This method determines the coefficient of static friction of most packaging materials by measuring the angle at which one test surface begins to slide against another inclined surface as the incline is increased at a constant and prescribed rate.

The test is frequently referred to as slide angle. The coefficient of friction is numerically equivalent to the tangent of that angle.

A method for determining the coefficient on a horizontal plane for corrugated and solid fiberboard is described in TAPPI T 816 "Coefficient of Static Friction of Corrugated and Solid Fiberboard (Horizontal Plane Method)." Both methods give results essentially equivalent to this method. TAPPI T 548 and TAPPI T 549 describe nearly identical methods for determining the coefficient of static friction but are intended for application to printing and writing papers and the procedures are somewhat different.