Fire Stopping Existing Cables: Split Sleeve Advantages


Retrofitting low voltage violations with “approved” or “tested” systems has left a lot to be desired in the past. Most systems dealt only with point of entry and exit. Simply filling in around installed cables with caulk or putty will not satisfy most inspectors. If the cables in question are running equipment that can’t be shut down, like computer systems in hospitals or factories, security cameras or other important systems, you have a problem.

The days of getting off with a slap on the wrist are over — as well as the old tradition of “mudding” around your violation. In today’s commercial building environment you will need to prepare to meet and make happy the fire marshall, the local building inspector, as well as the county inspectors (known collectively as the Authority Having Jurisdiction or the AHJ).

Through penetrations in firewalls should be:

  1. Functional
  2. Easily installed
  3. Re-enterable
  4. Reasonably priced


The Split Sleeve Fire Stop made by Unique Fire Stop Products was invented for exactly these kinds of problems in existing installations in firewalls.


The system is manufactured as a 12 inch section of rigid conduit that is threaded on the outside and split down its axis. The two halves act as outer casings around the cables. A pair of slotted washers are worked over the cables, over the assembled sleeve and against the fire wall with the slots 180 degrees from each other. A slotted coupler (nut) is provided for each side to keep the two threaded halves together and to secure the washers to the wall.

After the sleeve is installed around the cables, the installer will stuff the end with wool batt insulation and finish the job with a minimum of one inch of Fire Stop Putty, applied in front of the insulation to form a seal flush with the end of the sleeve. Additional cables can be added later.

Split Sleeve Systems are available in one inch for a few cables, or two and four inch systems for small and medium size cable bundles. A bulkhead plate has been developed for larger holes and can be ordered in any size or configuration.

For visual, step-by-step instructions, see our Installation Pictorial for the Unique Split Sleeve Fire Stop System.