This specification covers glass fiber unsupported needled felt binder-free thermal insulations. This material is used as the thermal insulation component in the fabrication of insulation systems for use on machinery and equipment, such as steam turbines, boilers, boiler feed pumps, and piping at specified elevated temperatures. Thermal insulations should adhere to the following physical requirements: apparent thermal conductivity, hot surface performance, tensile strength, non-combustibility, and dimensions (nominal thickness, mass per unit area, length, and width).