Static Compression Thresholds for Double Wall Corrugated Boxes under Moisture
Double wall static compression thresholds drop 40 to 60 percent above 80 percent humidity, requiring safety factor adjustments to prevent warehouse collapse.
TAPPI T 804
Testing Standard
Standardized laboratory evaluation procedures define the methods for measuring the resistance of fiberboard shipping containers to compressive forces. Packaging laboratories apply TAPPI T 804 to determine the peak load a box can withstand before it collapses. This protocol provides a reliable measure of potential warehouse stacking performance.
It helps manufacturers design boxes that survive long storage.
Compression Process
Compressive force is applied to the carton between two flat, parallel platens that move together at a constant speed. Under the TAPPI T 804 method, the box is pre-conditioned to standard temperature and humidity to ensure that the test results are repeatable. This controlled environment is necessary because moisture content affects the strength of the board.
It ensures that different labs get comparable results.
Quality Compliance
Compliance with this testing standard is required by major retail chains and shipping agencies to guarantee that incoming packaging can withstand the stresses of automated handling systems. The maximum force recorded during the test is compared against the calculated stack loads to determine the safety factor of the design. If a batch of cartons falls below the required threshold, the converter must adjust either the board weight or the fluting profile to improve the structural strength, which prevents product damage during distribution.