This method describes a procedure for measuring the internal fiber bond strength (z-direction tensile strength) of paperboard using an instrument that subjects a normal separation force to a 6.45-cm (1-in. ) specimen. 2 2 The procedure consists of applying double (two-sided) coated, pressure-sensitive tape to both sides of a test specimen. The specimen is then placed between two platens and compressed uniformly over the entire specimen surface area. Uniform tension is then applied over the entire test area in a direction perpendicular to the plane of the sample (z-direction) to affect a separation. The test is intended for paperboards and some papers (see 9.4) which have an internal fiber bond strength (cohesive strength) lower than the adhesive bond strength of the tape to the specimen and/or test platens.