Abstract: A cooling tower with a plurality of fill packs has a fire stop with openings disposed below the fill packs, a water distribution system for distributing water onto the fill packs, and a cold water basin disposed below the fire stop for collecting water which has past through said fill packs. The openings in the fire stop occupy at least 80% of the area over which the fire stop extends. The fire stop is made of an intumescent material with an expansion ratio sufficient to close said openings when said material intumesces.

Abstract: A composition for a firestop is provided. The composition comprises a thermoplastic; expandable graphite; alumina trihydrate; and a flame retardant compound or mixture comprising antimony and a halogen. There is also provided a flame retardant composite, which comprises expandable graphite; alumina trihydrate; antimony; and a halogen. The halogen may include bromine. The flame retardant compound may be brominated antimony. The flame retardant mixture may include an antimony oxide and a compound containing bromine. The flame retardant composite may comprise brominated antimony, or comprise antimony trioxide and a bromine-containing compound.