Fire resistant low density acoustic panel

An acoustic building panel comprising a body formed of a fibrous material comprising:

• a first major surface;
• a second major surface opposite the first major surface;
• a side surface extending between the first major surface and the second major surface, the side surface further comprising:
• a first side surface;
• a second side surface opposite the first side surface;
• a third side surface;
• and
• a fourth side surface opposite the third side surface;
• the first and second side surfaces intersecting the third and fourth side surfaces;
• wherein the body has a thickness as measured between the first and second major surfaces, a length as measured between the first and second side surface, and a width as measured between the third and fourth side surfaces wherein a first ratio of length to thickness is at least 40:1 and a second ratio of width to thickness is at least 40:1;
• wherein the body having a bulk density as measured between the first major surface, the second major surface, and the side surface, the bulk density ranging from about 76.9 kg/m3 to about 96.1 kg/m3.

A method of forming an acoustic building panel, the method comprising:

• a) creating a blend comprising a fibrous material and mixing the blend with pressurized air in a mixing apparatus, the blend being transported along a machine direction as it is mixed;
• b) depositing the blend onto a conveyor to form a continuous web having a first thickness;
• c) passing the continuous web between a compression element along the machine direction, the compression element compressing the continuous web to a second thickness that is less than the first thickness;
• wherein the fibrous material of the blend comprises at least 70 wt. % of polyester fiber based on the total weight of the fibrous material, and the continuous web having the second thickness has a bulk density ranging from about 76.9 kg/m3 to about 96.1 kg/m3.