Oxygen Index (OI)
This test method covers a procedure for measuring the threshold-limit conditions to allow self-sustained burning of non-metallic materials in various oxidant gases under specific conditions of pressure, temperature, flow, and fire propagation. The objective of the test is to determine the minimum concentration of oxygen required for a material to support candle-like burning after being positively ignited in a flowing oxygen/nitrogen mixture.
For this procedure, the test specimen (generally a thin strip) is supported vertically in a mixture of oxygen and nitrogen flowing upward through a glass cylinder. The upper end of the specimen is ignited and the subsequent burning behavior of the specimen is observed. This observation is used to compare the time period for which burning continues, or the length of specimen burned, with specified limits for each. By testing a series of specimens in different oxygen concentrations, the minimum oxygen concentration is determined.
This test can also be performed at pressures above atmospheric in WHA's Promoted Combustion Test System.
Most of our standard testing can be performed in 2-3 weeks and we also offer expedited testing services, if required.