Firestopping Penetrations: Much More Than Red Caulk!

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Jay Peters

by Jay Peters, principal advisor, Codes and Standards International

Everyday across the globe, injuries, deaths and property destruction result from fire related events in structures. Interestingly enough these fires occur even though there were fire safety precautions incorporated into the buildings – from sprinkler systems to firestopping of wall, floor and ceilings penetrations. Just as important to consider is the fact that many of these structural losses, and the associated tragedy, is thwarted every day due to these safety precautions being installed – correctly.

A raging building fire will use any opportunity to circulate deadly gases, toxic smoke, and flames through penetrations into areas that were supposed to be protected – even the smallest opening or seam around a plumbing pipe, conduit or wire can become a direct passage.

Firestopping is a fire defense system that is critical yet often times not given credit for its importance in preventing loss of life by preventing products of combustion from spreading throughout a building. It is not an “active” fire suppression system such as a sprinkler system designed to extinguish a fire once started, but rather a “passive” firestopping system that is intended to contain a fire from spreading flame and smoke.

Just as contractors and installers consider their individual trades (plumbing, HVAC, etc.) to be held sacred, scientific and precise, the act of installing these important life safety products should be considered to be just as important to maintaining the integrity of the structure while reducing risk to occupants and the building. In fact, firestopping crosses all trades and industries on the job site and is as important as any other trade to contributing to the overall durability and reliability of the final structure.

The Basics

 A firestop system consists of materials installed and intended to retain the integrity of fire-resistance rated construction components by maintaining an effective barrier against the spread of flame, smoke and hot gases from breeching the structural member through penetrations or gaps in walls, ceilings and floors caused by other components, such as piping, conduit, cables and wires or building seams.

Just as a trained installer can save a contractor on the job thousands of dollars in the long run, a job that is not manned by a trained installer could cost as much or more in time and money. Many times a special inspector is charged with verifying compliance during and after the installation is complete. A savvy inspector, steeped in the intricacies of firestop materials and penetrations is a caulk-and-walk firestop installer’s worst nightmare. Before grabbing a caulking gun, a tube of red caulk, some mineral wool and heading to the job site to save some money, it is important to understand that it is much more complicated. In fact, there are thousands of different types of systems and installation methods created by many different manufacturers. Typically, there are several diverse and different systems on the same job site and more than a basic understanding is necessary to be a competent installer.

Firestopping materials are specialized systems and consist of materials that differ from manufacturer to manufacturer. Manufacturers such as 3M, Hilti and STI, have diverse and differing product lines made of everything from intumescent and endothermic caulks, to solid strips of materials, variations of cement and putty-like material. They have ratings that are imperative to understand and apply accordingly to the types of penetrations and material penetrating the walls ceilings roofs and floors. The appropriate “F” and “T” ratings should be understood and chosen.

If it is an afterthought, it’s too late

Does it matter what type of building material is penetrating the wall when choosing the firestop system? Of course it does. One firestop material does not fit all applications. A polyvinyl chloride (PVC) or acrylonitrile-butadiene-styrene (ABS) drain, waste, or vent (DWV) piping system needs much more intricate and expensive protection than a cast iron pipe penetrating the same wall, due to the fact that they are combustible materials. A contractor or designer should evaluate the true installed cost to protect each of these different penetrations at the beginning of the project and not treat this as an afterthought. In fact, using the plastic and cast iron example, a contractor may evaluate and find it less expensive on the material cost to use a plastic DWV piping system rather than cast iron piping system, only to discover that it would have been less expensive to have chosen the cast iron plumbing system due to the added expense of the complex firestopping systems required for plastic pipe penetrations.

Firestopping is one of the most misunderstood areas in construction. For example, an installation can be the correct firestop, but the wrong application. It’s important to know the proper system for the right application as there are intricacies that require knowledge and skill in their installation and inspection. Do not make firestop an afterthought. It is not just a tube of red caulk and some rock wool.

Caulk - Firestop
Above: No firestopping product has an hour rating on its own. The hour rating is determined by the Listed System and must be installed in accordance with the appropriate listing for the correct application. Remember, while a tube of caulk may say it can provide up to 4 hours of protection that is only true when installed as the appropriate listing states.

Safe installations will contain materials that are tested and listed to meet the industry standards created by standards developers, such as Underwriters Laboratories (UL), Factory Mutual (FM) and the American Society for Testing and Materials (ASTM). They will be installed by contractors and installers that are trained by leading industry trade associations such as the Firestop Contractors International Association (FCIA) and the end product will be inspected by agencies and inspectors that are accredited by the International Accreditation Service and International Firestop Council (IFC).


When completed correctly, the penetrations should be protected and follow the strict code provisions contained within the building, fire, electrical, plumbing and mechanical codes authored by the International Code Council (ICC), the National Fire Protection Association (NFPA) and the International Association of Plumbing and Mechanical Officials (IAPMO).

Below: A simple firestop caulk to protect annular space with cast iron piping.

Cast Iron - Caulk Firestop

Below: A firestop device collar as part of a complex firestop system that is required for protection of polyvinyl chloride piping.

Firestop - collar PVC

More questions than answers?

If you can’t answer these questions then you either need more training or additional help from a certified firestop company.

  • Is the Installing contractor licensed?
  • Is the contractor’s installer trained and certified?
  • Is the right combination of systems installed? In the correct locations?
  • Is it certified or listed for the application and type of penetration?
  • Has the system been inspected per the building code?
  • Is the inspector certified to inspect the intricate systems and identify the proper certifications? Has a log been made of every firestop penetration system?
  • Is there a maintenance inspection plan in place?


If you are not trained, licensed, certified or experienced in the intricacies of inspecting or installing complex firestop systems in a structure, it is simple…either get trained, or just don’t take on the risk! More than just saving money, a properly planned, installed and inspected firestop system saves lives.

About the author Jay Peters

For more than 35 years, Peters has been active in the plumbing and mechanical trades as a journeyman, contractor, instructor, and senior staff for ICC and IAPMO. His firm, Codes and Standards International, represents manufacturers and industry stakeholders at technical codes and standards meet- ings, regulatory, and legislative hearings; and navigation of product testing, listing, and certification processes at ICC, IAPMO, NSF, UL and more. He can be reached directly at jay@b uildingc

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