How do you test for limiting oxygen index?

 

1. Prepare the sample: Prepare the sample from the material to be tested. Usually, the size of the sample is rectangular or strip, and the selection of the size should meet the requirements of relevant standards or test methods.

 

2. Experimental equipment: Use a dedicated LOI test instrument, usually an LOI analyzer. The instrument controls the mixing ratio of oxygen and nitrogen and measures the combustion of the sample.

 

3. Sample treatment: Before testing, the sample usually needs to go through some treatment steps to ensure that its surface is clean and free of impurities. This may include washing, drying and removing any contamination that may affect the test results.

4. Test process: Place the sample in the combustion chamber of the LOI test instrument. The combustion chamber usually consists of a vertical column of quartz glass on which the sample is fixed. Then, by controlling the mixing ratio of oxygen and nitrogen, the oxygen concentration in the combustion chamber is gradually reduced.

 

5. Observation and recording: During the process of reducing the oxygen concentration, observe the combustion of the sample. When the sample is capable of self-sustained combustion, record the oxygen concentration at that time. This oxygen concentration is the limiting oxygen index of the sample.

 

6. Data analysis and reporting: Calculate and record the limiting oxygen index of the sample according to the test results. The test data can also be compared with relevant standards or reference values to assess the combustion characteristics and fire safety of the material.

 

It should be noted that the detection limit oxygen index may involve some specific instruments and test methods, and these may vary according to the equipment and standards used. Therefore, when performing limiting oxygen index testing, relevant international standards (such as ASTM D2863) or guidelines provided by the instrument manufacturer should be referred to to ensure correct testing procedures and reliable results.