Install fire barriers within the tray to isolate different fire zones. When cable trays pass through walls or floors, seal openings using fire-rated penetration sealing materials. Route Planning and Layout Principles Coordinate with Building Structure: Cable tray routing should align with architectural design, avoiding unnecessary. The following charts give the number of 3M pillows needed to completely firestop an opening that cable tray passes through. One of the most commonly recurring non-compliances seen during an annual assessment is the absence, or inadequate sealing, of cable. FireResistant Solutions provides cable tray covering and fire-protection systems designed to safeguard electrical and data infrastructure in commercial and multifamily buildings.