This part of GB/T 2406.2 - 2009 focuses on the room temperature test of plastic oxygen index method. It describes the principle of using oxygen index method to determine the combustion behavior of plastics at room temperature environment. Specifies the technical requirements of required equipment, such as combustion cylinders, gas source adjustment devices, etc. Detailed preparation methods for plastic samples, standardized test procedures, including adjusting the mixing ratio of oxygen and nitrogen, igniting the sample, and observing combustion phenomena to determine the oxygen index of plastics. The standard provides a unified room temperature combustion performance test specification for the plastics industry, helping to evaluate the flame retardant characteristics of products in conventional environments and improve the safety of plastic products.