How Do Flame Resistant Fabrics Protect Wearers?

How Do Flame Resistant Fabrics Protect Workers?

Flame resistant (FR) fabrics used in industrial safety applications are materials designed to self-extinguish and prevent the spread of flames, protecting workers from the hazards of heat and flame. Different types of FR fabrics can use several mechanisms to provide protection against the various risks present in industrial environments. Mechanisms of protection include fabric construction, such as the weave or twill of a fabric, garment construction, such as garments that include layers of different materials, and fiber blends in fabrics, such as the use of fibers that are inherently flame resistant.

Why Should You Know the How?

For workers who face flame and electrical hazards, wearing flame resistant protection is par for the course. Though the “what” may be familiar—you must wear protective workwear to protect against flame and electrical hazards—it’s just as important to know the “how” behind that protection. Here’s the “why”: a lack of knowledge of the mechanisms that keep you safe can lead to false assumptions about the protective powers of your garments, leading to less-than-ideal responses in the event of an emergency. Let’s dive into how various FR fabrics protect against the hazards workers face, so you have all the information you need to use your protective garments appropriately.

Arc Flash Protection

What Is An Arc Flash?

An arc flash is a dangerous electrical explosion resulting from a sudden energy discharge. It occurs when an electric arc forms between two conductors, often due to a short circuit or equipment failure. This rapid discharge generates extreme heat, vaporizes nearby metals, and creates a plasma fireball with temperatures reaching up to 34,000°F (four times the surface temperature of the sun). The force of the explosion is so intense that it can create a pressure wave capable of throwing workers off their feet, as well as projecting molten metal and hot gases into the surrounding area.

An arc flash present numerous life-threatening hazards to workers who work on or around electrical equipment:

• Fatal Burns: Due to the intense heat generated, workers near the arc flash are at high risk of fatal burns, even from a distance of up to 3 meters. The temperature can reach 34,000°F in seconds.
  
  
• Convective Heat: The high temperatures within the electric arc cause severe burns. In many cases, clothing ignites, compounding burn injuries.
  
  
• Molten Metal Projections: When an arc flash occurs, metal components can liquefy and be projected at high velocities, potentially causing additional injuries. These metallic fragments are launched with great force due to the pressure from the explosion, posing a risk of serious harm.
  
  
• Shock Waves: The explosion generates a shock wave that can lead to concussive injuries or bodily harm if workers are thrown by the force.
  
  
• Radiation: The arc flash emits both ultraviolet (UV) and infrared (IR) radiation, which can cause further skin damage or even vision impairment.

How FR Fabrics Protect Against Arc Flash Hazards

FR garments are a worker’s last line of defense in the event of an arc flash. Arc flash is a hazard anywhere electrical equipment is present, but utilities workers tend to be the most exposed to this risk. Here’s how their FR garments protect against arc flash hazards:

• Char: In an arc flash event, a worker is facing a tremendous amount of energy going through them in a short time. When the flash comes into contact with FR fabric, the fabric starts to char in a way that maintains the fabric’s strength and integrity to prevent a breakthrough in the fabric, which would expose the worker to much greater potential harm.
  
  
• Heat and Flame Resistance: FR fabrics are engineered to withstand extreme temperatures and self-extinguish when the flame/heat source is removed. Their initial resistance to ignition and the aforementioned char response buys the wearer precious seconds to get away from heat and flame. Any flames on the garment will quickly go out as the fabric self-extinguishes, greatly limiting the potential severity of injuries.
  
  
• Durability: FR fabrics not only have to withstand high temps and flame, but also physical threats to their integrity, like flying debris. They must also stand up to repeated heavy duty laundering and use, so these fabrics are made to be extremely durable for both resistance to daily wear and tear as well as to the more extreme tests of their strength presented by arc flash events.

Both FR fabrics made with inherent FR fibers, such as aramids and modacrylics, or by treatment with an FR finish can be appropriate choices for arc flash protection, provided they are rated for an appropriate level of protection for your application needs. Learn more about inherent FR fabrics here and treated FR here.

Arc flash hazards can be devastating, but when workers wear their FR garments properly and understand the limits of their protection, they can react appropriately in an emergency by getting away from heat and fire sources as quickly as possible to minimize the risk of greater harm.

It’s especially critical that workers understand that their FR workwear is not akin to a firefighting suit: they can’t stay in a fire for an extended period the way a firefighter would. The gear is simply not the same, nor is it built for the same purpose.

How FR Fabrics Protect Against Molten Metal Splash

In environments where workers regularly face the risk of molten metal splash, such as in welding or metalworking operations, the garments they wear must protect in the same ways garments protect against arc flash, but there is an additional consideration:

• Fabric Construction: The construction, or the twill, of FR fabrics is important for fabrics used to protect against molten metal splash. They are woven or knit in such a way that molten metal slides off the surface of the fabric rather than sticking to it. It goes without saying that molten metal is extremely hot, so by creating a fabric surface that molten metal rolls off like water beads off a raincoat, that hot metal is less likely to burn through the fabric.

Similarly to fabrics used for arc flash protection, FR fabrics for molten metal splash protection self-extinguish as fast as possible, allowing the wearer to remove the garment and avoid burns in case any molten metal has not yet rolled off the fabric.

How FR Fabrics Protect Against Flash Fires

If you’ve read this far, then good news! You already know the answer here. All the protective qualities we covered under arc flash protection apply to flash fire protection as well, and the ultimate goal of the protection is the same: to buy the wearer time to get away from the hazard.

By understanding the mechanisms of protection and the limits of that protection, you and your workers will be well equipped to handle arc flash, flash fire, and molten metal splash hazards with the correct response: to get away from the hazard as swiftly as possible. We may be repeating ourselves here, but when seconds can mean the difference between someone walking away from an incident and going home at the end of the day or not, it truly does bear repeating.

Looking for an FR workwear solution that will provide your workers with the best possible protection? Enter your requirements into our Fabric Selector tool here to get started, or reach out to a TenCate Protective Fabrics expert to chat about your safety program challenges: