Curtain Wall Insulation is not generic. Manufacturers use proprietary formulations, patented technology around fiber formation, fiber optimization and other product performance attributes when it comes to perimeter fire protection. Mineral wool insulation products that are suitable for thermal/acoustical applications may not be suitable for fire containment assemblies.
Check with mineral wool manufacturers to determine the correct insulation product that has been tested to ASTM E 2307.
Mineral wool spandrel insulation needs to be slightly oversized to fit within spandrel opening. There should be no gaps or spaces between framing and edges of curtain wall insulation. These gaps would allow for flame and hot gases to pass through any openings.
Typically vertical seams are not allowed without proper reinforcement member to support the seams.
Horizontal seams allowed, however, reference tested listed system for location and number of seams allowed.
Spandrel insulation typically foil faced on one side. Foil facing (FSK or FSP) provides a vapor barrier. Seams at spandrel insulation edges to be taped with aluminum foil tape to provide continuous vapor barrier. Reference tested/listed assemblies.
Spandrel Insulation installed flush with interior face of the framing.
Min. 1” air space required between spandrel insulation and glass.
Spandrel Insulation to be mineral wool, check UL or Intertek Listing for approved manufacturer.
UL systems will list spandrel insulation by product name, manufacturer and required thickness and nominal density.