Commercial Mass
A standardized quantitative mass expression measures the theoretical dry fibre output relative to initial wood input adjusted for standard equilibrium moisture content. In commercial pulp trading, air-dry pulp yield defines the weight of pulp containing ten percent moisture relative to the oven-dry weight of raw wood entering the digester. Mill accounting relies on this parameter to determine fiber loss across cooking and bleaching operations.
Processing losses reduce net tonnage, altering line efficiency calculations. Digester operations monitor raw chip weight against finished bale output to verify operational performance. Yield variations directly affect chemical recovery cycle loading and spent liquor solids concentration.
Processing Boundary
Chemical pulping operations establish upper limits on recovery through lignin removal efficiency. Softwood species typically yield between forty-two and forty-eight percent dry fiber. Hardwood pulps achieve slightly higher recovery rates.
Moisture Factor
Commercial transactions standardize pulp weight at ninety percent bone-dry fibre and ten percent water content. The metric known as air-dry pulp yield accounts for atmospheric moisture absorption during storage and transport. Bales weighed at mill gates undergo moisture testing to adjust gross mass to contract specifications.
Deviations from ten percent equilibrium require billing corrections across international supply chains. Standard testing protocol TAPPI T 210 defines the sampling procedure for invoicing adjustments.
