ASTM D2843 Standard Test Method for Density of Smoke from the Burning or Decomposition of Plastics

Get Certified ASTM D2843 Smoke Density Testing

The ASTM D2843 test enables laboratories to determine the relative smoke obscuration generated from plastic materials under controlled burning or decomposing conditions. The technician inserts the specimen into a test chamber, subjects it to flame, and the smoke formed during the test extinguishes light transmittance across the chamber. This results in an optical response that can be used to calculate a smoke density rating.

• Plastic Materials: Laboratories evaluate the smoke-producing characteristics of plastics.
• Smoke Obscuration: The method measures the reduction in light transmission caused by collected smoke.
• Controlled Combustion: The test evaluates smoke produced under specified burning conditions.
• Decomposition: The method also considers smoke produced when plastics decompose under the prescribed test conditions.
• Optical Measurement: The apparatus measures smoke’s effect on light transmission.
• Comparative Evaluation: Engineers compare the relative smoke obscuration characteristics of different plastic materials.

What are the uses of ASTM D2843 testing?

ASTM D2843 testing provides information about the relative smoke obscuration characteristics of plastics under controlled combustion or decomposition conditions. Manufacturers, engineers, and laboratories can use the results to compare materials and evaluate differences in smoke production under the specified test conditions. ASTM D2843 test:

• Determines the relative smoke obscuration produced by plastics.
• Evaluates smoke-producing characteristics under controlled conditions.
• Supports comparison of different plastic materials.
• Helps assess how material characteristics affect smoke production.
• Provides optical measurements based on loss of light transmission.
• Supports material research and development.
• Provides information for fire-response material evaluation.
• Helps engineers compare smoke density results between applicable specimens.

Which materials can be tested according to ASTM D2843?

ASTM D2843 applies to plastic materials that can be tested under the specified burning or decomposition conditions. The test is not intended to simulate all scenarios that may be faced in a fire; it measures the smoke obscuration of plastics under controlled laboratory conditions.

• Plastic Materials: Evaluates applicable plastics for smoke-producing characteristics.
• Solid Plastic Specimens: Tests prepared plastic specimens under controlled flame exposure.
• Combustible Plastics: Evaluates smoke produced when applicable plastics burn.
• Decomposing Plastics: Measures smoke obscuration associated with decomposition under the prescribed conditions.
• Different Plastic Materials: Allows laboratories to compare relative smoke-producing characteristics.

Why is ASTM D2843 Testing Important?

Measuring smoke obscuration is important for assessing the fire response of plastic materials because smoke obscuration limits visibility. ASTM D2843 specifies a controlled measurement of the loss of light transmission due to smoke build-up in the test chamber. The results enable engineers to compare the relative characteristics of the production of smoke of plastics under the specified conditions. The test should not be used as a full evaluation of the fire hazard and/or fire risk under fire conditions. Factors affecting the production of smoke include the amount and type of material consumed, humidity, draft, temperature, and oxygen content.

• Smoke Test Chamber: Provides a controlled space where the specimen burns and smoke accumulates.
• Propane Burner: Provides the flame used to expose the specimen under the specified conditions.
• Light Source: Produces the light beam used for optical measurement.
• Photoelectric Cell: Detects the amount of light transmitted through the smoke.
• Meter: Records the optical response associated with light transmission through the smoke.
• Specimen Support: Holds the prepared plastic specimen in the required position during testing.
• Ventilation and Exhaust System: Helps manage combustion products and protect laboratory personnel.
• The test apparatus includes a light source, photoelectric cell, and meter to measure light absorption across the chamber. A representative procedure uses a 25 by 25 by 6 mm specimen in a controlled test chamber with a propane burner.

How is smoke density determined in ASTM D2843?

ASTM D2843 determines smoke obscuration by measuring the reduction in light transmission through smoke collected in the test chamber. Smoke produced as the specimen burns or decomposes travels through the light path and reduces the light reaching the photoelectric cell. The instrument response is then used to calculate the smoke density rating for the conditions of the test.

ASTM D2843 Equipment and Sample Preparation Guide

To get reliable results, technicians must have a controlled smoke test chamber, an appropriate flame source, an optical measurement system, and prepared plastic specimens. Prepare the specimen based on the dimensions defined by applicable regulations, and handle it carefully to avoid surface damage or contamination that could affect the test.

ASTM D2843 Testing Process and Data Collection

First, technicians identify the plastic material and prepare the required specimens. They place the specimen on the supporting screen of the test chamber and set up the burner and measurement system for optical measurement of the specimen under the particular test conditions. The specimen is put in front of the flame, and smoke builds up in the chamber. The smoke diminishes the amount of light that passes through the chamber, and the photoelectric system senses the optical change. Technicians document the instrument response and include specimen identification, test conditions, and observations. The laboratory then performs optical tests and analyzes the results to assign the smoke density rating and to compare the smoke obscuration properties of the plastics being tested.

Common Challenges and Troubleshooting

ASTM D2843 results may be affected by the size of the specimen, specimen preparation, burner conditions, chamber conditions, optical system performance, and temperature, ventilation, and oxygen supply. ASTM states that the amount and type of material, humidity, draft, temperature, and oxygen supply can contribute to smoke obscuration. Consistent specimens should be prepared, and the burner and optical measurement system checked prior to testing. They should also keep the experimental conditions normal to the specified conditions and not contaminate or damage the specimen. If results vary widely from specimen to specimen, the laboratory should consider specimen preparation, specimen size, flame conditions, chamber conditions, optical measurement, and other applicable test parameters. Laboratories should also be equipped with the necessary precautions and safeguards against possible inhalation of combustion products containing hazardous gases or vapors.

• ASTM D2843 produces a smoke density rating based on the loss of light transmission through the smoke collected in the test chamber rather than a general material-performance rating.
• Analysts report smoke density as a dimensionless value, with light transmission expressed as %, test time in seconds (s), specimen dimensions in mm, and temperature in °C. 
• Laboratories report the applicable smoke density result together with relevant specimen information, test conditions, and optical measurement data. The result is intended to compare smoke obscuration characteristics under the specified test conditions.
• Laboratories can achieve repeatable, comparable smoke density results by ensuring the following: samples are prepared the same way, appropriate equipment is used, flame exposure is controlled, optical measurements are accurate, and test conditions are controlled.

Link to ASTM D2843