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Flame Retardant Duct

A Vital Safety Feature in Today’s Industry


Fire is a universal danger. Whether it is home, commercial, or industrial environments, fire poses an extreme threat that can take innocent lives and cost thousands of dollars in prevention and repairs. Fortunately, as technology advances so do methods of preventing fires. One method of fire prevention is through the use of flame retardant materials. Flame retardant duct products are now commonly used in many homes, businesses, and industries to create a safer environment and prevent against potential fire hazards. There are many fire rated duct products available to consumers and it is important to understand exactly what flame retardant tubing can do for you.

One important thing to note is the difference between products that are described as flame retardant and flame resistant. When looking for products that will provide protection against the threat of fire hazards, you will often see different products claiming that they are either one of the two classifications. Unfortunately, it is a common misconception that the description of fire retardant and resistance are actually one in the same. The difference is that “flame resistant” is a term commonly given to a material that will not burn and “flame retardant” means that the material itself will not act as fuel and if the source of fuel is removed the flame retardant material will not burn.

Fire fighters commonly use flame retardant chemicals when trying to prevent the spread of wildfires in flammable brush lands. They are also utilized in hand held fire extinguishers. These chemicals are also incorporated in the construction of many ducting materials. Flame retardant tubing is important when working applications where open flames, high temperature and fumes, and flammable chemicals are used.

Fire rated duct products work in two ways, they either create protection from flames physically or through a chemical reaction. Physical protection occurs through cooling, dilution, or the formation of a protective layer. The flame retardant coating used on some products contains a chemical that can actually bring down the temperature of the fire source, effectively crippling its ability to spread to other fuel sources. Also, the chemicals used in the coating can release water or carbon dioxide when exposed to the flame, which can actually work to extinguish a small enough flame. Finally, the flame retardant ducts form a protective barrier that serves as a shield between the fire and the ducting material so that it will not burn when a flame comes into direct contact with the hose. The retardant coating provides chemical protection through reactions through four different methods: the gas phase, reactions in the solid phase, creating a char formation, and through the use of intumescents. Reactions in the gas phase can create a chemical reaction within the flame. In the case of a gas phase, the flame is interrupted by the fire retardants, effectively cutting off the fuel from the fire.

The flame retardant tubing can also create a reaction in the solid phase by breaking down its own polymers and melting away from the flame, which eliminates the fuel source from the fire. Solid phase flame-retardants create a layer of carbonaceous char to form on the ducting’s surface to protect the base of the material. The char is more difficult to burn and serves as a layer of protection to the base material. Some flame-retardants feature intumescents. These products feature chemicals that cause swelling to form behind the char to effectively create two fire resistant barriers between the flame and the base material.

In order to be classified as flame retardant, the material needs to go through a series of tests. UL 94 flame classification tests the tendency a material has to either extinguish or spread the flame once the two come into contact with each other. UL 94 testing consists of testing the material in horizontal and vertical positions. Testing professionals will place the flame retardant ducts in several different vertical and horizontal positions to test how the flames react when they come into contact with the material. These tests progressively increase the intensity of a flame in order to determine what grade the fire rated duct coating will receive out of a possibility of 12 different ratings. 5VA, 5VB, V-0, V-1, V-2, and HB ratings are related to materials that are commonly used in enclosures, structural parts and consumer electronics. HF-1, HF-2, and HBF ratings are related to foam based materials. VTM-0, VTM-1 and VTM-2 ratings are for extremely thin materials that are not capable of supporting themselves. For electrical applications, the UL 746A test determines the materials ability to resist igniting into flames when exposed to an electrical source.

In order to provide necessary protection from fire hazards, we offer several products made of materials that have gone through testing and are classified as UL 94 flame retardant tubing. These products range from low temperature and light-duty tools to extremely heat resistant and heavy-duty. We have several flexible PVC and polyester hoses that are suitable for temperatures up to 180 degrees Fahrenheit. Several of our mid-range products are also coated in a fire rated duct neoprene material, which provides resistance to temperatures up to 250 degrees Fahrenheit and great level of resistance to chemicals and electrical currents. Stainless steel options are also available and they are capable of resisting temperatures up to 1650 degrees Fahrenheit. Along with extreme heat and fire resistance, our metal alloy ducting products offer great resistance to weathering and crush resistance.

Flame retardant ducts offer extra protection for applications dealing with high temperatures and potential fire hazards. Utilizing fire rated duct products containing materials with the ability to resist fire provides an application with an extra degree of safety that protects your products and workers’ safety, as well as ensuring maximum efficiency.