Oxygen index test

In other halogen-containing systems, such as flexible PVC and polyolefins, it is preferable to use the zinc borate in conjunction with antimony oxide for maximum performance. In flexible PVC, for example, the zinc borate alone is not very effective in the Oxygen Index test (Fig. 6), but a combination of the zinc borate and antimony oxide (1 1 ratio) outperforms equal weight of antimony oxide at a total loading of more than 10 phr (4). In the presence of alumina trihydrate (ATH), the beneficial effect of using a combination of the zinc borate and antimony oxide is dramatically increased (Fig. 7). 

Fig. 3. Oxygen Index Test of Polylite 33-442 Containing Dibromoneopentyl Glycol, ZB - Zinc Borate, Sb - Antimony Oxide. (Reproduced with permission from Ref. 2. Copyright Plastics Compounding 1985).

Wharton RK. Correlation between the critical oxygen index test and other fire tests. Fire Mater. 1981 5 93-102. 

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

Arcand, Jr CG. The bottom ignition oxygen index test. Text. Res. J. 1972 42 328-330. 

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. 

Wharton RK. Identification of two pass regimes for nylon-66 based rods in the critical oxygen index test. J. Appl. Polym. Sci. 1982 27 3193-3197. 

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

FIGURE 25.4 Superficial char layer of EG-filled PU foam after oxygen index test. (From Modesti, M. and Lorenzetti, A., Eur. Polym. J. 2, 263, 2003. With permission.)... 

ISO 4589 [14, 15], the oxygen index test, gives good repeatability and is useful for quality control purposes. It does not purport to predict performance of a material in real fire conditions and indeed must not be used for this purpose, nor docs it necessarily indicate relative merits of, say, flame-retardant additives in a polymer under conditions other than those specified in the test method see Fig. 4. 

Figure 4 Schematic diagram of oxygen index test (ISO 4589).

The Oxygen Index Test results are not totended to reflect performance of these or any ottier matehats under actual fire condllions. Each user should determine independently whether potentiai fire hazards are associated with the finished product, and whether DOP is suitabla tor the particular use. 

---