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Compartmentation is the term used to define a building being divided into fire zones. Each zone can contain an internal fire or resist an external fire for a specified time period. The walls and floor inside a zone are fire-rated for a specified time period to prevent smoke and fire from spreading to other areas.

The installation of a cabling system exposes a building to losing the integrity of its fire protection system. As the cable pathway is built above ceiling, the penetrations that are required for the passage of the cabling create an opening for fire and smoke to spread.

According to NEC Article 300.21, “openings around electrical penetrations through fire-resistant-rated walls, partitions, floors, or ceilings shall be firestopped using approved methods to maintain the fire-resistance rating.”

In case of fire, a properly installed firestop system is the first line of defense to prevent the spread of fire and smoke. BISCI best practices consist of the following items:

  • Determine the type of structure (e.g. wall, ceiling or combination) and the type of material to be penetrated (e.g. concrete, drywall, or wood).
  • Determine the number, size and types of cables to be placed (which will roughly define the size of the opening).
  • The size of the opening and the items penetrating the opening will define the annular measurement or space.
  • The construction and location of the fire-rated barrier will influence the methods for creating the opening. The pathway system (conduit/tray) and firestop assembly.
  • Other issues that impact the specific selection are: the hourly F rating to be supported, reuse of the pathway and method of placement.
  • The existing conditions on the jobsite – the its installer should try to match the existing conditions whenever possible.