BS EN ISO 536:2020 pdf free.Paper and board一Determination of grammage.
BS EN ISO 536 The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. For the determination of conditioned grammage, prepare and weigh the test pieces in the same atmospheric conditions as used to condition the specimens. For the determination of conditioned grammage and oven dry (see A.1) grammage, using the cutting device (5.1), cut test pieces from conditioned specimens. If possible, cut at least 20 test pieces from at least five specimens, taking the same number from each specimen. For the determination of“as-taken” grammage, follow the same procedure, minimising the influence of the ambient atmosphere on the moisture content of the test pieces (see A.2).Whenever possible, each test piece shall have an area of not less than 50 000 mm2 (preferably 200 mm x 250 mm) and not more than 100 000 mm2. If necessary, it may be composed of several smaller pieces. In cases where there is only a limited sample area available and it is not possible to make up a test piece comprising several smaller pieces, a test area of not less than 10 000 mm2 (100 cm2) may be used. This  shall be reported as a deviation from the preferred range of 50 000 mm2 to 100 000 mm2 specified in this document.If the variation in area of test pieces of the type of paper or board being tested exceeds the limits specified in 5.1, at the moisture content at which the grammage is determined, or if it is unknown,determine the dimensions of each test piece to the nearest 0,5 mm and calculate the area of each.Weigh each test piece on the balance (5.2) and express its mass, or indicated grammage if a special sheet-weighing balance is used (5.3), to three significant figures.It is recommended, especially when dealing with small pieces, that contact of the test piece with bare hands be avoided.
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