Fire Blocking Insulation

Fire block and firestop are two different concepts and use different materials.
Fire blocking insulation. Rockwool comfortboard 80 is a rigid mineral wool insulation sheathing board that is non combustible water repellent fire resistant and sound absorbent. Smoke and gases readily travel horizontally as well so preventing horizontal air movement such as within a dropped ceiling has its own name. Unfaced fiberglass batt insulation used as fireblocking shall fill the entire cross section of the wall cavity to a minimum height of 16 inches 406 mm measured vertically. F ire blocking aims to prevent or at least slow the vertical movement of flames smoke and gases by sealing off concealed spaces like stud cavities and soffits.
When piping conduit or similar obstructions are encountered the insulation shall be packed tightly around the obstruction. Owens corning 15 in.