2556 Chapter 22 



Yields of solid wood products are given in chapter 12, in section 18-12 (see 

 figs. 18-126 through 18-129), and in chapter 27. Chapter 27 also contains 

 conversion factors useful in yield studies of solid wood products. For page 

 references, see the index heading Yields and measures, products. 



The balance of the present chapter discusses classes of solid wood products, 

 including, where appropriate, manufacturing procedures and references to prod- 

 uct standards. These are preceded by comparisons of wood construction materi- 

 als with nonwood commodities in terms of energy, manpower, and capital 

 inputs. Most of the products described are important in commercial production, 

 but some have been made only on a laboratory or pilot-plant scale. 



22-1 STRUCTURAL COMMODITIES— WOOD AND 

 NONWOOD' 



Wood as a structural material competes with aluminum, concrete, steel, 

 brick, and petrochemical derivatives. Within the wood sector, solid wood prod- 

 ucts of both hardwood and softwood may compete with reconstituted products. 



On an ovendry basis, structural wood commodities require from 1 to 3'/2 tons 

 of woody furnish per ton of commodity manufactured (table 22- 1 ); reconstituted 

 boards have highest product yield, and lumber the lowest. Veneer products are 

 intermediate. 



ENERGY REQUIREMENTS FOR WOOD-BASED COMMODITIES 



Energy expended during harvesting and manufacture is comprised of three 

 major components: 



• Diesel fuel and gasoline for forest activities and logging 



• Mechanical energy (horsepower-hours) expended in the mill 



• Process heat consumed in the mill 



Additionally, energy is consumed in manufacture of resin and wax additives to 

 reconstituted commodities. Also diesel fuel and gasoline are consumed deliver- 

 ing the commodities to the construction site. 



To achieve a uniform mode of expressing energy consumed and available 

 from residues, the unit million Btu thermal (oil) has been used. For example, a 

 gallon of diesel fuel contains 138,336 Btu or 0.138 million Btu thermal (oil). A 

 mechanical horsepower-hour was assumed equivalent to 7,825/10^ million Btu 

 thermal (oil); this equivalency is based on the assumption that oil can be convert- 

 ed to mechanical power with about 32.5 percent efficiency. A pound of process 

 steam was assumed to contain 1,200 Btu which, if generated with an oil-fired 

 boiler at 82.5 percent efficiency, would require about 1,455/10^ million Btu 

 thermal (oil). 



•'Text under this heading is condensed from Boyd et al. (1977) and Koch (1976a), both based on 

 Boyd et al. (1976). 



