Flammable Vs Combustible | 10 Key Differences

Understanding the differences between flammable and combustible substances is crucial, especially when managing risk in environments with these materials. In our comprehensive guide, we dive into the world of hazardous materials and explore these two categories in depth. From defining the basics to unpacking the nuances that separate flammable from combustible materials, this blog post is designed to provide an in-depth understanding. We will also shed light on the regulations governing their use, explain safety precautions, and highlight important aspects of storage and handling.

Whether you work directly with these materials or are just interested in expanding your knowledge, this blog will serve as a useful resource to enhance safety, promote understanding, and inform effective practices. So, let’s delve into the distinct world of flammable and combustible substances and learn about the 10 key differences that set them apart.

What is Flammable?

Flammable refers to a substance or material that can ignite or catch fire easily at a specific range of temperatures. This property is determined by the flash point of the material. The flash point is the lowest temperature at which the vapors of a volatile material can ignite when an ignition source like a flame or spark is present.

Flammable materials are characterized by a flash point below 37.8°C (100°F). These materials are a greater fire hazard because they can ignite at room temperature or temperatures commonly encountered. Examples of flammable substances include gasoline, alcohol, and many organic solvents.

It’s crucial to remember that it’s not the liquid that burns but the vapors it gives off. These vapors can ignite and cause a fire or explosion when mixed with air in the right proportions and exposed to an ignition source. For this reason, handling and storage of flammable materials require specific safety measures to minimize the risk of a fire or explosion.

What's the Difference Between Flammable and Combustible

What is Combustible?

The term “combustible” refers to a substance or material that can catch fire and burn. The key factor distinguishing combustible materials from flammable ones is the temperature at which they ignite, known as the flash point.

Combustible liquids typically need to reach higher temperatures than flammable liquids to catch fire. In essence, the flash point of a combustible liquid is higher than that of a flammable liquid. This higher flash point means combustible liquids generally pose less immediate fire risk under normal working conditions than flammable liquids. However, they can still pose significant fire hazards under the right circumstances.

Knowing the flash point and other combustion properties of any potentially combustible materials you work with is essential. This understanding enables you to take appropriate precautions in handling, storing, and disposing of these substances to maintain a safe environment.

The Difference Between Flammable and Combustible

Key Differences Between Flammable and Combustible

While both flammable and combustible substances have the potential to catch fire, the key differences between them lie in the specific temperatures or flash points at which they ignite. Here are the main differences:

AspectFlammable SubstancesCombustible Substances
DefinitionMaterials that easily catch fire and ignite at or below their flash point.Materials that burn at higher temperatures and require higher ignition sources.
Flash PointLow flash point (e.g., gasoline)Higher flash point (e.g., wood)
Ignition TemperatureLow ignition temperatureHigher ignition temperature
Flammability RangeWide flammability rangeNarrow flammability range
StateCan be in gas, liquid, or solid form.Typically found as solids.
VolatilityHigh volatilityLower volatility
ExamplesGasoline, alcohol, propaneWood, paper, cloth, cardboard
Fire RiskHigh fire riskLower fire risk
Fire SuppressionMay require specialized extinguishing agents due to higher volatility.Traditional fire extinguishers often effective.
Regulatory StandardsGoverned by specific regulations and safety guidelines.Subject to safety regulations as well.
Environmental ImpactAccidental spills can lead to rapid fires and environmental hazards.Slower burning, may have less immediate environmental impact.
Special ConsiderationsSpecial precautions needed for storage, transportation, and handling.Still require safety measures but not as stringent.

1. Flash Point

This is the lowest temperature at which a substance will ignite. Flammable substances have a lower flash point than combustible substances, which ignite at lower temperatures and present a higher risk in normal working conditions. In general, a substance is considered flammable if its flash point is less than 100°F (37.8°C), while a substance is considered combustible if its flash point is between 100°F and 200°F (37.8°C and 93.3°C).

2. Ignition Temperature

Combustible materials typically require higher temperatures to ignite than flammable ones. This means combustible materials may not ignite in the same conditions that would cause flammable materials to catch fire.

3. Risk Level

Because flammable substances ignite at lower temperatures, they tend to pose a greater fire risk under normal conditions than combustible substances. However, both types can pose significant fire hazards under the right circumstances.

4. Rate of Combustion

Flammable substances typically burn faster and more violently than combustible substances due to their lower flash point and ignition temperatures. However, both can cause damaging fires if not properly controlled.

Remember, it’s important to handle and store both flammable and combustible substances properly to prevent fires. This includes keeping them away from ignition sources and following safety guidelines regarding their use and storage.

Difference Between Combustible and Flammable

Other Differences Between Flammable and Combustible

In addition to the previously mentioned differences, the following are additional distinctions between flammable and combustible substances:

  • Labeling and Classification: Regulatory bodies like the U.S. Occupational Safety and Health Administration (OSHA) and the National Fire Protection Association (NFPA) classify and label flammable and combustible liquids differently. Labeling is important for safety measures and handling procedures.
  • Storage Requirements: The storage of flammable liquids generally requires more stringent safety measures due to their lower flash points. For example, flammable liquids are typically stored in specially designed, fire-resistant safety cabinets. Combustible liquids, while still requiring safe storage, usually have slightly less stringent storage requirements.
  • Transportation: Flammable substances often have more restrictions when it comes to transport due to their high reactivity. They usually require special containers and safety precautions during transport, while combustible substances might not need the same level of precaution.
  • Vapor Pressure: Flammable liquids typically have a higher vapor pressure than combustible ones, meaning they can produce more flammable vapors at lower temperatures. This is why flammable liquids often pose a greater risk of fire or explosion.
  • Handling and Use: Because of their higher volatility, flammable substances require stricter handling procedures. Workers handling these substances must use special equipment and protective clothing to prevent accidents. In contrast, handling combustible substances might not require the same degree of protection, although safety should always be a priority.
  • Spill Control: Flammable substances can pose an immediate fire risk if spilled, particularly in a confined space or near an ignition source. Consequently, quick and effective spill control measures are critical. While it’s important to control spills of combustible substances too, the immediate fire risk is generally lower.
  • Disposal: Flammable substances often require special disposal methods to prevent fire or explosion risks. Combustible substances must also be disposed of safely, but the requirements may be less stringent.

It is essential to remember that both flammable and combustible substances can be hazardous and require careful handling, storage, and disposal. Always refer to Material Safety Data Sheets (MSDS) or Safety Data Sheets (SDS) for specific safety information about each substance.

Difference Between Flammable and Combustible

Where To Store Flammables And Combustibles

The storage of flammable and combustible liquids is a crucial part of maintaining a safe working environment. Following the recommended guidelines is important to reduce the risk of fires and explosions.

General Guidelines


  • Designated Areas: Flammable and combustible materials should be stored in specially designated areas or storage cabinets to resist fire and contain leaks and spills.
  • Temperature Control: Keep the storage area cool and dry. The area should be well-ventilated to prevent the build-up of vapors, and it should not be exposed to open flames, sparks, or any ignition sources.
  • Accessibility: The storage area should be easily accessible to quickly respond to emergencies and restrict unauthorized access.
  • Proper Labeling: All storage areas and containers should be clearly labeled, indicating their hazard. This helps in immediate recognition of the potential hazards in case of an emergency.
  • Quantity Limitations: Avoid excessive storage of flammable and combustible liquids. Only keep quantities necessary for the operation at hand. This minimizes the potential fuel for a fire and the risk of spills.

Specific Guidelines


  • Safety Containers: Flammable and combustible liquids should be stored in safety containers that meet the specifications of organizations like OSHA or NFPA. Safety cans are usually made of metal and are equipped with flame arresters and pressure relief mechanisms.
  • Safety Cabinets: If flammable and combustible liquids exceed 10 gallons (38 liters) in a building, they should be stored in flammable liquid storage safety cabinets. These cabinets are designed to protect the contents from fire for up to 10 minutes, giving people enough time to evacuate and the fire department time to respond.
  • Storage Rooms: If the quantity of flammable and combustible liquids exceeds the maximum allowable limit in safety cabinets, they should be stored in specially designed storage rooms. These rooms should be constructed to withstand fire for up to 2 hours.
  • Storage Tanks: Storage tanks might be necessary for extremely large quantities of flammable and combustible liquids. Aboveground tanks should be avoided if possible, but they should be located safely from buildings and property lines.

These guidelines are meant to minimize the risk of storing flammable and combustible materials. Always consult the latest regulations and guidelines from your local fire department and OSHA for the most accurate and up-to-date safety practices.

Flammable and Combustible

Safety Training and Education For Flammable and Combustible

Safety training and education are crucial in reducing the risk of handling flammable and combustible materials. Such training helps employees understand the risks, preventative measures, and proper response in case of an incident. Here are some key components that should be included in safety training and education for handling flammable and combustible materials:

  • Understanding Material Properties: Educate employees about the properties of the flammable and combustible materials they work with. This should include understanding Material Safety Data Sheets (MSDS) and recognizing hazard symbols and labels.
  • Handling and Storage: Employees should be trained on properly handling and storing flammable and combustible materials. This includes understanding the importance of using the right tools and equipment, ensuring proper ventilation, and adhering to storage guidelines.
  • Emergency Procedures: Training should cover what to do during a spill, fire, or other emergency. This includes knowing how to use fire-fighting equipment, understanding evacuation procedures, and learning how to respond to different types of fires (for example, using a water extinguisher on a flammable liquid fire can be dangerous).
  • Disposal of Flammable and Combustible Waste: Employees should be trained on the correct disposal methods of waste containing flammable or combustible materials, including using proper waste containers and disposal facilities.
  • Personal Protective Equipment (PPE): Training should also involve knowing which types of personal protective equipment to use when handling these materials, how to properly use and maintain this equipment, and understanding its limitations.
  • Regular drills: Regular drills can ensure employees know how to react in an emergency. These drills include evacuation procedures, fire extinguishers, and spill containment handling.
  • Ongoing Training: Safety training should be ongoing to account for changes in regulations, the introduction of new materials or processes, and to reinforce safety principles. Refresher courses should be held regularly to ensure that the information remains fresh in employees’ minds.

In conclusion, safety training and education are essential to a comprehensive safety program when working with flammable and combustible materials. The goal of the training should be to instill a safety culture where all employees understand the risks associated with their work and know how to take the necessary precautions.

Conclusion

In conclusion, understanding the distinction between flammable and combustible materials is paramount for maintaining safety in any environment where these substances are used. While often used interchangeably in the common language, the terms flammable and combustible refer to different categories of hazardous materials regarding safety and fire regulations.

Their key difference lies in their flash points or the lowest temperature at which they can ignite. Flammable materials ignite at lower temperatures and pose a higher risk than combustible ones. Furthermore, how these materials are stored, handled, and disposed of can significantly impact safety and potentially mitigate the risk of a fire or explosion.

As we explored the ten key differences between flammable and combustible substances, we learned that these differences have profound implications for safety protocols and procedures. Thus, this knowledge is theoretical and has practical applications in various fields, from construction and manufacturing to transportation and storage.

By keeping these differences in mind and adhering to the guidelines set forth by safety and health administrations, we can effectively manage the risks associated with flammable and combustible materials. Ultimately, the primary goal is to ensure the safety of all individuals who work with or around these substances.

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Author

Muhammad Raza

Muhammad Raza is an experienced safety professional and trainer, dedicated to improving occupational health and safety practices in Saudi Arabia. His expertise extends to educating others, thus cultivating a comprehensive culture of safety within the workplace.