ANSWER

From Table 508.4, Group A and Group R require a 1-hr separation when the building is equipped with sprinklers. You can use a 3.5” steel stud with one layer of 5/8” gyp board on each side. Find this in the UL Wall Selector.

From Table 508.4 Group I-3 and Group M require a 2-hour separation when there are no sprinklers. You can get the 2hour rating by using a 3-5/8” stud and adding another layer of 5/8” gyp to each side. For the STC you can choose a variety of methods, including air gaps, resilient channels or insulation.

On the ARE you will probably be asked to find the thinnest, or the cheapest wall. Lots of ways to build these things, but adding layers of 5/8” gyp is typically the fastest way to get to your rating.

Don’t try to memorize the contents of Table 508.4, but do try to memorize that your required separations are on Table 508.4, so you can quickly find it in the provided resources if needed.

1 HR RATED WALL

2 HR RATED WALL



WALL ASSEMBLIES FROM USG