We have an opening in a wall framed with 6" studs and 5/8" sheetrock on either side. The contractor has used the Hilti Fireblock to close this opening. They have installed the fireblocks with the 5"side passing through the cavity. Is this acceptable as Hilti spec says for Studs up to maximum 3-5/8" the fire block can be installed with the 5" side passing through and for studs larger, the fire blocks have to be installed with the 8" side passing through.
The fireblocks are set back 1-1/2" from the face of the drywall, is this acceptable.
Shruthi,
You need to follow the UL/cUL-listed system or engineering judgment's (EJ) specifications. If the system or EJ specifies that the blocks need to be installed 8" deep, then they have to be installed 8" deep to be aligned with the system. Installing the blocks at a 5" depth would be incorrect per the system/EJ, and it would cause concern from a firestop standpoint to have the stud cavity itself exposed. As such, the blocks need to be reinstalled to be aligned with the system/EJ.
If you have future questions on installation, feel free to email usfirestopeng@hilti.com, and we would be happy to get you in contact with your local Fire Protection Specialist, who specializes in firestop applications in your specific jurisdiction.
Thank you,
Jessica Starks
Senior Fire Protection Engineer