Solid Wood Products 2557 



Table 22-1 — Input of woody furnish required to yield a ton (ovendry basis) of product 



(Koch 1976a) 



Form of Input of 

 Commodity woody furnish woody furnish 



Tons, ovendry 

 Insulation board 50-50 mix of bark-free and barky chips of 



mixed species 0.96 



Underlayment particleboard Planer shavings, sawdust, and plywood 



trim 1.02 



Wet-formed hardboard 50-50 mix of bark-free and barky chips of 



mixed species 1.15 



Medium-density fiberboard 50-50 mix of bark-free chips and barky 



roundwood of mixed species 1.16 



Structural flakeboard and pallet Mixed-species barky logs 1.24 



lumber 



Lumber laminated from veneer .... Barky logs 2.13 



Softwood sheathing plywood Barky logs 2.22 



Softwood lumber Barky logs 2.86 



Hardwood plywood paneling Barky logs 3.33 



Oak flooring Barky logs 3.57 



In computing energy credits for manufacturing residuals (e.g. , green bark and 

 sawdust), it is assumed that exhaust steam from turbines or steam engines will be 

 used for process steam. Thus, a non-condensing turbine connected to an AC 

 generator should consume about 16.3 pounds of high-pressure steam to deliver 

 one brake horsepower-hour of mechanical work. The 16.3 pounds of spent 

 steam at low pressure is then available for process heat. It has additionally been 

 assumed that 1 pound of green bark (half water by weight) will generate about 

 2.6 pounds of high-pressure steam. 



Production of hardwood flooring, softwood lumber, or decorative hardwood 

 plywood — including logging and transport to construction site — calls for net 

 expenditure of about 3 million Btu of oil equivalent per ton (ovendry basis) of 

 product if mill residuals are credited against energy demand of the milling 

 process. Reconstituted boards, i.e, fiberboards and particleboards, require S'/z 

 to 21 million Btu per ton produced (table 22-2). 



ENERGY REQUIREMENTS FOR NONWOOD-BASED 

 COMMODITIES 



Production of structural commodities from nonrenewable resources and trans- 

 port to building site requires net energy inputs ranging from less than 4 to as 

 much as 200 million Btu oil equivalent per ton (table 22-2). 



