Monthly Archives: April 2011

Yours, Mine or Ours — Who is Responsible for the Firestopping?

by Randy G. Clark

Since I first got my start in firestopping more than eighteen years ago, I have seen many changes take place within this very young industry. The number of manufacturers having listings for firestop systems has increased more than three-fold. The model codes have gone from unclear firestopping references to specific language within a section devoted exclusively to firestopping. With these code refinements came increased enforcement by the local building officials. Architects have become much more aware of the need to provide clear and specific details of the firestop conditions needed within their building designs. Mechanical, electrical, and plumbing engineers are now automatically incorporating proper firestopping techniques, which influence the design of their individual service runs. The types of products offered were only a few, but now they include: Sealants, putties, mortars, pillows, boards, wrap strips, devices, etc. Though there have been many changes, there seems to be one persistent questions: Whose responsibility is it to do the firestopping? Before we deal with this issue, we need to review the following: What is firestopping, why do we need to firestop, and how are firestopping materials tested?

One way to look at firestopping would be to say that it is a material or a combination of materials used to re-establish the fire integrity of a rated wall or floor assembly after its rating has been compromised by the inclusion or exclusion of a penetrant. To simplify, one must maintain the time rated integrity of an assembly after any alteration. As an example, when an insulated pipe is installed through a two hour rated gypsum wall, that pipe has destroyed the original rating of the wall. If the contractor follows a tested firestop configuration and properly installs the listed firestop materials, the original rating of the wall with its penetrant is maintained.

Why do we need to firestop? First of all, firestopping is one of the requirements of the various building codes. All major building codes have at their foundation fire codes. The integrity of a building during a fire condition must be maintained in order to have a safe evacuation of its occupants. The integrity also needs to be maintained in order to provide the firefighters their best opportunity to put out the fire. Secondly, firestopping is a matter of life safety. The lives of the firefighters as well as those of the building’s occupants could very well depend on having properly firestopped penetrations. Using a product which is part of a recognized firestop system configuration will meet the requirements of the codes.

How are firestopping materials tested and who is responsible will be covered later or see complete article.

 

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).