Fiberboards 



2741 



SPECIFIC GRAVITY 



1 •! -2 .3 



VENEER 



\- 



SOLID WOOD- 



1.0 



PLYWOOD 



WAFER - 

 BOARD 



STRANDBOARD 



INSULATIONBOARD 



FLAKE- 

 BOARD 



PARTICLE- 

 BOARD 



MDF-DRY 



MDF-WET 



HARDBOARD-DRY 



HARDBOARD-WET 



10 20 30 



I I 



I I 



I I 



-| INSULATIONBOARD |— 



40 



DENSITY (LBS./FT^) 



HARDBOARD- 



(AMER. HARDBD. ASSOC. DEFIN.) 



Figure 23-1. — Classification of reconstituted wood products by particle size and prod- 

 uct density. MDF means medium-density fiberboard. (Drawing from Suchsland and 

 Woodson 1985). 



23-2 THE INDUSTRY 



Insulation board manufacture began in the United States during World War I. 

 The first hardboard plant was built in 1926. Medium density fiberboard (MDF- 

 dry was developed in about 1 965 , and its manufacture expanded rapidly during 

 the 1970's. 



The fiberboard industry, with the possible exception of the MDF-dry compo- 

 nent, is mature, and its growth has slowed (figs. 29-11, 29-12B, and 29-13). 

 Southern hardwoods can be effectively used in fiberboards and the availability 

 of these woods has influenced, and will continue to influence, plant location. 

 Future growth is correlated with the housing market (figs. 23-3 and 29-4). 



INSULATION BOARD 



Insulation board is produced in 12 plants (table 23-1), 7 of which are in the 

 South; only 1 is in the West. In the southern plants, hardwood usage varies with 

 location and season; in plants designed to accept hardwoods, and in seasons 

 sufficiently dry to log hardwood bottoms, the furnish may contain up to 90 

 percent hardwood. Between 1972 and 1981 only one insulation board plant 

 opened; six plants shut down between 1960 and 1981. Annual capacity and 

 production are shown in figure 29- 1 1 . Insulation board products are classified as 



