My wife made furniture shopping a family event last weekend, which meant I had to go. The showroom was in a concrete tilt-up with open-web steel joists and a wood roof. My oldest son asked me who decides what construction materials are used, and why. He’s starting college in the fall and thinks he wants to be a mechanical engineer, but his curiosity about construction gives me hope that we can convert him.
Great question, though. We had a nice discussion about some of the advantages of certain building materials for different applications. Very often, the materials decision is driven not by structural properties, but rather by code fire requirements, which are usually determined by the architect on a project. As structural engineers, we must incorporate those fire requirements into our design. Sometimes this is simple — we need the wall on the property line to be concrete or masonry, for example. Other details can be more challenging, such as allowing for two layers of drywall on wood-framed, load-bearing walls.
We first introduced the DG fire wall hanger series in 2017. There are three models of top-flange hangers in this series. They feature enough space for two layers of ⅝” gypsum board to be installed after the framing is complete. The hangers are approved to the 2012, 2015 and 2018 I-Codes® and listed under ICC-ES ESR 2553.
All three fire wall hangers have been tested according to ASTM E814 and received F (flame) and T (temperature) ratings for use on one or both sides of the wall. These ratings verify that the DG/DGH/DGB hangers do not reduce the two-hour fire wall assembly rating.
You may recall reading about the DG hangers on the SE blog last year. I discussed the use of fire wall hangers in Why Fire-Rated Hangers Are Required in Type III Wood-Frame Buildings, and these hangers specifically in What You Should Know About the New DGH Fire Wall Hanger Options.
If you are an engineer, builder or code official interested in learning more about how these DG hangers can be used in light-frame wood multi-story residential buildings, I encourage you to attend a free webinar, “Making Wood Connections Work for Two-Hour Fire Walls,” on Wednesday, July 25, at 11 a.m. PDT. Project manager Tom Evans and I will provide an overview of how these hangers were developed, how they were tested and verified, and what F (flame) and T (temperature) ratings mean.