BS EN 4426:2020 pdf free.Aerospace series一Non-metallic materials一Textiles – Test method一Determination of conductivity and pH of aqueous extracts.
BS EN 4426 This document specifies the requirements for the determination of conductivity and pH of aqueous extracts of textile materials.This method has been written in response to an aerospace requirement for a method of extraction using hot water as the EN 1413 requires only a cold water extraction method.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.EN 1413, Textiles一Determination of pH of the aqueous extract 1) EN 4385, Aerospace series一Non-metallic materials – – General organisation of standardization一Links between types of standards 2) EN ISO 2231, Rubber一or plastics-coated fabrics一Standard atmospheres for conditioning and testing 3) IS0 383, Laboratory gassware – Interchangeable conical ground joints 3) 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 fllowing addresses:●ISO Online browsing platform: available at http://www.iso.org/obp●IEC Electropedia: available at http:/ /www.electropedia.org/3.1conductivity reciprocal of the resistance of an electric current to pass through an electrolyte; the purer the electrolyte the higher the electrical resistance, conversely the lower the conductivity.5 Principle/technique An aqueous extract is prepared using de-ionised (low conductivity) water. For conductivity the extract is
measured to determine the ease by which a small electric current can be passed through the extract. The higher the amount of impurities in the extract the higher the conductivity reading. For pH the number of free hydrogen ions are measured using a pH electrode. pH is measured on a scale of1 to 14, 1 being acidic, 7 neutral and 14 alkaline.6 Resources 6.1 Apparatus/facilities 6.1.1 Round bottomed flasks of chemically resistant glass with a volume of 250 ml and a ground glass neck of size 24/29 in accordance with ISO 383. 6.1.2 A glass stopper incorporating a stopcock with P.T.F.E core liner to prevent sticking of the glass core in the neck of the stopcock. NOTE Grease shall not be used for this purpose. 6.1.3 Water-cooled condensers.BS EN 4426 pdf download.