Tag Archives: firestopping

Requirements for Firestopping

firestoppingCODE REQUIREMENTS

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.

Penetrations

A closer look at IBC (2009) Section 713 shows exactly what is required for protection when fire-resistant assemblies are penetrated. Section 713.3.1.2 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 713.4.1.1.2, 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.

Smoke Barriers

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

 

Stop Fire in its Tracks

by Riley Archer

You may have heard the word firestopping thrown around the construction industry to describe any material used to prevent the spread of fire—but what is it really? A firestop is a material or combination of materials designed to reestablish the fire-resistance rating of rated assemblies such as fire-rated walls, floors, and ceilings. These materials or systems are required to be fire tested and listed by an accredited, independent testing agency as proof of their performance in fire conditions.

The use of firestopping is different than the use of fireproofing, fireblocking, and firesafing, but unfortunately these terms often are confused and incorrectly used as interchangeable. Fireproofing applications deal primarily with the passive fire protection of the structural steel elements of a building. Fireblocking is the process of installing materials to resist the free passage of flames in a building through concealed spaces. Firesafing generally refers to the fire-resistant insulation that sometimes is used as part of a firestop system.

Firestopping is when a fire resistance-rated assembly is penetrated or a void is created due to the inclusion of a construction joint, a firestop system must be installed properly to reinstate the original fire-resistance rating of that assembly.

To create a firestop system, all of the materials must be installed in a rated assembly and fire tested for integrity in the exact configuration in which they will be installed. The most widely recognized third-party agency for fire testing is Underwriters Laboratories (UL), which tests, classifies, and lists firestop systems and materials as well as numerous other products used on a daily basis. The duration of the fire exposure testing depends on the rating of the assembly construction and the desired hourly rating of the system that is being tested.

The assemblies also must pass a water hose stream test.

Penetration fire tests provide data on the duration of time for which the assembly prevents the passage of flames, or F rating, as well as the duration of time during which the nonfire side of the assembly and penetrant reach 325°F over ambient temperature, or T rating. The significance of the T rating is that it provides a point at which combustible materials on the non-fire side of the rated assembly will catch fire due to temperature rise.

Two optional ratings also are available through the UL 1479 test standard: a W rating, provided by a water-leakage test, and an L rating, provided by air-leakage testing. If a firestop system is W rated, it means the system has a water-resistive seal while still maintaining the fire-resistance rating of the assembly. The water-leakage test is conducted using a minimum pressure of 3 feet of water for a duration of 72 hours. The L rating measures the air movement through the firestop assembly at ambient air temperature (75°F) and at a temperature elevated to 325°F above ambient (400°F).