The fibrous glass insulation covered by this specification is intended for thermal insulation, acoustic insulation, or both for use on bulkheads, overheads, ventilation ducting, machinery, equipment, and piping for Navy ships. The classifications and uses are as follows:

a. Type I (thermal), form 1 (board), facing A (unfaced) is used for thermal hull, compartment, and ventilation duct insulation.

b. Type I (thermal), form 2 (blanket with binder), facing A (unfaced) is used for thermal bulkhead, overhead, and ventilation duct insulation.

c. Type I (thermal), form 3 (blanket without binder) is used as thermal insulation of machinery and equipment, and as a component of removable pads for valves and flanges at operating temperatures up to 1,200 °F.

d. Type I (thermal), form 4 (preformed pipe) is used on piping as thermal insulation for operating temperatures up to 370 °F.

e. Type II (acoustic), form 1 (board), facing C (faced with perforated MIL-C-20079, type I, class 2 fibrous glass cloth) is used for reduction of sound in spaces, such as machinery spaces, where there is a high level of noise. Type II (acoustic), form 1 (board) is the replacement for the backing board used in the construction of MIL-A-23054 backing board (see 3.2.2.6.1.1 and table VIII).

f. Type II (acoustic), form 2 (blanket with binder) is used for acoustic bulkhead, overhead, and ventilation duct insulation.

g. Type II (acoustic), form 2 (blanket with binder), facing D (faced with ½-mil thick polyester film reinforced with fibrous glass yarns scrim conforming to MIL-Y-1140 in a four-yarns-per-inch by three-yarns-per-inch construction adhered to polyester film with a fire-retardant thermosetting adhesive conforming to the fire requirements of MIL-A-3316) is used for thermal ventilation duct insulation, acoustic ventilation duct lining, bulkhead insulation, and on the plane surfaces of machinery spaces, shops, or other spaces where the insulation may be exposed to oil, water, grease, dirt, or high levels of humidity.