Rockwool Safe'N'Sound® Fire & Sound Insulation (Specific for 2" by 4" WOOD framed walls with joists spaced 16" apart) Dimensions: 3" x 15¼" Coverage: 59.7 sq. ft./bag Application: Walls (interior partitions), Floors, Ceilings Sound Class: 45 (when used with Type X drywall and resilient channel). Fire Resistance: 1 hr. (non-loadbearing), ¾ hr. (loadbearing). Rockwool Safe'N'Sound® is a stone wool insulation that offers superior fire resistance (melting point of 1177° C), sound absorption, and moisture resistance. As an alternative to fiberglass, this mineral wool insulation is easy to cut and fits into walls using friction. Data Sheet