Specified Technologies Composite Sheet 16 x 28 in.

Reference#: 73333
Item#: CS1628


STI Firestop Composite Sheet

Lightweight, easily fabricated panels surface mount to walls and floors to provide a neat, clean firestop seal for medium to large openings with a variety of penetrants in fire-rated floors and walls.

SpecSeal® Composite Sheet is a lightweight, rigid fire resistant panel consisting of an intumescent layer bonded to a galvanized steel sheet reinforced with steel wire mesh covered with aluminum foil. SpecSeal Composite Sheet is designed to seal medium to large size openings with a variety of different penetrants in both fire resistance rated floors and walls.

When exposed to temperatures in excess of 350°F (177°C), SpecSeal® Composite Sheet expands up to 15 times to form a dense insulative char that minimizes heat transfer.


  • Lighter and thinner – approximately 1/2 the weight and thickness of traditional composite sheet
  • Easier to fabricate – engineered with the installer in mind
  • Can be cut and installed with common sheet metal tools
  • Intumescent – expands up to 15 times when exposed to temperatures in excess of 350°F (177°C) compared to 8-10 times for competing brands. Forms a dense insulative char that minimizes heat transfer
  • Hole reduction – reduces large openings when used in conjunction with other SpecSeal® or EZ-Path® Firestop Products
  • Acoustically tested – reduces sound transmission

    Common Applications:
  • Medium to large openings through common constructions
  • Single or multiple cable trays for power, voice, data
  • Multiple metallic conduits & tubing
  • Multiple mixed penetrants of many types
  • Suitable for clean room/area environment
  • Combine with the EZ-PATH® System for cable penetrations through large openings
  • Insulated metallic pipes
  • Blank openings
  • Plastic pipes
  • Metal pipes
  • Bus ducts
  • Specification

    Color: Pale Red
    Flame Spread: 0*
    Smoke Developed: 5*
    Odor: No perceptible odor
    Density (as shipped): Bulk approx. .45 – .55
    Density Mixed (wet) : .80g/L ± .03 (6.4 – 6.9 lb./gal.)
    Density (dry mortar) : .65 g/L (5.4 lb./gal., 40.5 lb./cu. ft.)
    Ratio Water/Mortar: 14.3/22 to 17.6/22
    Yield (per 22 lb.): 1,250 – 1,425 cu. in. (20.5 - 23.4 L)
    Shelf Life: No Limit
    Application Temperature: 35°F – 100°F (2°C - 38°C)
    Open Time: 30 Minutes working time