Requirements for firestopping in building codes date to before the development of the International Building Code (IBC), which most states and local authorities follow today.
Although the IBC has gone through significant changes since its advent and not all types of construction require firestopping or fire-rated assemblies, one item that has stayed constant is that firestopping is required if a fire resistance-rated assembly is penetrated. IBC Chapter 7, “Fire and Smoke Protection Features,” outlines the requirements for fire resistance-rated assemblies and passive fire protection including firestopping for the various construction types. The sections in Chapter 7 provide detailed information on the minimum requirements for fire and smoke protection. (It is important to note that the IBC varies in content and requirements from version to version. The International Code Council, which develops the IBC, currently maintains a code-development cycle of three years. Because of the gap between code development and jurisdictional code adoption, the requirements will vary from state to state. Although the 2009 IBC is now available, some states are still using the 2003 or 2006 versions.)
The 2009 International Building Code provides requirements for firestopping in Sections 713 and 714, but in previous versions firestopping was located in Sections 712 and 713. The protection of penetrations of horizontal assemblies and fire resistance-rated wall assemblies is described in Section 713. Section 714 governs joints installed in or between fire resistance-rated assemblies and requires an approved fire resistance-rated system to be installed. The code requirements for firestop and smoke stop installations provide protection of the structure, and they also help maintain a minimum degree of protection for occupants who live or work in a structure and for fire safety personnel who must enter the building if a fire occurs.
A closer look at IBC (2009) Section 713 shows exactly what is required for protection when fire-resistant assemblies are penetrated. Section 722.214.171.124 states that through penetrations shall be installed and protected with an approved firestop system tested to ASTM E814 or UL 1479. The section also states that the fire-resistance rating of the firestop system (F rating) must be at least equal to the fire-resistance rating of the assembly penetrated. In Section 7126.96.36.199.2, the code goes further to state that through penetrations of fire resistance-rated floors must have F and T ratings of at least one hour, but not less than the fire resistance rating of the floor penetrated. The code contains an exception for the T rating if the penetrating item is concealed in a wall cavity. However, when selecting systems for floor penetrations, it is necessary to find an approved firestop system that satisfies the F rating as well as the T rating when both are required.
Section 710 in the 2009 IBC explains the protection requirements for smoke barriers in construction. It seems simple enough that a smoke barrier just needs to stop smoke, correct? Unfortunately, life is never that simple and neither is the building code. Smoke barriers are required to restrict the movement of smoke by definition, but when you look more closely you will see that Section 710.3 requires smoke barriers to also maintain a one-hour fire-resistance rating. Thus, if the smoke barrier assemblies must have a minimum one hour fire-resistance rating and must stop the movement of smoke, then what are the requirements for penetrations? All penetrations through smoke barrier assemblies must comply with Section 713, which, as mentioned, governs all firestopping for penetrations in the IBC. All penetrations in smoke barriers must be firestopped, but they also must stop smoke, which means that they need to have an L rating. Section 713.5 states that penetrations of smoke barriers must be tested to UL 1479 air-leakage testing and maintain an L rating of no more than 5 cubic feet per minute per square foot or 50 cubic feet per minute per any 100 square feet.
Understanding the specific requirements for construction that are prescribed in the building code is an elemental part of the construction process. Codes dictating passive fire protection ensure a minimum standard for passive life safety and property protection. The building codes are effective only when properly followed and enforced. No one wishes to be trapped in a burning building that was not firestopped to code. Maintaining minimum safety standards is what the building codes do for all of us.
Insert from “Stop Fire in its Tracks” by Riley Archer