Cable tray protection system

A fire protection system for installation about the periphery of a cable tray consisting of parallel side rails and spaced cross members fitted between the side rails, said fire protection system comprising component members formed from flexible, heat expanding, fire retardant composite sheet material having laminated on one major surface thereof a metal base layer, a wire netting laminated to the other major surface and an aluminum foil layer overlying said wire netting, said component members including a flat bottom portion, upraised longitudinally extending side portions, flanges extending laterally outwardly and parallel to said flat bottom portion along the longitudinal edge of each said side portion, a flat top member comprising a sheet of said fire retardant composite sheet material overlying said cable tray and juxtaposed and supported along its longitudinal edges by said laterally outwardly extending flanges of said side portions, elongated C-channel joining members fabricated from said fire retardant composite sheet material, coextensive with said laterally outwardly extending flanges, frictionally receiving and retaining within the throat thereof the juxtaposed longitudinal edge portion of said flat top member and each said laterally outwardly extending flange, and fastening means securing each said C-channel joining member and said juxtaposed longitudinal edge portion of said flat top member and said laterally outwardly extending flange together, said fire protection system being substantially noninsulating under ordinary ambient temperature conditions but becoming thermally insulating upon exposure to heat or flame.