Have you ever wondered how protective flame resistant (FR) fabrics resist catching fire? We have your answers.
When a flame, spark or intense heat reaches a flammable substance, a chemical reaction occurs that produces heat and light. This reaction, termed “combustion,” is the basis of fire. Have you ever wondered how protective flame resistant (FR) fabrics resist catching fire?
Arc flash, flash fire and combustible dust hazards are commonplace in many industrial settings, including the oil and gas and electric industries. Daily wear FR personal protective equipment (PPE) helps provide a final safeguard to those who may experience these short-term thermal hazards. Yet, to provide this critical protection, PPE must harness the science behind fire and FR fabrics.
To develop effective FR fabrics, textile manufacturers must first have a deep understanding of the science of fire. Manufacturers have developed different technologies to create FR textiles, each with their own merits. To help you understand how these approaches work to snuff out a flame, we explain the various technologies, explore their advantages and drawbacks, and provide some insight into how they work to provide flame resistance.
What is Fire?
We generally think of fire as requiring three separate components: oxygen, heat and fuel. Heat is required to break down the fuel in gaseous components, and then oxygen reacts with the gas that is formed. The heat produced then breaks down more fuel into gases, and this cycle continues until one of the three components—oxygen, heat or fuel—is removed or consumed.
However, the chemical reaction that results in combustion is actually very complex and requires another component that we cannot observe. In order to react with oxygen, the fuel must break apart into highly reactive molecules called “radicals”. These radicals react with oxygen and form more radicals in a chain reaction that results in fire. Therefore, scientifically, fire requires four components: fuel, oxygen, heat and this chain reaction.
The Science of Flame Resistance
By using a deep scientific understanding of fire, fabric manufacturers have developed strategies for flame resistance that are focused on removing one of the components required to sustain the fire. All of these technologies are designed to snuff out a flame and mitigate the risk of injury for the wearer, but each of them has their own set of advantages. Since each of the technologies can be made permanent for the life of the protective garment and will not wash out with laundering, the selection of the technology will depend on the specific hazard and the preference for other attributes.
This article originally appeared in the April 2020 issue of Occupational Health & Safety.
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