Hacker Industries announced an increase from 66 to 82 Underwriters Laboratories listings for its line of floor underlayments sold under the brand names of FIRM-FILL Gypsum Concretes and GYP-SPAN Radiant. The listings detail floor ceiling assemblies using a Hacker floor underlayment as an integral component to achieve a 1, 2, 3 or 4-hour fire rating.