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12458:1999
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
Surface active agents Ð
Determination of
stability in hard water
Confirmed June 2009
Trang 2This 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
ISBN 0 580 32269 6
BS EN 12458:1999
Amendments issued since publication
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 2 to 5, and a back cover
Trang 3European 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
NORME EUROPE Â ENNE
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
Trang 4Page 2
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
Trang 5Page 3
EN 12458:1999
Introduction
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)
1 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
2 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.
3 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
4 Principle
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
5 Reagents
All reagents shall be of recognized analytical quality and the water used shall comply to grade 3 in accordance with EN ISO 3696
5.1 Hard water solutions, prepared according
to EN 12829
Ð Solution S1, of calcium hardness 3 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 6 mmol (= 240,48 mg) of calcium (ll) ions per litre
6 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, 5 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
7 Procedure
7.1 Preparation of test solution
Prepare a stock solution of 50 g of the surface active agent in 1 000 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
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 1 s; repeat it ten times
Trang 6Page 4
EN 12458:1999
Leave the test tube to stand for more than 1 h but less
than 2 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 5 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 1
Table 1 Ð Score number corresponding to
the appearance of the liquid
Appearance of the liquid Score number
(unit value)
Slight precipitate 2
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
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.
8 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 2
Table 2 Ð Mean stability
Sum of the 15 unit values Mean stability
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, S2and 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 3
Table 3 Ð Differential stability
Sum of the five unit values for each sample of hard water
Partial stability
Three figures are thus obtained, expressing the stability for each of the three hardness, 3 mmol/l, 4,5 mmol/l and 6 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
9 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
Trang 7Page 5
EN 12458:1999
Annex A (informative)
Units used to express water hardness
Name of units Definition Symbol Conversion factors
mmol/l meq/l 8d mg/kga) 8e 8a 8f
millimole per litre 1 mmol of calcium ions
(Ca2+) in 1 l of water
mmol/l 1 2,000 5,600 100 7,020 5,850 0 10,00
milliequivalent
per litre
20,04 mg of calcium ions (Ca2+) in 1 l of water
meq/1 0,500 1 2,800 50 3,510 2,925 0 5,00
German degree
of hardness
10 mg of calcium oxide (CaO) in 1 l of water
8d 0,178 0,357 1 17,8 1,250 1,044 0 1,78
milligram per
kilogram
1 mg of calcium carbonate (CaCO3) in 1 l of water
mg/kga) 0,010 0,020 0,056 1 0,070 0,058 5 0,10
English degree
of hardness
1 grain of calcium carbonate (CaCO3) in
1 gal (UK) of water
8e 0,142 0,285 0,798 14,3 1 0,829 0 1,43
American degree
of hardness
1 grain of calcium carbonate (CaCO3) in
1 gal (US) of water
8a 0,171 0,342 0,958 17,1 1,200 1 1,71
French degree
of hardness
1 mol (= 100 g) of calcium carbonate (CaCO3) in
10 m3of water
8f 0,100 0,200 0,560 10,0 0,702 0,585 0 1
a) The unit ªpart per millionº (ppm) is often used for mg/kg.
Trang 8BS EN
12458:1999
BSI
389 Chiswick High Road
London
W4 4AL
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