TAPPI T 411 OM

Abstract

This method describes the procedure for measuring single-sheet thickness and variations in single sheet thickness of paper, paperboard, and combined board. The term "combined board" encompasses both corrugated and solid fiberboard. <br>Because of the method of selecting samples longer in the cross machine direction for thickness profile measurements, the results will always be biased in that direction. <br>Because of the relatively high pressure 50 kPa (7.3 psi) used in this test method, it may not be suitable for measurement of tissue or other soft or low density materials, because the structure may collapse (decrease in thickness) at the prescribed pressure of 50 kPa. <br>Another method for measuring the thickness of paper is TAPPI T 500 "Book Bulk and Bulking Number of Paper," which describes a procedure for measuring the overall thickness of a stack of book paper under pressure of 250 kPa (35 psi). <br>An essentially identical method is described in ASTM D 645-96. <br>TAPPI T 551 "Thickness of Paper and Paperboard (Soft Platen Method)" describes a method for measuring the effective thickness of paper and board products utilizing soft rubber platens. This method always yields smaller values than TAPPI T 411.