Forty years ago, when I started practicing engineering, through penetration firestops were very simple. Once the opening through the fire barrier was made, and the pipe or other item was installed, the annular space was "stuffed" with a non-combustible material such as mineral wool, fiberglass, or heaven forbid, asbestos this was before asbestos was known to be a carcinogen. In , a fire at the Browns Ferry Nuclear Plant demonstrated that it was not only important to seal penetrations to limit the spread of fire, but also to limit the spread of smoke. Previously used materials were found to be inadequate for this purpose. As a result of the fire, Dow Corning Corp. Subsequent to this initial development, a series of tests were developed for testing these materials in combination with various fire barrier constructions, resulting in the Underwriters Laboratories UL Fire Resistance Directory, containing 1, pages of through penetration firestop systems.
Stuff It--A Guide to Through Penetration Firestop Systems
Fire Stopping: What Every Contractor Needs to Know | Electrical Contractor Magazine
Penetration firestopping systems and fire resistive joint systems are a passive means of fire protection. There is no movement or activation required. These passive systems are mainly used to compartmentalize a fire and keep it from spreading for a period of time long enough that occupants can evacuate the building and so firefighters can perform initial lifesaving tasks. Modern buildings are full of various services that travel from room to room throughout a building. Electrical cables, data cables, and plumbing pipes are few of the items that pass through walls as they travel through a building.
Through Penetration Firestop and Fire Resistive Joint Systems
UL standards require successful testing of all approved through-penetration firestops designed for use in breaches in firewalls or floor-ceiling assemblies, or both. The UL tests required by Underwriters Laboratories determine the ability of a firestop system to stop the spread of fire, smoke, and water through a fire-rated barrier in the event of a fire and for how long a period of time. Building codes require the use of firestop systems tested and approved under the UL standard, Fire Tests of Through-Penetration Firestops.
For approximately 40 years, unprotected or improperly protected penetrations have presented a subject of much concern to the fire-protection community. The arriving firefighters discovered several fires had broken out in five remote locations, filling many different areas of the building with smoke. According to the National Fire Protection Association's report on the fire, unprotected vertical and horizontal penetrations provided one of the major contributing causes of the rapid, erratic spread of smoke and fire. These openings allowed the smoke to spread beyond the electrical rooms and into occupied floors.