When cable trays pass through walls or floors, seal openings using fire-rated penetration sealing materials. Do not modify or damage the tray coating or structure during use. Adhering to IS 1255:1983, the following step-by-step procedure ensures proper installation of a 1200mm wide cable tray in a. RECOMENDATIONS BE APPROX. 6" LARGER THAN THE OUTSIDE DIM. OF CABLE TRAY FIRE SEALANT BAGS (SEE NOTE #1) BAGS SHALL BE: GRACE CONSTRUCTION PRODUCTS KBS SEALBAGS OR 3M FIRE BARRIER PILLOWS. INSTALL BAGS PER MANUFACTURERS INSTRUCTIONS TO ACHIEVE UL CLASSIFIED FIRE RATING EQUAL TO OR GREATER THAN FIRE. The resulting barrier retards the transmission of smoke, fire, and toxic gases from spreading between adjacent rooms and floors for the rated time period. The following charts give the number of 3M pillows needed to completely firestop an opening that cable tray passes through. * Two (2) sticks of. STOPS SHALL BE FIRE PROOFED AS REQUIRED BY APPLI ABLE CODES.