This industry comprises establishments primarily engaged in manufacturing paperboard from pulp. These establishments may manufacture or purchase pulp. In addition, the establishments may also convert the paperboard they make. Cross-References. Establishments primarily engaged in-- ? Manufacturing pulp without manufacturing paperboard--are classified in Industry 322110, Pulp Mills; ? Converting paperboard without manufacturing paperboard--are classified in Industry Group 3222, Converted Paper Product Manufacturing; and ? Manufacturing insulation board and other reconstituted wood fiberboard--are classified in U.S. Industry 321219, Reconstituted Wood Product Manufacturing.