Paper Supply Contract Pulp Index Pass through Clause Mechanics
Paper contract pass-through clauses must weight indices to exact furnish shares and apply deadbands to prevent unearned mill margin inflation.
Air Dry Metric Tonne
Moisture Accounting
Pulp commerce relies upon an air dry metric tonne to establish a standardized mass for cellulose fibres containing a baseline moisture content of ten percent. Commercial pulp bales absorb ambient water vapour from warehouse atmospheres, meaning physical scales capture varying weights that do not reflect true fibre content. Mill contracts apply this calculation method to deduct excess water weight before invoicing buyers for the solid cellulose mass.
Drying Mechanics
Flash dryers and fourdrinier cylinders evaporate water until the remaining moisture fraction equals exactly ten percent relative to the total fiber mass. Industrial drying lines monitor output humidity through inline sensors because under dried pulp inflates transportation costs with dead water weight while over dried stock damages fibre length during subsequent refining. Buyers verify delivered shipments by drawing core samples from multiple bales, drying those specimens in laboratory ovens, and comparing bone dry weights against commercial billing masses.
Billing Tolerance
Commercial contracts specify allowable moisture deviations around the standard baseline, and financial penalties apply when delivered shipments exceed the agreed water threshold. Paper mills factor this mass adjustment into pulp storage calculations and chemical dosing ratios because excess moisture alters stock consistency inside hydropulpers. Accurate fibre accounting prevents financial disputes between international pulp producers and downstream paper manufacturers during large scale commodity trading.