Polybond Mineral Wool LRB mattress are recommended for use in the thermal insulation of large vessels, boilers, machinery, equipmentâs, ducts, flanges, valves and plates operation at high temperatures. These mattress are exclusively suited for wrapping curved surfaces or for cutting to fit over irregular shapes. Mineral Wool LRB mattress are user for both hot and cold insulation to conserve energy, maintain process temperature, provide protection from heat and reduce noise level. Mineral Wool LRB mattress are used for thermal insulation of large diameter pipe, tanks, boilers, ventilation ducts, Refinery Insulation, ovens, furnace and fire insulation of fire doors.