Thermal Insulation Block

A rigid item designed to provide low thermal conductivity. It is composed of one or more kinds of granules and/or fiber with binder added, and has no specific surface perforations, fissures, slots or the like. It is supplied in lengths up to and including 36 inches (914.4 mm). For longer items, see insulation board, thermal. Excludes building board (as modified); millboard, asbestos; asbestos sheet, compressed; cork sheet; cork and rubber sheet; and fiberboard (as modified). See also insulation blanket, thermal.