A material that is non-explosible does not necessarily mean that it is non-combustible. A material can burn vigorously to pose a hazardous situation to any processing plant. The Burn rate/fire train test is used to determine the burning or combustibility characteristics of a substance and to classify the substance into the appropriate packing group. Burn rate testing is used to measure the rate at which a substance, typically a solid propellant or combustible material, burns or undergoes combustion under controlled conditions. This testing process is crucial in various industries, particularly in aerospace, pyrotechnics, and ammunition manufacturing, where the performance and safety of materials are paramount.
Testing Principle and Methodology
The standard recommendation is to test the material in its commercial form, that is as received. In case of uncertainty on how to perform the testing please contact Prime Process Safety Center for guidance. Typically, 100g of the material is used for the purpose of the testing. The sample to be tested is used to form an unbroken strip or powder train and an attempt is made to ignite the material. When ignition is observed during the screening stage, the full burn rate test is conducted. The material to be tested in its commercial form is formed into an unbroken strip or powder train of about 250 mm long by 20 mm wide by 10 mm high in a cool, impervious, low heat nonporous base plate. A hot flame of minimum temperature 1000ᣞC is applied to one end of the train until the material ignites or for a maximum of 2 minutes for regular organic dusts and 5 minutes for metals or metal alloys during the initial screening test.
Applicable Standards
The test is conducted according to the UN/DOT, section 33 ‘’Classification Procedures, Test Methods and Criteria relating to class 4’’ and VDI 2263.
Data Interpretation
If the material does not ignite or smolder and propagates the flame to the 200 mm mark within the test period of 2 minutes or 5 minutes, the material will not be classified as Division 4.1. If the material ignites or smolders and propagates the flame to the 200 mm mark within the test period of 2 minutes or 5 minutes, the material will be classified as Division 4.1 and be subject to the full burn rate test to classify the material into the appropriate packing group. The result of the test is used in classifying the packing group of materials during transportation. Knowing the burning or combustibility characteristics of materials also helps to mitigate flash fire hazards arising from introduction of hot embers and heat generated from friction. The burn rate test for combustible materials also holds significant importance in various industries, particularly in aerospace, pyrotechnics, manufacturing, and other fields dealing with propellants, explosives, and energetic materials. Based on the reaction type, the material will also be classified into the appropriate combustibility class as indicated in the chart below
When to perform the Burn rate/Fire train Test
As stated earlier, a non-explosible material is not necessarily non-combustible. If a material is determined to be No-Go (non-explosible), it is recommended to perform the burn rate test to determine the combustibility characteristics of the material. In summary, burn rate testing of combustible materials should be conducted at various stages, including development, production, modifications, and routine checks, to ensure safety, performance, and compliance with regulations in industries dealing with propellants, explosives, and related materials.
Why work with Prime Process Safety Center
- Prime Process Safety Center is a leader in process safety testing with very experienced laboratory personnel. At Prime Process Safety Center our ultimate goal is to provide accurate, reliable and defensible data that meets industry and regulatory standards. We understand the need for the quality of your data, and we work assiduously to achieve just that.
- We are knowledgeable and experienced in performing dust combustibility screen (Burn rate/Fire train Test) tests, ensuring accurate and reliable results.
- We have state-of-the-art explosibility testing equipment, providing precise and sensitive measurements.
- We follow strict testing protocols and quality control measures to ensure consistent and reliable test results.
- Our team can interpret and analyze the data obtained from the tests, providing valuable insights and recommendations for your specific application or research.
FAQs
What is the burn rate in the context of combustible materials?
Burn rate refers to the speed at which a substance, typically a solid propellant or explosive material, burns or undergoes combustion under controlled conditions. It is a critical parameter that defines the rate of energy release during combustion.
Why is burn rate testing important for combustible materials?
Burn rate testing is crucial as it provides essential data regarding how fast a material burns or combusts. This information is vital for assessing performance, safety, and reliability in applications such as rocket propulsion, ammunition, pyrotechnics, and other industries dealing with energetic materials.
How is burn rate testing performed for combustible materials?
Burn rate testing involves subjecting a sample of the material to controlled conditions, typically within a test chamber, where its combustion is observed and measured. The test measures the rate at which the material burns or undergoes combustion under specific parameters.
What factors influence the burn rate of combustible materials?
Several factors can influence the burn rate of combustible materials, including the composition of the material, particle size, shape, density, pressure, temperature, and the presence of additives or stabilizers.
How is burn rate data utilized in practical applications?
Burn rate data obtained from testing is crucial for designing and developing propellants, explosives, and energetic materials. This data assists in optimizing formulations, predicting performance under various conditions, ensuring safety, and meeting regulatory compliance.