15 C.F.R. § 1500.15
Masonry unit.
Masonry unit means a noncombustible building product intended to be laid by hand or joined using mortar, grout, surface bonding, post-tensioning or some combination of these methods.
Masonry unit means a noncombustible building product intended to be laid by hand or joined using mortar, grout, surface bonding, post-tensioning or some combination of these methods.