Standard Mass
Commercial pulp valuation relies on standardized moisture conversions to reconcile wet mill output with international trade contracts. The air dry weight formula provides the mathematical framework for calculating the commercial weight of pulp lots from tested dry solids content. Standard air dry weight assumes a nominal moisture content of ten percent, corresponding to ninety percent absolute dry fibre.
This conversion establishes a uniform baseline for invoicing pulp shipments across varying atmospheric conditions.
Calculation Protocol
Laboratory testing determines the dry matter content of a representative sample by heating it to constant weight at elevated temperature. The air dry weight formula then scales this bone dry mass up by dividing the measured dry weight by zero point nine. When a sample yields eight hundred and fifty kilograms of absolute dry fibre, dividing that figure by zero point nine produces a commercial air dry weight of nine hundred and forty-four kilograms.
Moisture testing must occur immediately upon sampling to prevent ambient humidity absorption.
Contract Tolerance
Discrepancies between actual pulp weight and billed commercial weight trigger price adjustments when they exceed agreed contract limits. The air dry weight formula sets the financial reference point that prevents buyers from paying for excess water.
