Fire Caulk Installation

Fire caulk installation is a process that is governed by federal, state and local building codes, as well as manufacturer specifications. It’s important to remember that in any instance of modifications or upgrades to your house, that local codes take precedence over federal and state codes, if they are more stringent than the federal or state codes. In order to meet codes and manufacturer requirements, the installation of fire caulk when penetrating a wall or floor must be done in a specific way. All penetrations through fire barriers walls must be made using approved methods. This means some sort of fire resistant piping must be used for the penetration. If the penetration is made to bring wires or cables from one room to another, then a piece of conduit or EMT must be used. This article will address the installation of fire caulking in and around a piece of EMT conduit with low voltage data cables in it.

Required Materials

Besides the cables you’re stringing, you will need 3 things for the proper installation of fire caulk.

  • A piece of EMT conduit large enough to accommodate the cables and approximately 4 inches in length.
  • Fire caulk
  • Mineral wool batting.
  • Latex or polyvinyl gloves


The steps provided below are generic ones. Please refer to the package labeling for exact specifications on thickness of mineral wool batting stuffing and fire caulk. These instructions will presume the use of moldable putty fire caulk.

  1. When making your penetration, make sure the hole you make is just big enough for the piece of EMT/conduit you’re using.
  2. Insert the piece of EMT/conduit in the penetration you’ve made.
  3. Pull your cables through the conduit.
  4. Put on the gloves.
  5. Insert enough mineral wool batting into the pipe to create a wall a minimum of 1 inch thick on either side and make sure the cables are as centered in the pipe as you can make them.
  6. Remove the paper wrapping on the block of fire caulk putty.
  7. Tear off a chunk of putty and work it until it’s easy to work with.
  8. Roll the chunk into a tube-shape.
  9. Insert the putty tube into the pipe with your wires, keeping the wires centered.
  10. Make sure there are minimal gaps where there is no putty.
  11. You should have a minimum of 1 inch of putty inside the pipe and approximately ½ to ¾ of an inch outside the pipe.
  12. Tear of another slightly larger chunk of putty and work until malleable.
  13. Roll this new chunk into a tube.
  14. Press the tube into the gap between the wall and the penetrating conduit.
  15. Smooth the putty around the pipe so that there is ½ inch on the wall beyond the hold and ½-inch minimum on the pipe outside the penetration.
  16. Repeat steps 5 through 15 on the other side of the wall.

Properly installed fire caulking can keep a serious fire from becoming disastrous or catastrophic. Incorrectly installed fire caulking will be next to useless. Be sure to check packaging for specific dimensions of mineral wool batting and fire caulk.