In a recent team meeting, I was reminded of the power of a particular UL System for edge-of-slab conditions with steel-framed exterior walls. 

In steel-framed exterior wall conditions with a cantilevered floor runner (sometimes referred to as platform-framing) positioned on the floor slab’s edge, a gap between the floor edge and exterior sheathing needs to be protected to meet the IBC’s criteria mandating perimeter fire containment systems tested to ASTM E2307. In such conditions, the traditional method was to fill the top of the floor runner with mineral wool safing insulation and apply the firestop spray atop the safing (See Figure 1). This application method is consistent with UL System No. CW-S-0003 for SpecSeal® Firestop Products and similar system designs for other manufacturers’ products. 

Figure 1

With our SpecSeal® TTG intumescent gaskets, this cumbersome application method is a thing of the past. Install TTG to the floor runner before placement, and you can achieve a fully compliant ASTM E2307 listed system. TTG provides a clean installation in a single step (See Figure 2). The basis for this design is UL System No. CW-S-0007, featuring TTG. 

To learn more about unlocking the power of our tested and listed systems for perimeter fire containment, contact one of our experienced curtain wall and façade specialists today.

Figure 2

This article, by James Stahl Jr., VP & General Manager, Engineering & Emerging Businesses, originally appeared in the Spring Wrap-Up 2024 edition of The Burn.