SpecSeal SSS Firestop Sealant by STI FirestopSpecSeal SSS Firestop Sealant by STI Firestop is a premium-grade, water-based intumescent firestop sealant that can be used for blank openings, busways, cables and cable trays, duct, wall heads, metal pipes, and plastic pipes.

United Tool and Fastener has partnered with STI Firestop to bring the construction industry the fire-prevention products and knowledge they need to complete a job and make it the safest site possible.

SpecSeal SSS Firestop Sealant by STI Firestop incorporates the STI Firestop two-stage intumescent technology, making it a great choice for any combustible or non-combustible penetrants. As little as a ½-inch applied depth of the SSS Sealant is required to provide up to a 4-hour fire-resistance rating when tested to ASTM E814/UL 1479.


  • Patented two-stage intumescent technology
  • Easily works into tight spaces between penetrants
  • Compatible with CPVC piping
  • Can be sanded and painted to match its surroundings
  • Used in more than 500 through-penetration UL tested systems.

Installation of SSS Intumescent Firestop Sealant by STI Firestop is fairly simple.

First, areas needing protection must be clean and free of oil, loose dirt, rust or scale. Allow product to dry for a minimum of 24 hours before exposure to moisture. Consult manufacturer’s drawing for system design requirements. Forming or packing materials are necessary as an integral part of various system designs.

Second, sealant may be installed by caulking using a standard caulking gun, from bulk containers using a bulk loading caulk gun, or by manually troweling using a mason’s trowel or putty knife.

Third, install sealant to the required depth. Work sealant into all areas, being careful to eliminate voids or seams. The surface of the sealant can be smoothed using a putty knife dipped in water. However, adding water to the sealant itself is not recommended.  Once dry, the sealant may be sanded and painted using most non-solvent-based paints.

To explore and learn how the SSS Intumescent Firestop Sealant by STI Firestop works, watch the video below.

To learn more or to buy the SSS Intumescent Firestop Sealant by STI Firestop, or other STI Firestop  products, contact a local UTF showroom in Houston at 713-692-2323; in San Antonio at 210-495-8665; or College Station at 979-731-8665.