BS ISO 2403:2021 pdf download – Textiles — Cotton fibres — Determination of micronaire value This document specifies a method of determining the micronaire value of loose disorientated cotton fibres taken from bales, laps and slivers, or other sources of lint cotton. 2  Normative references 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. ISO 139, Textiles — Standard atmospheres for conditioning and testing ISO 1130, Textile fibres — Some methods of sampling for testing 3  Terms and definitions For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https://www.iso.org/obp — IEC Electropedia: available at https://www.electropedia.org/ 3.1 micronaire value measure for the air permeability of a mass of cotton under specified conditions Note 1 to entry: The micronaire scale is based on a range of cottons to which micronaire values have been assigned by international agreement. Note 2 to entry: It is expressed in terms of an arbitrary scale, the so-called micronaire scale. 4  Principle Air is passed through a test specimen consisting of a plug of fibres. The permeability is indicated on a scale for recording variations in either the rate of flow through, or the pressure difference across, the plug. The mass and volume of the test specimen are either a constant for a given type of instrument or varied appropriately in relation to each other. The scale indicating variations in permeability can be calibrated in arbitrary units of micronaire value or marked in the appropriate absolute units of rate of flow or of pressure difference and a table or graph provided for conversion of the observed readings into micronaire values. 5  Apparatus and materials 5.1  Balance, of sufficient capacity to weigh the test specimen required for the airflow instrument used, with an accuracy of ±0,2 %. to be tested to determine whether or not the instrument is correctly adjusted and is giving results on the correct level (for more information, see Annex A). 8.1.1  Consider the performance of any instrument to be within the requirements of this document if the average results for each such calibration cotton do not differ from its corresponding established values by more than ±0,10...

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