ASTM D2863 Minimum Oxygen Concentration to Support Candle-Like Combustion of Plastics (Oxygen Index)

The ASTM D2863 standard comprises three test procedures A, B, and C, involving top surface ignition, propagating ignition, and the comparison with a specified minimum value of the oxygen index. The measured oxygen concentration can be used for material comparison, development, and quality control. However, the oxygen index result does not directly reflect actual fire performance under use conditions or predict performance in a specific fire environment.

Get Certified ASTM D2863 Testing for Reliable Oxygen Index Evaluation

The combustion behavior of plastic materials can differ based on the plastic’s composition and the environment in which combustion occurs. Thus, oxygen index testing helps assess the comparative combustibility of plastics under defined conditions. The ASTM D2863 standard specifies a method for determining the minimum concentration of oxygen below which candle-like combustion will not sustain. Results can support material development, quality control, and comparisons of plastic formulations.

• Measures the Oxygen Index of plastics.
• Determines the lowest oxygen level that will permit combustion.
• Assesses the burning behavior of the candle.
• Works with mixtures of controlled oxygen and nitrogen gas.
• Tests plastic specimens that are mounted vertically.
• Facilitates the comparison of plastic materials.
• Assists in the assessment of combustion characteristics relative to each other.
• Assists in material creation and quality control.

What are the Uses of ASTM D2863 Testing?

ASTM D2863 testing helps laboratories determine the amount of oxygen needed to keep plastic material burning. Engineers use the results to compare formulations and characterize combustion behavior in controlled laboratory conditions.  The ASTM D2863 standard-

• Determines oxygen index.
• Compares combustion properties.
• Assists in comparing plastic formulations.
• Supports material development.
• Assists in the determination of the alteration of the composition of a material.
• Supports quality control.
• Provides information to research and development.
• Contributes to the description of the combustion behavior of plastics.

Which materials can be tested under ASTM D2863?

ASTM D2863 is applicable to plastic materials that can be fabricated into appropriate vertical test specimens for oxygen index testing. When the specimen requirements are met, the test can assess various plastic formulations and material forms. Before setting up specimens for the test, technicians should determine the plastic type, specimen size, conditioning, and combustion characteristics.

Why is ASTM D2863 Important?

ASTM D2863 is a standardized procedure for measuring the oxygen required to sustain candle-like burning of plastics. Standardized testing compares materials under controlled atmospheric conditions. These results help characterize the material, develop formulations, and support quality control when evaluating the combustion behavior of plastics.

ASTM D2863 Testing Process and Data Collection

Technicians select representative plastic specimens and condition them according to requirements. They then place each specimen in the oxygen index apparatus in the upright position. The operator then sets up a controlled atmosphere of oxygen and nitrogen and introduces the ignition source to the specimen. The operator observes the combustion behavior and adjusts it according to the test procedure. Finally, the minimal oxygen concentration that allows the specified candle-like combustion behavior is calculated by the analysts. Laboratories report the oxygen index and the relevant information on the specimen and the test conditions.

Common Challenges and Troubleshooting

Consistent specimen preparation, gas-flow control, ignition, and observation are essential to obtaining accurate ASTM D2863 results. Changes in specimen condition or gas concentration may affect combustion behavior and the oxygen index. Technicians should check the gas supply and flow-control systems before testing. They should also learn how to prepare specimens consistently and maintain the required test conditions during testing.

• The test results report the oxygen index per ASTM D2863, expressed as oxygen concentration in volume percent.
• Engineers use the oxygen index value to assess the oxygen concentration required to sustain combustion and compare the combustion characteristics of plastic materials.
• Higher oxygen index values indicate that a higher oxygen concentration is required to sustain the specified combustion condition.
• Engineers interpret the results as comparative combustion data and do not use oxygen index values alone to predict actual fire performance.
• Technicians follow consistent specimen preparation and controlled gas conditions to obtain reliable and comparable results.

Link to ASTM D2863