Background

The ubiquitous nature of paper and paper products belies the accurate and precise testing that must be conducted to ensure the suitability of paper for even routine applications. For more than 30 years, this interlaboratory testing program has helped laboratories continuously monitor their testing performance.

In 1969, the US National Bureau of Standards (now NIST) and the Technical Association of the Pulp and Paper Industry (TAPPI) developed an interlaboratory program for paper and paperboard testing. Since 1971, Collaborative Testing Services has operated the Interlaboratory Program for Paper and Paperboard with guidance from TAPPI. With hundreds of organizations from around the world participating in these tests, this program has become one of the largest of its kind. The program allows laboratories to compare the performance of their testing with that of other laboratories, and provides a realistic picture of the state of paper testing for TAPPI.

Analysis Techniques

For each testing cycle, program participants are sent two samples of similar composition for testing in their laboratory. The laboratory measures the indicated physical property using the corresponding TAPPI test method. Results from all participating laboratories are returned to CTS by a specified Data Due Date. CTS will analyze the data and issue reports summarizing individual and group performance. The analysis of the data is based on consensus statistics, comparing each laboratory's measurements to the Grand Mean for that property. In addition, the property measurements for both samples are analyzed together (bi-variate analysis) to evaluate the lab's ability to make consistent measurements. Finally, the results are shown on a two-sample plot with a control ellipse. This graphical representation is a powerful analysis tool describing the nature and magnitude of the difference between a laboratory's results and the consensus results. Samples are shipped 6 times a year, providing laboratories with an on-going quality assurance tool for the evaluation of performance. To make the continual assessment easier, CTS provides Trend Charts that summarize lab performance over a revolving year.

Test Areas

The Paper, Paperboard, & Fiberboard Program offered by CTS includes interlaboratory testing for many of the physical properties of concern to papermakers. The tests are divided into two categories - Strength tests and General tests. Strength tests include burst, tear, folding endurance, tensile, internal bond, and other strength properties. The General tests focus on sheet and surface properties such as color, thickness, air resistance, smoothness, brightness, gloss, etc. Laboratories may individualize their testing programs by subscribing to one or more tests from either of these two categories.

More Information

If you have questions regarding any aspect of CTS' Paper, Paperboard & Corrugated Fiberboard Interlaboratory Testing Program, please contact program staff.