Cavity fire stops are formed with 90mm Rockwool SP120 Firestop Cavity Slab systems in commercial and industrial structures. The solution is appropriate for varied cavity widths in masonry and curtain wall constructions and can be fitted horizontally or vertically. The SP Firestop Fixing Brackets are designed as a one-piece system that allows for easy cutting and use. It has a distinctive lateral compression that helps with fit tightness. A semi-rigid slab with a smoke-resistant aluminium foil facing on both sides makes up the product. The SP120 Slab has a two-hour fire resistant rating.