Hello,
in attached UL, they mentioned in item 3B to apply sealant flush with both surfaces of wall.
the question is: in case we have wall with thickness higher than mentioned in UL (for example 12") so we must to apply system on the whole 12" of thickness or it is enough to apply system on 4-1/2" .
please clarify the meaning of (flush with both surfaces of wall) in this case (wall with 12" thickness).
Hello,
The base/minimum firestop components required for this application in a wall would be continuous piece of 4" of wool and two 1/2" layers of FSONE MAX.
For walls over 9" we can address your application through an Engineering Judgment which will be a custom detail showing your exact application with the firestop components required to maintain the stated ratings. For the 12" wall, we could do two 4" layers of wool with a 1/2" layer of FSONE MAX flush with both sides of the wall leaving a 3" air gap between the wool layers.
To officially submit for Engineering Judgment please go to www.hilti.com/ej
Regards,
Jaeger Cox Fire Protection Engineer