Ceiling Hangers shall be fail-safe and consist of opposed washers sandwiching an AASHTO Bridge Bearing Quality LDS Rubber Element 11/8” thick. Dynamic Stiffness shall not exceed 1.4” nor the corrected frequency 12 Hz. Connections shall be made with 12 gauge wire top and bottom passing through hairpin loops attached to the opposing washers. Ceiling Hangers shall be Mason Industries type WHR. Submittals shall confirm AASHTO Quality and Dynamic Stiffness in addition to frequency.