The advanced LOI Limiting Oxygen Index Tester accurately determines the relative flammability of plastics and other materials. It conforms to ASTM D2863 and ISO 4589-1, ISO 4589-2 standards and provides a means for safely determining the relative flammability of materials by measuring the minimum oxygen concentration that will support combustion. The test specimens are burned in a precisely controlled atmosphere of nitrogen and oxygen. The operator adjusts the supply gases and uses the flowmeter readings to calculate the oxygen index.