Hygiene
Free swell is a datasheet number. Absorbency under load is the one the product is judged on, and it can be less than half.
— g
SAP at its loaded capacity plus the fluff
Capacity is not the same as acquisition — a core with capacity to spare still leaks if it cannot take the liquid fast enough, and gel blocking makes that worse as the SAP swells. Pair this with a strike-through and rewet assessment before signing off a construction.
Diaper Core SAP Swelling & Capacity Under Load Calculator — free, with the formula and a worked example, at Textile School.