Issue link: http://cp.revolio.com/i/808614
your functional spec. If we must choose to focus on the properties of the board instead of the container, ECT is a reasonable place to start. In fact, the addition of ECT (replacing burst) to the structure of the BMCs was really the first movement toward performance based packaging, the first attempt to connect a property of the material to the functional specification of "ability to carry load in a warehouse situation." But the ECT of a sample of combined board or even of the box itself is still well removed from container performance. A B-flute box and a C-flute box may well have the same ECT values, but can have very different box performance. As well, as a property of the material alone, ECT does not take into account issues of box construction that can dramatically impact carrying capacity of the container. 2 Paper Specifications One can also specify boxes by requiring specific weights of paper, by "recipe." This approach is a hold-over from a time 30 years ago and more when there were many fewer grades of paper and types of corrugated board. In that era, board optimization was less important and extra costs were either not recognized as such or were accepted as a part of getting a box that worked well. This approach can be taken today as well, but all papers are not the same even if they have the same weight. Paper properties depend on the fiber type and quality, and different areas of the globe use different kinds of fiber. Even when the fiber type is reasonably uniform across the market, for instance here in North America, the amount of recycled fiber in the mix can have an impact on strength. The impact of fiber type and history on paper properties means that even within a single market there can be a wide range of paper strength for the same nominal weight or marketing grade. Paper is not a commodity, and each paper mill produces a product with a specific range of strength, density, porosity, and robustness. In the US alone, the grade category of 35 high ring or high performance liner has a range in strength of about 20% depending on the mill and fiber source. On top of that, even if the papers all start with the same strength, the technical literature indicates that boxes made primarily with recycled papers have a shorter life time in the field. 3,4,5 In other words, under load these boxes tend to collapse sooner even though the papers may be the same grades and the boxes themselves start out with the same strength. Additionally, every boxplant may have slightly different combining equipment, corrugating roll profiles (even for "C Flute," which is just a generic term covering a range of profiles 6 ), and converting equipment. These types of differences mean that even if boxes are made with the same nominal grade of paper, we do not necessarily get the same performance. 15 ista views • April 2017 • www.ista.org > MORE ON PAGE 16