Containerboard Program - Collaborative Testing Services, Inc. - Providing Worldwide Interlaboratory Testing Since 1971.

The strength and quality of corrugated containers is directly dependent upon the strength and quality of corrugated board and its component containerboard. A containerboard laboratory must produce accurate & precise results to make certain that the linerboard, medium, boxes and corrugated board meet or exceed quality specifications. The CTS Containerboard Program is a key component to ensure that your laboratory measures up to this goal.

To read the complete Story of how the Containerboard Program works, please view our How To Guide.

Test Areas

Each month, one weight of medium (26 lb.) is used to test Concora Flat Crush Strength, Fluted Edge Crush, Ring Crush, and STFI Compression. Two weights of linerboard are tested each month for Mullen Burst, Ring Crush, and STFI Compression. Standard 42 lb. linerboard is tested every month; 36 lb. and 69 lb. are tested in alternate months.
Roughness (Stylus Method), Internal Bond, Coefficient of Friction, and Air Resistance (Gurley) tests are offered once a month on 42 lb. linerboard. Edgewise Compressive Strength on corrugated board and Box Compression Strength tests are also offered once per month.

Samples and Analysis Techniques

The Containerboard Program is unique among CTS' Interlaboratory Programs as it was designed as a collaborative reference program (CRP). The linerboard and corrugating medium samples are randomized and placed in sealed packages for repeated distribution. The samples are taken from the same lot and sealed at one time allowing their use as collaborative reference material.

Samples of linerboard and corrugating medium are cut from uniform narrow rolls, randomized, and distributed either once a month or once every other month for weekly testing. Participants return their test results weekly for analysis and receive a monthly report. The Summary Report, which includes all data submitted by the due date and is available only on the CTS Web site, divides each analysis is divided into three time spans. The left side of the table displays the individual laboratory results for each week of the month; the center of the table each lab's statistical data for the month; and the right side fo the table lists each lab's cumulative data for up to 16 weeks. The bottom of the table shows the statistics for all the participants for each of the three time spans. All results are coded for confidentiality. In addition to the Summary Report, CTS prepares and mails to each participant an individualized Performance Analysis Report. These individual reports include laboratory results from the previous six months.

The Interlaboratory Program for Containerboard is operated and maintained by Collaborative Testing Services, Inc., (CTS), with technical guidance provided by the Containerboard Group of the American Forest & Paper Association (AF & PA)