FSI – FAQ

What is firestop? Firestop is a term used to describe the use of building materials to prevent the spread of flames, smoke, or gases through penetrations, gaps and joints in fire-rated floors, walls, and floor/ceiling assemblies.

What is a firestop system? Firestop systems are combinations of products and materials, installed to a tested and rated specification, to prevent the passage of fire, smoke and gases between compartments of a building.

What is a containment/compartmented space? Firestop systems were developed to produce a containment/compartmented space, restricting fire, smoke and gases from entering the protected area. These spaces are protected by fire-rated wall and floor assemblies. All penetrations, gaps and joints in the assembly are sealed with tested and listed firestop systems to return the integrity to the rated wall or floor system.

Is mineral wool 1-hour rated? Mineral wool by itself cannot be used as a firestop. Mineral wool can allow fire, smoke and toxic gases to pass from one compartment to another. Mineral wool, by itself, does not stand up one of the requirement of both ASTM-119 and ASTM-E-814 which specifies the “hose stream test”. However, mineral wool installed in conjunction with a firestop caulk or sealant, can be an effective component of a firestop system if installed within the parameters of a specific tested or engineered firestop design.

Is firestop as simple as 1-hour – 1 side, 2-hour – 2 sides? No, unfortunately it is not that simple. Both sides of a wall must be firestopped with an equally rated system 1-hour for 1-hour, 2 for 2, etc. A floor installation can get tricky. 1 & 2 hour ratings usually require one side of the floor to be firestopped. 3 & 4 hour ratings can require both sides depending on the systems’ manufacturer. It is very important to note when firestopping a floor, metallic penetrations are usually done from the top of the floor and non-metallic penetrations are almost always done from the bottom of the floor. Floor/Ceiling assemblies (wood frame) require firestop systems at the top and bottom plates.

Which is better 1-hour or 2-hour caulk? Firestopping is not about products nor manufacturers, but about tested and listed systems. Products by themselves carry no rating. It is the combination of specific application instructions and the use of specific products that establish the “firestop system” rating.

I have plastic pipes, will any system work? It is very important to understand that plastic is not a generic term when it comes to selecting a firestop system. Non-metallic (plastic pipe) systems are tested with specific types of materials (ie: PVC, CPVC, CCPVC, ABS, FRP, PVDF) these materials react differently when exposed to fire and heat. A contractor must ensure that the system to be installed is tested for the specific type of penetrant.

Do I really need firestop? Any property owner or builder should be concerned about liability issues relating to property damage, injury or death by uncontained fire, smoke, and/or deadly gases. If the integrity of fire-rated walls, ceilings, or floors is compromised by penetrations, then a firestop system is required.

I have a sprinkler system – do I need a firestop system? Sprinkler systems are extremely important and are a key component of the “Life Safety System”. However, it is important to remember that sprinkler systems suppress rather than contain fire. Sprinklers are useless against smoke and deadly gases. As nearly 70% of fire-related deaths are caused by smoke inhalation, the need for a firestop system is even more critical.

What types of firestop systems are there? There are over 8,000 tested systems. The type of system needed is determined by the location, substrate and application (construction joint, plastic pipe, cable tray, grease duct, etc.). The U.L. Fire Resistive Directory is designed to list tested systems, in an Alpha-Alpha-Numeric sequence for each typical building service application.

What is ASTM E-814? It is the recognized industry standard that evaluates through penetration firestop systems in fire-rated floor, wall, or floor/ceiling assemblies. The test establishes ratings listed as “F”, “T” and “L” Ratings . The purpose of the test is to return the floor, wall or floor/ceiling assembly to the original fire rating.

What do the “F”, “T” and “L” ratings mean? An “F” Rating indicates the amount of time that a firestop system can withstand fire before allowing the passage of flame through an opening. A “T” Rating indicates the amount of time it takes the temperature on the non-fire side of the assembly to exceed 3,250 degrees Fahrenheit above ambient temperature. An “L” Rating indicates the amount of air leakage (in cubic feet per minute) through a penetration (this is the industry’s solution to “smoke sealing”).

What do the terms intumescent, endothermic and elastomeric mean? An intumescent material, when exposed to heat, expands to fill a void. An endothermic material blocks heat by chemical absorption and moisture release. Elastomeric materials are flexible and allow movement of the assembly while preventing the passage of fire, smoke and toxic gases.

What does “approved methods” mean? It is a term that refers to firestop systems that have been tested by an independent laboratory (e.g., Underwriters Laboratory) that meet ASTM E 814 criteria.

What are “Engineering Judgments”? “EJ”s are recommendations manufacturers make to meet actual field conditions, based on testing that approximates the job-site conditions.

Is spray-on fireproofing, joint compound or mortar an adequate firestop in construction joints? NO! All material used in firestopping joints such as top or head of wall, perimeter/curtain-wall gap, control joints, etc. will have to pass a cyclical test (500-cycles – UL 2079) and then pass the fire and hose stream test in a fully extended situation. This means that cementitious fireproofing, tape/joint compound or firestopping mortar (typically pink, red, or brown) that is commonly used by drywall contractors at the head of sheetrock walls will not work. The problem with these types of materials is that with any movement of the assembly, cracks occur which can allow fire, smoke and toxic fumes through. A material that has expansion and compression characteristics is required.

Can I substitute or mix manufacturers’ products in the system? No! Substituting products within a firestop system compromises the integrity of the system. Systems are tested with a single manufacturer’s products to a specific design criteria. Substituting or mixing other manufacturer’s products will not fulfill the system requirements, and could potentially jeopardize life and property.

Is firestopping expensive? Careful planning, during the design phase and before the start of construction, can reduce the costs considerably. However, it is typical that contractors do not budget adequate funding to cover the cost of proper firestopping. At the completion of a job when the building inspector finds that firestop systems are either installed incorrectly or are totally missing, the cost can become extreme. A last-minute rush is usually what makes firestopping truly expensive.