STI SpecSeal® Triple S® Intumescent Sealant Tube

The Most Versatile 2-Stage Latex Intumescent Sealant


What's special about firestop sealant?

  • Two-stage intumescence process is extremely fast acting and effective, providing an excellent smoke seal.
  • Adheres to all common construction surfaces, which means that you can carry just one fire retardant sealant to many jobs.
  • Thanks to its water-insoluble active ingredients, the sealant will not re-emulsify once dry - moisture won't damage your work.
  • Click for More Features
  • UL

If you need one firestop product that can handle a wide variety of applications, the SSS line of sealants is the right choice for you. This multi-viscosity product offers exceptional shear-thinning qualities, which allow for quick and easy caulking. This sealant is ideal for construction gaps and blank openings in walls or floors. Tested and approved for use with metallic penetrants up to 30", SSS can be safely combined with other SpecSeal products.

Part # Description Size Color Weight Price
STI-SSS100 STI SpecSeal Triple S Intumescent Premium Grade Sealant 10.1 oz orange 0.90 lb
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  • Water-based compound is easy to clean, use for installs and dispose of.
  • Two-stage intumescence technology is able to quickly expand in all directions.
  • Safe because it has low VOC's and contains no solvents or halogens.
  • Acoustically tested for superior sound-proofing capabilities
  • Its innovative, low-shrinkage composition is safe on plastics, does not contain PCB's or asbestos, and remains flexible even when dry to allow normal pipe movement.
  • Once dry, you can sand and paint the sealant to match the environment.
  • Provides up to a 4 hour rating when tested to the rigorous requirements of UL 1479 (ASTM E 814); UL 2079 and FM approved.
  • The red color allows you to quickly identify any missed areas and easily inspect the work.
  • Excellent seal for safety from not just fire and gasses, but smoke as well.
  • Warranted against defects by STI
  • Proudly made in the USA US flag


  • Small to medium opening in all common construction
  • Medium to large openings in concrete floors and walls
  • Medium to large openings in gypsum walls
  • Pipes (steel, iron, copper, metallic, plastic, PVC, CPVC, PVDF, PEX, PEX-AL-PEX, ABS, PB)
  • Cable, cable trays, and bus duct
  • HVAC ductwork
  • Insulated pipes
  • Complete wood floor fire stopping package for electrical, plumbing, HVAC, TV and telephone
  • Plumbing
  • Mechanical
  • Electrical
  • Datacom
  • Combustible Penetrants
  • Noncombustible Penetrants
  • Construction Gaps

    Color Red   STC Rating
    (ASTM E90/ASTM C919) 62
    Odor Mild Latex VOC Content
    (EPA Method 24/ASTM D3960)
    0.18 lbs/ gal (22.0 g/L)
    Density 9.4 lbs/gal (1.13 kg/L) Shelf Rating 2 years
    Solids Content 80% ± 2% Expansion Begins 230°F (110°C) 1st Stage 350°F (177°C) 2nd Stage
    pH 8.3 Expansion Range 230°F to > 1,000°F (110°C to > 538°C)
    In Service Temperature 130°F (54°C) Volume Expansion > 500% Free Expansion
    Flame Spread 0*    
    Smoke Developed 10*    

    * Tested to ASTM E84 (UL723) at 14% surface coverage


    Certifications & Approvals:

  • California Dept. of Forestry & Fire Protection Approval - PDF PDF
  • California Evaluation Report - PDF PDF
  • City of New York Approval - PDF PDF

    Potential Health Effects:

  • Eye: Contact may cause irritation
  • Skin: Contact may cause irritation
  • Ingestion: Relatively non-toxic
  • Inhalation: Irritation of the nose, throat, and lungs may result from over-exposure to vapors or mist
  • Chronic (Cancer) information: Not classified as carcinogenic
  • Long Tem Toxic Effects: none known



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