ASTM E84: Flame Spread and Smoke Density Testing

ASTM E84 is crucial for understanding how building materials react to fire. It measures the surface burning characteristics, including flame spread and smoke development indices, to ensure safety in building materials. These measurements are important for comparing various materials and meeting building code requirements.

Buildings need materials that can withstand fire hazards. With tests like ASTM E84, which involves exposing materials to controlled fire conditions, architects, builders, and safety professionals can make informed decisions about the materials they use. This ensures that buildings are both safe and compliant with fire safety regulations.

Understanding ASTM E84 also involves knowing how the test is conducted, the equipment used, and the type of results expected. This can help stakeholders in construction and safety fields to interpret test data accurately and apply it effectively in their projects.

Key Takeaways

  • ASTM E84 measures flame spread and smoke development.
  • Knowing the test procedure helps in understanding results.
  • Compliance with ASTM E84 is crucial for building safety.

ASTM E84 Overview

ASTM E84 is a standardized test method used to measure the surface burning characteristics of building materials. This test is crucial for determining how a material reacts to fire and how much smoke it produces.

Scope of ASTM E84

The scope of ASTM E84 includes assessing the flame spread and smoke development characteristics of materials. This test is essential for materials used in interior wall and ceiling finishes. It measures two main indices: the Flame Spread Index (FSI) and the Smoke Developed Index (SDI).

FSI measures how quickly flames travel across a material’s surface, while SDI measures the amount of smoke emitted during burning. Meeting the specific requirements of these indices ensures materials are safe for use in building interiors. The test can also extend to a 30-minute duration for specific materials, following the standard method.

ASTM E84 Test Method

The ASTM E84 test is conducted in a controlled environment, using a Steiner Tunnel. The test setup involves placing a 24″ wide by 24′ long sample into the tunnel. Two burners, providing 89kW of energy, expose the sample to flames under a removable lid with forced draft conditions.

During the 10-minute test, both FSI and SDI are recorded. This allows for a detailed assessment of the material’s behavior under fire conditions. The test method is crucial in ensuring building materials are compliant with safety standards, evaluating their potential contribution to fire spread and smoke generation.

Test Principles

ASTM E84 assesses materials’ surface burning characteristics, focusing mainly on the flame spread and smoke developed indexes. These parameters help determine a material’s fire safety.

Flame Spread Index

The Flame Spread Index (FSI) measures how fast flames spread across a material’s surface. A sample, typically 24 inches by 24 feet, is placed in a Steiner Tunnel. This tunnel uses two burners producing 89kW of energy to ignite the material.

The burning behavior over a 10-minute test duration is closely monitored. Materials receive an FSI rating by comparing their performance to standard benchmarks, such as asbestos cement and red oak. Low FSI ratings indicate slower flame spread, making materials safer for use in construction.

Manufacturers often need to meet specific FSI thresholds to comply with building codes. For example, materials with an FSI of less than 25 are often required for use in exit corridors.

Smoke Developed Index

The Smoke Developed Index (SDI) gauges the amount of smoke a material produces during combustion. Excessive smoke can obscure visibility and hinder evacuation during a fire, making this a crucial safety measure.

During the same 10-minute Steiner Tunnel test, sensors measure the smoke density produced by the burning material. The SDI is calculated based on the smoke obscuration data collected. Lower SDI values indicate less smoke production, which is desirable for safer building environments.

Materials with low SDI are preferred in areas where smoke could severely impact visibility and evacuations, such as hospitals and schools. Meeting strict SDI criteria ensures that materials not only burn less but also produce less smoke, enhancing overall fire safety.

These indices are necessary benchmarks in the evaluation of building materials, aiding in the creation of safer structures.

Sample Preparation

Proper sample preparation is crucial for accurate results in ASTM E84 testing. This involves conditioning the material and ensuring the right sample dimensions.

Material Conditioning

Materials must be conditioned to stabilize their moisture content before testing. This can be done by storing them at a controlled temperature of 73°F (23°C) and a relative humidity of 50% for at least 48 hours.

Conditioning helps achieve consistent test results. Extreme temperatures or humidity can alter the material’s behavior during the test, potentially leading to inaccurate measurements. Conditioning at standardized conditions ensures the material behaves predictably and comparably.

Materials like textiles, paper, and composite don’t all absorb moisture at the same rate. Therefore, proper time and environmental control are key.

Sample Dimensions

Samples for ASTM E84 testing must meet specific dimensions: 24 inches wide by 24 feet long. These dimensions fit the Steiner Tunnel apparatus, which is used for the test.

It’s important to accurately cut the sample to ensure it fits within the tunnel without any gaps. Gaps or incorrect sizes can lead to air currents or flame spread that don’t reflect real-world conditions. Precision in dimensions helps simulate actual building scenarios where these materials will be used.

Correct dimensions ensure the test reflects true performance.

Test Equipment

ASTM E84 testing involves specialized equipment and precise measurement tools to determine the surface burning characteristics of building materials.

Test Apparatus

The primary equipment used in ASTM E84 testing is the Steiner Tunnel. This tunnel is 24 feet long and accommodates a sample that is 24 inches wide. The sample is placed on the ceiling of the tunnel with a removable lid. Two large methane gas burners provide a controlled flame, generating around 89 kW of energy.

A regulated induced draft system ensures consistent airflow and removes combustion products from the tunnel. This system is essential for maintaining the integrity of the test and achieving accurate results. The tunnel’s conditions simulate the effects of a sustained fire on the material being tested.

Measurement Instruments

ASTM E84 testing employs specific measurement instruments to record critical data. A photometer measures the smoke developed index by tracking light obscuration. Additionally, thermocouples monitor the temperature changes along the length of the tunnel, which helps to evaluate the material’s flame spread index.

These instruments are calibrated regularly to ensure precision. The accuracy of these measurements is crucial for producing reliable data that building codes and safety standards can rely on. The results include both the flame spread index and the smoke developed index, providing a comprehensive assessment of the material’s performance during a fire event.


ASTM E84 outlines specific steps to evaluate the surface burning characteristics of building materials. Below are the detailed instructions on the setup, operating conditions, and observation methods.

Test Setup

The ASTM E84 test requires precise preparation. The test sample, a material typically 24 inches wide and 24 feet long, is placed inside the Steiner Tunnel.

Two burners are positioned within the tunnel, providing 89 kW of energy. The test sample is mounted on the ceiling of the tunnel and covered with a removable lid. A forced draft ensures a controlled airflow throughout the testing process.

All equipment must be calibrated properly. This includes the gas flow meters, pressure gauges, and thermocouples. Ensuring these are operational helps maintain consistency and reliability in test results.

Operating Conditions

During the 10-minute test, the environment inside the tunnel must remain stable. The burners are ignited to create a controlled flame that interacts with the test sample.

The temperature should be monitored continuously. This allows for accurate measurement of heat release and ensures that the sample is subjected to consistent fire exposure.

Maintaining a draft speed of 240 ft/min is crucial. Any deviation could skew the results, impacting the accuracy of the flame spread and smoke development indices. This controlled airflow mimics real-world conditions, providing data that’s reflective of actual building fire scenarios.

Observation and Recording

Throughout the test, observations are made concerning how the flame spreads across the sample. Key parameters like the Flame Spread Index (FSI) and Smoke Developed Index (SDI) are recorded. These indices provide comparative metrics for the test material’s fire resistance.

Detailed notes are taken on the distance flame travels along the specimen. These observations are essential for calculating the Flame Spread Index. Additionally, the density of the smoke produced is measured, contributing to the Smoke Developed Index.

Capturing high-resolution video or photographic documentation can enhance the accuracy of recorded data. This visual evidence supports the numerical data, ensuring a comprehensive assessment of the material’s fire behavior.

Results and Reporting

In ASTM E84 testing, the process includes calculating indices that measure flame spread and smoke development. Interpretation of these results is crucial to understanding the fire performance of building materials. Accurate documentation is essential for compliance and future reference.

Calculating Indices

The ASTM E84 test measures two main indices: Flame Spread Index (FSI) and Smoke Developed Index (SDI). FSI indicates how fast flames move across a material’s surface, while SDI measures the amount of smoke it produces.

During the test, a 24-inch wide by 24-foot long sample is placed in a Steiner Tunnel. Two burners provide 89 kW of energy for 10 minutes. The movement of flames is observed, and the speed is recorded as the FSI. Simultaneously, smoke density is measured to determine the SDI.

These indices help classify materials into different categories, affecting their approval for various construction applications.

Interpreting Results

Interpreting the results involves comparing the FSI and SDI against established benchmarks. For instance, a lower FSI indicates a slower flame spread, which is preferable. Similarly, a lower SDI signifies less smoke production.

Materials are often classified based on their performance:

  • Class A: FSI 0-25, SDI 0-450
  • Class B: FSI 26-75, SDI <450
  • Class C: FSI 76-200, SDI <450

These classifications help decide where materials can be safely used. For example, materials with a Class A rating are suitable for areas requiring high fire resistance.


Documentation of the ASTM E84 test includes detailed test reports that must be carefully maintained. Each report typically contains:

  • Test Date and Location: Including the facility and conditions.
  • Material Description: Type, size, and any specific treatments applied.
  • Test Protocol: Detailed steps followed during testing.
  • Results: FSI and SDI values along with any observations.

Proper documentation is crucial for regulatory compliance and serves as a reference in case of audits or reviews. Companies can store these reports in both digital and physical formats for future reference. Maintaining organized records helps in rapid access and validation during inspections.

For more detailed information, visit Intertek’s ASTM E84 standard page.

Limitations and Considerations

There are several important aspects when it comes to understanding the ASTM E84 test. It is crucial to look at how materials behave during the test and recognize the limitations that come with this standard.

Material Behavior

The ASTM E84 test measures how materials react in a fire by assessing flame spread and smoke production. This test is done in a controlled environment, usually a 25-foot long tunnel, using specific test conditions. During the test, a sample is exposed to a flame at one end, and the spread of fire is monitored.

Certain materials may perform differently in real-world situations than they do in the test tunnel. For example, materials that do well in the test might not perform as expected in an actual fire where conditions can vary significantly. It is important to consider how the material will behave in different environments and situations beyond the test conditions.

Test Limitations

While the ASTM E84 standard provides useful data, it has some limitations. The test focuses only on surface burning characteristics and does not account for factors such as the structural integrity of materials during a fire. This means that other important fire performance metrics are not assessed.

Another consideration is that the test is typically performed over a short duration of 10 minutes. This limited time frame may not provide a complete picture of how materials will perform during a prolonged fire. Users must understand that passing the ASTM E84 test does not guarantee complete fire safety and should consider additional testing or safety measures.

Compliance and Applications

ASTM E84 involves ensuring materials meet specific fire safety standards. This section covers how building codes and various industries apply these standards.

Building Code Requirements

ASTM E84 is crucial in meeting building code fire safety requirements. It defines how materials should behave in a fire, focusing on flame spread and smoke development.

Building materials must achieve certain flame spread and smoke density ratings, usually based on how they perform in the ASTM E84 test. For example, a Class A rating indicates the lowest flame spread. This is often required for walls and ceilings in commercial buildings.

The test typically involves placing a 24-inch by 24-foot sample in a tunnel and exposing it to burners, simulating a real fire scenario. Materials must pass this test to be approved for use. Building inspectors and safety regulators rely heavily on these results to certify that construction projects comply with local fire codes.

Industry Applications

Various industries apply ASTM E84 standards to ensure fire safety. Construction is a primary user, requiring materials like insulation, drywall, and flooring to meet E84 ratings.

The HVAC industry uses ASTM E84 to test ducts and tapes for their fire resistance. During the test, materials are exposed to high energy from burners, making sure they can withstand and limit the spread of fire. Manufacturers often use the results to label their products with the appropriate fire ratings, guiding builders and contractors in selecting compliant materials.

Fire retardant coatings, for example, are tested under ASTM E84 to determine their effectiveness in slowing flame spread. This helps in selecting the right coatings for buildings, ensuring higher safety standards in various environments.

Frequently Asked Questions

This section covers specific aspects of the ASTM E84 standard, including fire ratings, measurement procedures, and relevant classifications.

What are the requirements to achieve a Class 1 or Class A fire rating according to ASTM E84?

To achieve a Class 1 or Class A fire rating under ASTM E84, a material must have a Flame Spread Index (FSI) of 25 or less. This level of flame spread is considered minimal and indicates the material’s high resistance to fire.

How does ASTM E84 measure smoke developed index, and what does the index indicate?

ASTM E84 measures the Smoke Developed Index (SDI) by recording the amount of smoke a sample emits while burning. The SDI indicates the visibility through the smoke; lower values suggest less smoke and better visibility during a fire.

What sample size is specified by the ASTM E84 standard for testing materials?

The ASTM E84 standard specifies a sample size of 24 inches wide and 24 feet long. This size allows for consistent testing conditions and reliable results in the Steiner Tunnel test setup, which evaluates the material’s fire behavior.

Could you explain the fire rating classifications within ASTM E84?

ASTM E84 classifies materials into three classes based on the Flame Spread Index (FSI). Class A (or Class 1) has an FSI of 0-25, Class B (or Class 2) has an FSI of 26-75, and Class C (or Class 3) has an FSI of 76-200. These classifications help determine the fire safety of building materials.

Is there an international equivalent to the ASTM E84 standard, and if so, what is it?

Yes, there is an international equivalent to the ASTM E84 standard. The ISO 9705 standard is widely recognized for testing the reaction to fire of materials in a full-scale room configuration, providing similar fire safety assessments.

In the context of ASTM E84, what differentiates a Class B fire rating from Class A and Class 1 ratings?

A Class B fire rating, or Class 2, according to ASTM E84, has a Flame Spread Index (FSI) ranging from 26 to 75. Class A (or Class 1) ratings have an FSI of 0 to 25, indicating higher fire resistance. Class C (or Class 3) ratings have an FSI of 76 to 200, showing a lower fire resistance than Class B.

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