THE FIRE RESISTANT GLOVES: WHAT YOU SHOULD KNOW
Fire related hand injuries
Fire injuries occur when hands are exposed to direct or indirect flame, and—combined with the heat present—cause burn injuries. The depth of the skin damage determines the severity of the injury, anywhere from first-degree burns (surface damage to the epidermis) to third-degree burns (leaving the skin charred and causing nerve damage).
Fire-resistant (FR) gloves, designed to resist heat and flame exposure, are made from materials that can withstand high temperatures and prevent heat transfer to the wearer’s hands.
Forces at work in a fire-resistant glove
To understand fire resistance in gloves, we must first identify the ingredients that cause fire and how to counteract the effects.
The fire triangle
The fire triangle displays the three necessary components needed to ignite and sustain a fire. These include:
This is why fire-resistant gloves need to be made with materials that:
- Resist ignition or combustion
- Limit the area that catches fire
- Minimize the transfer of heat to the hands
- Do not sustain fire once the ignition source is removed
Note: Every material has a melting point and every material will eventually ignite and catch fire. What is important is how much of that material will burn over time and how quickly it extinguishes itself.
Materials used in fire-resistant gloves
FR materials are either treated to resist flames or made from inherently fire-resistant materials. The most common material used for protection against fire hazards is leather, due to its inherent fire resistance and durability. However, other materials are also used to manufacture fire-resistant gloves.
Leather is inherently fire resistant and a frontrunner to protect against fire. Its solid outer shell provides a natural barrier that makes it hard for flames or heat to penetrate.
Cotton is a natural fiber that provides natural heat resistance. However, cotton must be treated with chemicals that resist fire in order to be fire resistant. Like wool and modacrylic, cotton is most commonly used as a liner in leather and knit gloves for extra protection and comfort against fire hazards.
Modacrylic is a synthetic fiber that is inherently fire resistant. But, unlike aramids, it lacks any type of mechanical protection. This is why modacrylic is often blended with other materials (natural or synthetic) to improve mechanical protection and comfort.
Wool is an inherently fire-resistant natural fiber that forms an insulating layer to prevent flames from spreading further. It is not flammable and has a very high ignition temperature, preventing it from easily catching fire. If it does catch fire the wool will burn slowly and, when the fire source is removed, the fibers self-extinguish. For FR gloves, wool is often used as an inner liner in leather and knit gloves for extra protection and comfort.
Besides being inherently fire-resistant, wool is commonly used as an insulating liner that helps keep hands warm while working in cold temperatures.
Both major aramids—para-aramid and meta-aramid—are synthetic fibers that are inherently fire resistant due to their chemical structure. For FR gloves, aramids are often selected because of their superior natural mechanical protection, particularly para-aramids, since they offer protection against other hazards, such as cut and abrasion. Aramids are also frequently paired with leather to improve its natural flame and heat resistance.
Polymer coatings are synthetic materials traditionally used for manufacturing chemical gloves and also serve as palm coatings for knit gloves. Common materials used for tasks involving fire hazards are:
· PVC: Synthetic plastic material and naturally fire resistant. PVC offers natural resistance to a lot of chemicals and is ideal for working in frigid temperature as it won’t stiffen.
· Neoprene: Synthetic rubber material and naturally fire resistant. Neoprene is primarily used for its natural high fire resistance. For instance, manufacturers use neoprene palm coatings in knit gloves to achieve arc flash protection (a more severe form of fire hazard).
· Silicone: Synthetic rubber material and naturally fire resistant. It offers high heat resistance, as it has a very high melting point, and good abrasion and puncture resistance. It is also adhesive resistant.
1. Inherently fire-resistant materials are better for fire resistance in the long term because treated materials eventually lose their fire-resistant properties from wear and washing.
2. As noted earlier, every material has a melting point and every material will eventually ignite and catch fire. What is important is how much of that material will burn over time and how quickly it extinguishes itself.
Vertical Flame Test
Test ASTM D6413 is the standard test method used to determine fire resistance—also known as the Vertical Flame Test. This test aims to determine whether a fabric will continue to burn after the source of ignition (flame) is removed and to determine if any dripping or melting occurs. Performing the test involves using a swatch of the material enclosed and secured in a chamber. The bottom of the fabric is then exposed to a controlled flame for 12 seconds after which the flame is extinguished. At that point, the fabric is studied and measured to gauge:
1. AFTER FLAME
Seconds during which there is visible flame after the source of ignition is removed. After flame cannot exceed 2 seconds (i.e., the fabric must self-extinguish within 2 seconds).
2. CHAR LENGTH
The length of fabric destroyed by the flame. Char Length cannot exceed 102 mm (approx. 4 inches).
3. MELTING OR DRIPPING
No melting or dripping of the fabric can occur.
If the fabric achieves the criteria listed above, it is deemed fire resistant.