CORESTA Recommended Method No. 77
In 2010, the Physical Test Methods Sub-Group of CORESTA launched the Diffusivity Working Group with the objective to develop a CORESTA Recommended Method (CRM) for the “Determination of Diffusion Capacity by Measurement of CO2 Transfer Rate Through Materials Used as Cigarette Papers and Cigarette Papers having an Oriented Zone of Reduced Diffusion Capacity”. During eight meetings from January 2010 until September 2012 the Working Group developed a draft of the method. In the Working Group it was decided to have a method available which covers all instruments commercially available at that time. In January 2012 a test for the robustness of the method was conducted, involving current commercially available types of diffusion capacity measurement instruments and a broad selection of conventional and lower ignition propensity cigarette papers from various paper suppliers. Over five days the influence of laboratory conditions, conditioning of the paper, and instrument set-up and configuration, such as head size and differential pressure, on the measured diffusion capacity was checked. These results were discussed within the Working Group and were used to identify and define important parameters for the diffusion capacity measurement in the draft of the CRM. In 2013 a first inter-laboratory study for the determination of repeatability and reproducibility according ISO 5725-2:1994 involving 15 laboratories and five paper samples was conducted. After adding these results to the final draft of the CRM, the drafted CRM was approved by the Scientific Commission and the Board of CORESTA and was published as CRM No. 77 in April 2014.