STI SpecSeal® Triple S® Intumescent Sealant Tube

The Most Versatile 2-Stage Latex Intumescent Sealant

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What's special about firestop sealant?

  • Two-stage intumescence process is extremely fast acting and effective, providing an excellent smoke seal
  • UL ratedAdheres 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
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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.


STI-SSS100 STI SpecSeal Triple S Intumescent Premium Grade Sealant 10.1 oz orange 0.90 lbs
  • 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
  • Made in the USA



  • 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:


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






Abesco CP310 Fire Rated Acrylic Intumescent CaulkAbesco CP310 Fire Rated Acrylic Intumescent Caulk
Designed to seal and prevent the spread of fire from one compartment to another wherever cables, wires, or other services pass thru firewalls and/or floors.

Fire Caulk 3M? Fire Barrier 2000 Silicone Sealant3M™ Fire Barrier 2000 Silicone Sealant
Ideal for sealing simple penetrations such as around metallic or glass pipes and conduits to control the spread of fire. Helps limit the spread of noxious gas, smoke and water. Maintains the integrity of fire-rated construction.


This gun facilitates the use of caulking around the home or workspace and simplifies application of sealants, glues, caulks, and other tube cartridges.

firestop sleeveSTI Split Firestop Sleeve Kits
Ready™ Split Sleeves are designed with a split pathway and come with wall plates which allow them to be implemented around existing cable bundles. These sleeves weigh half of what competing threaded products do, and have fewer parts, which make them the product you need when you are working on ladders or in cramped spaces in rated and non-rated construction zones.


firestop putty, SP100STI SpecSeal SSP Putty
An excellent product for retrofit jobs and cabling that call for a firestopping sealant. It is easy to apply and meets the highest quality standards. This 36 cubic inch bar is all you need for metallic conduits, telephone, data or electrical power cable penetrations as well as a variety of sleeved and non-sleeved applications.

latex fire sealantNelson Firestop LBS3™ Latex Sealant
Nelson Firestop Sealant (LBS3™) is ideally suited for for firestopping through-penetrationsof non-combustible pipe, insulated pipe and combustible pipe (such as PVC, PEX, CPVC and ABS) in floors or walls. It can applied using a standard caulk gun, bulk loader, or trowel. If you are working with a large area, it can be pumped directly from the pail.

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