Determination of Oxidation Induction Time (OIT)
(TS EN ISO 11357-6)

OIT is the relative measure of oxidative degradation of stabilized materials. This is determined by a calorimetric measurement of the time required for the material to reach the beginning of exothermic oxidation at a specified temperature, in oxygen or air, and at atmospheric pressure. The measurement of the oxidation induction period helps to evaluate the plastic of the specific formulation. However, it is not intended to determine the antioxidant concentration. OIT of polyethylene materials is generally carried out under pure oxygen at 200 °C. The minimum oxidation induction time for PE pipes is 20 minutes. The OIT test is a measure of how well PE pipes and fittings are stabilized in manufacturing, welding and long-term strength conditions. If the material does not stabilize well, extrusion, welding or high temperature applications will start to deteriorate, which will reduce pipe life.