Flat crush hold serves to define the corrugated cardboard/fiberboard 's hold to compressive loads, the level of the Flat crush hold depends on the flute material and the type of the flute.
Walls simple retain the shape and do not influence the crush hold. Round samples, 90 mm in diameter, are cut out of the cardboard, and then crushed between two crushing plates.
The pressure necessary to deform The flute is then measured. The results are expressed in kPa.
The equivalent of The FCT has grown The test in The case of measuring The flute to hold to flat crush is CMT test.