Monday, March 6, 2017

Protecting Cable Sleeve Penetrations

An often overlooked, but critical component of building and occupant fire safety is fire barriers, and fire-resistance-rated construction. Beyond reasons of code requirements, fire-rated barriers are an essential component of a buildings life safety system.  These barriers work in conjunction with the sprinkler system to ensure that a fire cannot grow beyond the sprinklers capacity, they provide an area of refuge, and they allow time for occupants to egress a structure. To be effective, these fire barriers must be installed in accordance with their listing, and be free of any openings that could allow for the transport of smoke, heat, and fire from one side to the the other.


Throughout the construction process and the building's lifespan it becomes necessary to penetrate these barriers due to installation of building systems and components. In today's ‘connected’ buildings a main source of these penetrations comes from the need for network cabling to support data and communications networks.




Shows Overfilled Sleeves with firestop only installed on the top side of the sleeve.


Model codes have recognized that this will occur, and have included the following code language in their texts:


NFPA 101:8.3.5.1 - “Penetrations for cables...to accommodate...communications systems shall be protected by a fire stop system or device…”


IFC 703.1 - “Openings made therein [in fire-resistance-rated construction] for the passage of pipes...wires...and holes made for any reason shall be protected with approved methods capable of resisting the passage of smoke and fire.”


As cable networks expand, often times firestop materials are removed and not replaced.  As new cable displaces the firestop system, eventually the system is rendered non-code compliant. Fire inspection personnel should be aware of these conditions and ensure that cable sleeves are properly sealed and the fire-resistance-rating of the floor or wall assembly remains intact.
Here is a checklist of items that can be used to measure the reliability of a properly sealed cable sleeve:
  • The third-party tested and listed firestop systems will specify the permissible cable load.
  • The cable load for standard cable sleeves is calculated.  The calculated cable load is the aggregate cross-sectional area of cables as a percentage of the aggregate cross-sectional area of the sleeve.  What may appear to be a 50% visual fill, might actually be half that when calculated due to interstitial space between grouped cables.
  • Sleeves with missing or partially removed firestopping need to be repaired and cable fill percentage for the listed firestop system should be verified to ensure system remains compliant.
  • Firestop systems are mostly installed symmetrically on both sides of the wall or on top side of the floor.  However, listed firestop systems will provide greater detail.
  • Firestop materials are often red, but do not necessarily have to be.  There are no code related requirements that dictate color.
  • Listed and labeled purpose-made devices with integrated firestopping systems are available to replace traditional cable sleeves or to retrofit existing sleeves.
With the myriad of items that a fire inspector is responsible for looking at, this can prove to be one of the most critical. Having a clear understanding of fire-resistance-rated construction, fire stopping materials, and listed systems and components, can provide a more clear perspective on what to look for during inspection.  
Additional Resources