The Test Method of Flame Retardant Fabric--LOI Method
2016-04-09 08:13 | writer: admin
The LOI is the materials of oxygen and nitrogen mixture can just keep burning required the lowest oxygen concentration under the stipulate test method, which express in the volume percentage of the oxygen.
Before testing, draw a scale on the test sample 50mm far from the flame and put it on the test nip in vertical. And the distance from the top of the test sample to the incendiary cylinder should more than 10mm, estimate the origin oxygen concentration and adjust and make the oxygen and nitrogen mixture gas flow from down to up and make sure the gas speed is（40±10）mm/s at any time in the incendiary cylinder. Let the air flow in 30s, in order to clean the incendiary cylinder. Then light the top of the test sample by igniter and make sure the top are ignited totally, move the igniter and keep time at the same time. At this moment, don’t change the flow and oxygen concentration.
In testing, when the burning time more than 3min or the front of flame exceed the scale, then should reduce the oxygen concentration and test again. On the contrary, should add the oxygen concentration. When adjust the oxygen concentration value difference of increasing and reducing less than 0.5%, should calculate the OI of the materials according to the reduced oxygen minimal inhibitory concentration and test three times in this range.
High temperature LOI test method is used for testing the LOI of one material in different temperature, which temperature is higher than the indoor temperature.