). 

Note Delay time may be adjusted by varying the burning length of the cigarette. Burning rate in still air is approximately 7 minutes per inch (2.5 cm). Since this rate varies with environment and brand of cigarette, it should be tested in each case if accurate delay time is desired. 

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