Fire Rated Wall Systems: A Beginner’s Guide


Fire rated wall systems can be an extremely important part of your modular building project.  After all, having extra fire protection for employees or equipment can be essential to company safety. However, these fire ratings on wall systems can include a lot of different terminology and materials, and it can be difficult to grasp the entire concept.  That is why, we at Panel Built, have developed this little guide to help you familiarize yourself with fire rate wall systems, and the terminology that goes into it. Fire Rated Wall Panel


One Hour Fire RatedTerminology

                                                                                                                                                    Fuel Contribution – The amount of heat energy that building material can give off to a fire. Flame Spread Rating – This rating refers to a materials “propensity to burn,” and spread flames across the material.  The rating does not refer to a fire spread per feet, but is just an arbitrary scale to allow relative comparisons among materials. The index is measured on a scale of 0-100 with 0 being asbestos-cement board and 100 being red oak wood.(National fire protection agency) Smoke Developed Index – Simply refers the concentration of smoke that a piece of material will emit while it burns.  Similar to flame spread, the smoke developed index is an arbitrary scale that allows comparisons among materials. Class A Rating – Materials that receive a Class A rating will not sustain a flame, however they may still ignite. Class A rated materials are rating higher in comparison to Class B & C because they do not create an undue vision blocking smoke. These types of materials have a 0-25 on the flame spread index. No material can be considered Class A with a smoke developed index over 450. Non-Combustible – Refers to materials that will not contribute to a flame.  This type of wall paneling will not burn or contribute to the size of the fire by itself. This designation provies a higher resistance to fire than a Class A Rating. 1 Hour Fire Rated – Refers to an assembly that can withstand a standardized (ASTM) fire exposure for up to an hour long. After this, the wall is sprayed with water from a fire hose. If the wall withstands the hosing, it passes.

Why is this Important?

There are two reasons to know and understand fire ratings, one very obvious and one that’s perhaps not so obvious. Fire Rated Modular BuildingFirst, understanding the fire rating of your building or structure is vital to the protection of your employees and equipment. Especially in a higher risk environment, knowing the ratings of your wall panels will provide you with better safety, and actually allow you to execute your fire escape plan more efficiently. And on top of that, the higher the fire rating of your walls, the longer they will resist the flame and protect what’s inside the building. Second, insurance companies will often require that buildings that come in contact with flammable materials receive higher fire ratings.  If your warehouse holds flammable liquids (any liquid with a flashpoint at or below 199.4o), your insurance company could require any interior office buildings to hold a fire rating of Class A to a 1 Hour Fire Rating.

How Can Panel Built Help?

Panel Built, Inc. offers a number of different fire rated panels One Hour Fire Ratedto satisfy all of your fire safety and protection needs.  Our Class A option contains a polystyrene core with a vinyl covered gypsum board.  Our 1 Hour Fire Rated option Mineral wool core covered by mechanically fastened type-x gypsum board to 26 gauge steel studs. At the end of the day, your insurance company will oftentimes have a lot of influence on the type of paneling you will be using for your structure.  If they require you to have a system higher than a Class A, but not quite 1 Hour Fire Rated, we have created a hybrid, non-combustible panel that lies between the two and has characteristics of both. This Non-Combustible Paneling option is gypsum covered mineral wool core, which can be laminated together with adhesive. Panel Built has constructed a number of different fire rated systems for both military and commercial customers all over the United States. All of our fire rated panels have been laboratory tested to ensure they meet or exceed all fire safety regulations and standards. And we personally guarantee consistent, overwhelming quality from our products. If you would like to know more about the different types of panels we offer, or have a question about which is right for your situation, send us an email at, or get in touch with one of our sales reps; they’re always more than happy to help with any of your modular building needs. And, as always, we offer all of our potential customers a free quote on their modular construction projects.