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BRITISH STANDARD Surface active agents Ð Determination of stability in hard water The European Standard EN 12458:1999 has the status of a British Standard ICS 71.100.40 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BS EN 12458:1999 Confirmed June 2009 BS EN 12458:1999 National foreword This British Standard is the English language version of EN 12458:1999 The UK participation in its preparation was entrusted to Technical Committee CII/34, Methods of test for surface active agents, which has the responsibility to: Ð aid enquirers to understand the text; Ð present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; Ð monitor related international and European developments and promulgate them in the UK A list of organizations represented on this committee can be obtained on request to its secretary Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled ªInternational Standards Correspondence Indexº, or by using the ªFindº facility of the BSI Standards Electronic Catalogue A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application Compliance with a British Standard does not of itself confer immunity from legal obligations Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages to 5, and a back cover This British Standard, having been prepared under the direction of the Sector Committee for Materials and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 June 1999 BSI 06-1999 ISBN 580 32269 Amendments issued since publication Amd No Date Comments EN 12458 EUROPEAN STANDARD NORME EUROPÊENNE EUROPẰISCHE NORM February 1999 ICS 71.100.40 Descriptors: surfactants, tests, measurements, stability, water hardness English version Surface active agents Ð Determination of stability in hard water Agents de surface Ð DeÂtermination de la stabilite aÁ l'eau dure GrenzflaÈchenaktive Stoffe Ð Bestimmung der BestaÈndigkeit gegenuÈber hartem Wasser This European Standard was approved by CEN on 25 January 1999 CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom CEN European Committee for Standardization Comite EuropeÂen de Normalisation EuropaÈisches Komitee fuÈr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1999 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref No EN 12458:1999 E Page EN 12458:1999 Foreword This European Standard has been prepared by Technical Committee CEN/TC 276 ªSurface active agentsº, the Secretariat of which is held by AFNOR This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by August 1999, and conflicting national standards shall be withdrawn at the latest by August 1999 Annex A is informative Endorsement notice The text of the International Standard ISO 1063:1974 was approved by CEN/TC 276 as a European Standard with the following modifications as given below: a) change of units ªmeqº to ªmmol/lº; b) inclusion of an informative annex A; c) text editorially revised According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom BSI 06-1999 Page EN 12458:1999 Introduction Principle A knowledge of the stability of surface active agents in hard water is of great importance for all the applications of these substances, since the precipitates obtained with hard water can reduce their effectiveness in practice The tests specified in this document are carried out with an aqueous solution of calcium chloride of known hardness In certain cases, it can be necessary to use other ions that give rise to hardness in water (see test report) Mixing of a solution of the surface active agent in differing concentrations with hard water solutions of differing known calcium hardness After leaving the solutions to stand in specified conditions, observation of their appearance, i.e clearness, opalescence, cloudiness or precipitation Scope This European Standard specifies a method of assessing the stability in hard water of surface active agents which are readily soluble at ambient temperature or slightly higher temperatures This method is applicable to surface active agents soluble in water at 20 8C It can be extended to those which are soluble at approximately 50 8C Normative references This European Standard incorporates by dated or undated reference, provisions from other publications These normative references are cited at the appropriate places in the text and the publications are listed hereafter For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision For undated references the latest edition of the publication referred to applies EN 12829, Surface active agents Ð Preparation of water with known calcium hardness (ISO 2174:1990 modified) EN ISO 3696, Water for analytical laboratory use Ð Specification and test methods (ISO 3696:1987) ISO 835-2, Laboratory glassware Ð Graduated pipettes Ð Part 2: Pipettes for which no waiting time is specified Terms and definitions For the purposes of this standard, the following definitions apply 3.1 hardness of water the hardness of water is due to the presence of soluble alkaline earth compounds and especially of calcium salts; it is expressed in millimoles of calcium (ll) ions per litre 3.2 stability of a surface active agent in hard water the stability of a surface active agent in hard water is determined by the solubility of the compounds formed by ion exchange between the surface active agent and the calcium ions, or by modification or the colloidal state by ionic forces, salt effect, pH value, etc BSI 06-1999 Reagents All reagents shall be of recognized analytical quality and the water used shall comply to grade in accordance with EN ISO 3696 5.1 Hard water solutions, prepared according to EN 12829 Ð Solution S1, of calcium hardness mmol (= 120,24 mg) of calcium (ll) ions per litre; Ð Solution S2, of calcium hardness 4,5 mmol (= 180,36 mg) of calcium (ll) ions per litre; Ð Solution S3, of calcium hardness mmol (= 240,48 mg) of calcium (ll) ions per litre Apparatus Ordinary laboratory apparatus and glassware, together with the following 6.1 Fifteen test tubes, for example 30 mm in diameter and 200 mm long, graduated at 50 ml Experience has shown that flat-bottomed test tubes are preferable, as they make it easier to observe cloudiness or precipitates 6.2 Pipette, ml, graduated at every 0,05 ml, complying with ISO 835-2 6.3 Thermostatically controlled water bath, for measurements carried out above 20 8C Procedure 7.1 Preparation of test solution Prepare a stock solution of 50 g of the surface active agent in 000 ml of water at 20 8C If the products are not readily soluble at 20 8C, prepare the solution at 50 8C This temperature shall be stated in the test report 7.2 Determination Using the pipette (6.2), transfer 5,0 ml of the test solution (7.1) to one of the test tubes (6.1) and add the hard water solution S1, (5.1) to give a volume of 50 ml NOTE Formation of foam can be troublesome and should be avoided when mixing the test solution with the hard water solution To achieve this, close the test tube containing the mixture with the hand or a bung, turn it slowly upside down and bring it back slowly to the original position This operation shall take s; repeat it ten times Page EN 12458:1999 Leave the test tube to stand for more than h but less than h at (20 ± 2) 8C and examine at this temperature for precipitates, cloudiness or opalescence In the case of a solution which changes with time (soap solution for example), the age of solution to the nearest min, shall be stated in the test report If it appears that the solubility of the calcium salts increases with temperature, carry out the test at (50 ± 3) 8C and make the observation at this temperature Carry out the determination similarly with 2,5 ml, 1,2 ml, 0,6 ml and 0,3 ml of the test solution (7.1) Proceed similarly with identical volumes of the test solution (7.1) and with the hard water solutions S2 and S3 (5.1) 7.3 Scoring Allot to the result of each determination a score number in accordance with the numbering system in Table Table Ð Score number corresponding to the appearance of the liquid Appearance of the liquid Clear Opalescent Cloudy Slight precipitate Heavy precipitate Score number (unit value) In case of doubt between the score numbers (for example, cloudiness and slight precipitate), choose the less favourable score number A liquid which is not clear, but through which objects can be seen, is regarded as opalescent A liquid which is not clear, and through which objects cannot be seen, is regarded as cloudy NOTE Although solutions in hard water of certain commercial surface active agents containing insoluble inorganic products are perfectly transparent, small quantities of crystals can appear at the bottom of the test tube or on the surface of the liquid These crystals are entirely different from the colloidal precipitates arising from hardness of the water and it should be necessary to centrifuge the solution, before testing, until it is clear Expression of results 8.1 Mean stability In general, a surface active agent is given a single stability figure which represents the ªmean stabilityº Add the 15 unit values obtained as described in 7.3 to obtain the total value, and calculate the mean stability, as shown in Table Table Ð Mean stability Sum of the 15 unit values 15 19 38 57 75 to to to to 18 37 56 74 Mean stability ªoneº ªtwoº ªthreeº ªfourº ªfiveº 8.2 Differential stability In some cases, however, it can be useful to note the stability of a surface active agent in hard water in terms of water hardness For each of the three solutions S1, S2 and S3, and in increasing order of hardness, add the five unit values obtained and determine the partial stability for each solution as shown in Table Table Ð Differential stability Sum of the five unit values for each sample of hard water Partial stability or one =1 to 12 two =2 13 to 18 three =3 19 to 24 four =4 25 five =5 Three figures are thus obtained, expressing the stability for each of the three hardness, mmol/l, 4,5 mmol/l and mmol/l, and characterizing the ªdifferential stabilityº The latter is, for example, 111 for the worst stability and 555 for the best stability in hard water Test report The test report shall include the following information: a) all details required for complete identification of the sample; b) the reference to this European Standard; c) the temperature of measurement; d) mean stability at t 8C: one to five; e) differential stability at t 8C: 111 555; f) any operation not included in this European Standard, or regarded as optional, as well as any circumstances which may have influenced the results; g) the date of the test BSI 06-1999 Page EN 12458:1999 Annex A (informative) Units used to express water hardness Name of units Definition Symbol Conversion factors Ca2+ mmol/l CaO meq/l 8d CaCO3 mg/kga) 8e 8a 8f millimole per litre mmol of calcium ions (Ca2+) in l of water mmol/l 2,000 5,600 100 7,020 5,850 10,00 milliequivalent per litre 20,04 mg of calcium ions (Ca2+) in l of water meq/1 0,500 2,800 50 3,510 2,925 5,00 German degree of hardness 10 mg of calcium 8d oxide (CaO) in l of water 0,178 0,357 17,8 1,250 1,044 1,78 milligram per kilogram mg of calcium carbonate (CaCO3) in l of water mg/kga) 0,010 0,020 0,056 0,070 0,058 0,10 English degree of hardness grain of calcium carbonate (CaCO3) in gal (UK) of water 8e 0,142 0,285 0,798 14,3 0,829 1,43 American degree of hardness grain of calcium carbonate (CaCO3) in gal (US) of water 8a 0,171 0,342 0,958 17,1 1,200 French degree of hardness mol (= 100 g) of calcium carbonate (CaCO3) in 10 m3 of water 8f 0,100 0,200 0,560 10,0 0,702 0,585 a) The unit ªpart per millionº (ppm) is often used for mg/kg BSI 06-1999 1,71 BS EN 12458:1999 BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BSI Ð British Standards Institution BSI is the independent national body responsible for preparing British Standards It presents the UK view on standards in Europe and at the international level It is incorporated by Royal Charter Revisions British Standards are updated by amendment or revision Users of British Standards should make sure that they possess the latest amendments or editions It is the constant aim of BSI to improve the quality of our products and services We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover Tel: 020 8996 9000 Fax: 020 8996 7400 BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services Tel: 020 8996 9001 Fax: 020 8996 7001 In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless otherwise requested Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help to Exporters Service Various BSI electronic information services are also available which give details on all its products and services Contact the Information Centre Tel: 020 8996 7111 Fax: 020 8996 7048 Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards For details of these and other benefits contact Membership Administration Tel: 020 8996 7002 Fax: 020 8996 7001 Copyright Copyright subsists in all BSI publications BSI also holds the copyright, in the UK, of the publications of the international standardization bodies Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means ± electronic, photocopying, recording or otherwise ± without prior written permission from BSI This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained If permission is granted, the terms may include royalty payments or a licensing agreement Details and advice can be obtained from the Copyright Manager Tel: 020 8996 7070