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Intumescent Fire Stop Manufacturing. Selling Internationally.

FB-725 Fire Stop Product

ALVA-TECH Fire Barrier FB-725 Composite Sheet is a rigid panel primarily composed of a 0.250″ thick elastomeric sheet bonded to a 28 gauge galvanized steel sheet on one side. The elastomeric sheet is reinforced with hexagonal shaped steel wire mesh and bonded with 0.003″ aluminum foil on the other side.

When exposed to temperatures in excess of 250°F the elastomeric fire resistive sheet begins a uni-directional volumetric expansion of 4-10 times its original size. The material forms a refractory char that retards heat transmission and tightly seals penetrations against flame spread, smoke and toxic fumes.


The FB-725 Composite Sheet is used to seal penetrations and restore the fire rating to floor/ceilings or walls in which an opening has been made. These openings may be required to allow the passage of such penetrating items as power and communication cables, conduits, pipes, cable trays and ducts through to adjacent compartments.

Physical Properties

Sheet Sizes:

  • 36″ x 41″
  • 36″ x 36″
  • 24″ x 36″
  • 16″ x 28″
  • 12″ x 24″
  • Custom Sizes

FB-725 Features

  • Intumescence activated at low temperatures
  • Heat transmission retarded by formation of expanded char
  • Penetration sealed tightly against flame spread
  • Easy to install – cut to size and shape with common trade tools
  • Thermally conductive
  • Self-supporting panel
  • No mixing or damming needed
  • Available in custom sizes


Galvanized Sheet Metal0.17″ + 0.002″ (28 gauge)
Fire Resistive Sheet0.298″ + 0.040″
Restraining Wire20 gauge
Aluminum Foil0.0030″
Complete Material0.320 + 0.040″


  • Factory Mutual: 2-hour rating
  • Underwriters Laboratories: F-rating (2-hour)
  • System #CBJ4016
  • T-Rating 3/4 and 2-hour

Testing completed in accordance with ASTM E814 / U.L. 1479 Standard Fire Method of Fire Tests of thorough penetration firestops.

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