SIST EN 901:2007
(Main)Chemicals used for treatment of water intended for human consumption - Sodium hypochlorite
Chemicals used for treatment of water intended for human consumption - Sodium hypochlorite
This European Standard is applicable to sodium hypochlorite used for treatment of water intended for human consumption. It describes the characteristics of sodium hypochlorite and specifies the requirements and the corresponding test methods for sodium hypochlorite. It gives information on its use in water treatment. It also determines the rules relating to safe handling and use of sodium hypochlorite (see Annex B).
NOTE While this standard is not applicable to sodium hypochlorite generated in-situ (see bibliographic reference [6]) the limits for impurities and chemical parameters apply.
Produkte zur Aufbereitung von Wasser für den menschlichen Gebrauch - Natriumhypochlorit
Diese Europäische Norm gilt für Natriumhypochlorit zur Aufbereitung von Wasser für den menschlichen
Gebrauch. Sie beschreibt die Eigenschaften von Natriumhypochlorit und legt die Anforderungen sowie die
entsprechenden Prüfverfahren für Natriumhypochlorit fest. Sie gibt Informationen für die Anwendung von
Natriumhypochlorit in der Wasseraufbereitung. Sie legt darüber hinaus Regeln für die sichere Handhabung
und Benutzung von Natriumhypochlorit fest (siehe Anhang B).
Produits chimiques utilisés pour le traitement de l'eau destinée a la consommation humaine - Hypochlorite de sodium
Kemikalije, ki se uporabljajo za pripravo pitne vode - Natrijev hipoklorit
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 901:2007
01-julij-2007
1DGRPHãþD
SIST EN 901:2000
Kemikalije, ki se uporabljajo za pripravo pitne vode - Natrijev hipoklorit
Chemicals used for treatment of water intended for human consumption - Sodium
hypochlorite
Produkte zur Aufbereitung von Wasser für den menschlichen Gebrauch -
Natriumhypochlorit
Produits chimiques utilisés pour le traitement de l'eau destinée a la consommation
humaine - Hypochlorite de sodium
Ta slovenski standard je istoveten z: EN 901:2007
ICS:
13.060.20 Pitna voda Drinking water
71.100.80 .HPLNDOLMH]DþLãþHQMHYRGH Chemicals for purification of
water
SIST EN 901:2007 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 901:2007
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SIST EN 901:2007
EUROPEAN STANDARD
EN 901
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2007
ICS 71.100.80 Supersedes EN 901:1999
English Version
Chemicals used for treatment of water intended for human
consumption - Sodium hypochlorite
Produits chimiques utilisés pour le traitement de l'eau Produkte zur Aufbereitung von Wasser für den
destinée à la consommation humaine - Hypochlorite de menschlichen Gebrauch - Natriumhypochlorit
sodium
This European Standard was approved by CEN on 10 February 2007.
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 CEN Management Centre 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 CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 901:2007: E
worldwide for CEN national Members.
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SIST EN 901:2007
EN 901:2007 (E)
Contents Page
Foreword.4
Introduction .5
1 Scope .6
2 Normative references .6
3 Description .6
3.1 Identification.6
3.1.1 Chemical name.6
3.1.2 Synonym or common names.6
3.1.3 Relative molecular mass.6
3.1.4 Empirical formula.6
3.1.5 Chemical formula.6
3.1.6 CAS Registry Number .7
3.1.7 EINECS reference .7
3.2 Commercial form .7
3.3 Physical properties.7
3.3.1 Appearance and odour.7
3.3.2 Density .7
3.3.3 Solubility in water .7
3.3.4 Vapour pressure .7
3.3.5 Boiling point at 100 kPa .7
3.3.6 Crystallization and freezing point .7
3.3.7 Specific heat.7
3.3.8 Viscosity (dynamic) .7
3.3.9 Critical temperature.8
3.3.10 Critical pressure.8
3.3.11 Physical hardness .8
3.4 Chemical properties .8
4 Purity criteria.8
4.1 General.8
4.2 Composition of commercial product.8
4.3 Impurities and main by-products.8
4.4 Chemical parameters .9
5 Test methods.9
5.1 Sampling.9
5.2 Analysis .9
5.2.1 Determination of available chlorine content (main product) .9
5.2.2 Impurities.12
5.2.3 Chemical parameters .18
2
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SIST EN 901:2007
EN 901:2007 (E)
6 Labelling - Transportation - Storage .20
6.1 Means of delivery .20
6.2 Risk and safety labelling according to the EU Directives .21
6.3 Transportation regulations and labelling.22
6.4 Marking.22
6.5 Storage .22
6.5.1 General .22
6.5.2 Long term stability .22
6.5.3 Storage incompatibilities.22
Annex A (informative) General information on sodium hypochlorite.23
A.1 Origin .23
A.2 Use .23
Annex B (normative) General rules relating to safety .25
B.1 Rules for safe handling and use .25
B.2 Emergency procedures.25
Annex C (normative) Determination of arsenic, antimony and selenium (atomic absorption
spectrometry hydride technique) .26
C.1 General principle .26
C.2 Interferences .26
C.3 Reagents.26
C.4 Apparatus.28
C.5 Procedure.30
C.6 Calculation .31
Annex D (normative) Determination of bromate ion content in sodium hypochlorite by liquid
chromatography of ions and UV detection.32
D.1 General .32
D.2 Interferences .32
D.3 Principle.32
D.4 Reagents.32
D.5 Apparatus.34
D.6 Procedure.34
Annex E (informative) Results of inter-laboratory tests on sodium bromate determination in
sodium hypochlorite commercial solutions.37
Annex F (informative) Environmental, health and safety precautions within chemical laboratories.38
Bibliography.39
3
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SIST EN 901:2007
EN 901:2007 (E)
Foreword
This document (EN 901:2007) has been prepared by Technical Committee CEN/TC 164 “Water supply”, 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 September 2007, and conflicting national standards shall be
withdrawn at the latest by September 2007.
This document supersedes EN 901:1999.
Significant technical differences between this edition and EN 901:1999 are as follows:
a) deletion of the reference to EU Directive 80/778/EEC of 15 July 1980 in order to take account of the latest
Directive in force (see [1]);
b) addition of the limit of the impurity sodium bromate as defined in the EU Directive 98/83/EC and the
method of determination.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and United Kingdom.
4
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SIST EN 901:2007
EN 901:2007 (E)
Introduction
In respect of potential adverse effects on the quality of water intended for human consumption caused by the
product covered by this European Standard:
a) this European Standard provides no information regarding whether the product may be used without
restriction in any of the Member States of the EU or EFTA;
b) it should be noted that, while awaiting the adoption of verifiable European criteria, existing national
regulations concerning the use and/or the characteristics of this product remain in force.
NOTE Conformity with this European standard does not confer or imply acceptance or approval of the product in any
of the Member States of the EU or EFTA. Use of the product covered by this European Standard is subject to regulation or
control by National Authorities.
5
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SIST EN 901:2007
EN 901:2007 (E)
1 Scope
This European Standard is applicable to sodium hypochlorite used for treatment of water intended for human
consumption. It describes the characteristics of sodium hypochlorite and specifies the requirements and the
corresponding test methods for sodium hypochlorite. It gives information on its use in water treatment. It also
determines the rules relating to safe handling and use of sodium hypochlorite (see Annex B).
NOTE While this standard is not applicable to sodium hypochlorite generated in-situ (see bibliographic reference [6])
the limits for impurities and chemical parameters apply.
2 Normative references
The following referenced documents are indispensable for the application 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 1233, Water quality - Determination of chromium - Atomic absorption spectrometric methods
EN 1483, Water quality - Determination of mercury
EN ISO 3696:1995, Water for analytical laboratory use - Specifications and test methods (ISO 3696:1987)
ISO 3165, Sampling of chemical products for industrial use - Safety in sampling
ISO 6206, Chemical products for industrial use - Sampling – Vocabulary
ISO 8288:1986, Water quality - Determination of cobalt, nickel, copper, zinc, cadmium and lead - Flame
atomic absorption spectrometric methods
3 Description
3.1 Identification
3.1.1 Chemical name
Sodium hypochlorite.
3.1.2 Synonym or common names
Liquid bleach, soda bleach, bleach lye.
3.1.3 Relative molecular mass
74,44.
3.1.4 Empirical formula
NaClO.
3.1.5 Chemical formula
NaClO.
6
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SIST EN 901:2007
EN 901:2007 (E)
1)
3.1.6 CAS Registry Number
7681-52-9.
2)
3.1.7 EINECS reference
231-668-3.
3.2 Commercial form
The product is supplied as an aqueous solution with an available (active) chlorine concentration up to a mass
fraction of 18 %.
3.3 Physical properties
3.3.1 Appearance and odour
The product is a clear yellowish-green solution with a faint chlorinous odour.
3.3.2 Density
The density of the product varies between 1,13 g/ml and 1,30 g/ml at 20 °C.
3.3.3 Solubility in water
The product is capable of being mixed with water in any proportion.
3.3.4 Vapour pressure
Approximately 2,5 kPa at 20 °C.
3)
3.3.5 Boiling point at 100 kPa
Not applicable.
3.3.6 Crystallization and freezing point
At about – 10 °C crystallization of NaOCl . 6 H O starts
2
Freezing of the concentrated product takes place between - 20 °C and - 30 °C.
3.3.7 Specific heat
The specific heat is 3,48 kJ/(kg.K) for a solution with an available active chlorine concentration of mass
fraction between 14 % and 15 % .
3.3.8 Viscosity (dynamic)
2,6 mPa.s at 20 °C.
1)
Chemical Abstracts Service Registry Number.
2)
European Inventory of Existing Commercial Chemical Substances.
3)
100 kPa = 1 bar.
7
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SIST EN 901:2007
EN 901:2007 (E)
3.3.9 Critical temperature
Not applicable.
3.3.10 Critical pressure
Not applicable.
3.3.11 Physical hardness
Not applicable.
3.4 Chemical properties
The product is an alkaline solution with a pH value greater than 11 at 20 °C.
It reacts with acids and acidic salts to form chlorine.
-
Vigorous reactions occur with reducing chemicals. It is a strong oxidant (E° for (ClO ) = 0,89 V).
Red
- + - -
ClO + 2H +2e → Cl + H O
2
4 Purity criteria
4.1 General
This European Standard specifies the minimum purity requirements for sodium hypochlorite used for treating
water intended for human consumption. Limits are given for impurities commonly present in the product.
Depending on the raw material and the manufacturing process other impurities may be present and, if so, the
user, and when necessary the relevant authorities, shall be notified.
NOTE Users of the product should check the national regulations to clarify whether it is of appropriate purity for
treating water intended for human consumption, taking into account raw water quality, required dosage, contents of other
impurities and additives used in the product that are not stated in this product standard
Limits have been given for impurities and chemical parameters where these are likely to be present in
significant quantities from the current production process and raw materials. If in the production process or
raw materials lead to the presence of significant amounts of impurities, by-products or additives, the user shall
be notified.
4.2 Composition of commercial product
Sodium hypochlorite is available only in solutions with concentrations up to 18 % active chlorine at the time of
delivery by the producer. Common concentrated products contain a minimum of 12 % active chlorine. Diluted
solutions are also available.
The concentration of sodium hypochlorite shall be equal to or greater than the value specified by the
manufacturer.
4.3 Impurities and main by-products
The product contains sodium chloride (NaCl) in equimolar amounts at minimum, and a small portion of sodium
hydroxide (NaOH) which keeps the product alkaline. Thus a little amount of sodium carbonate (Na CO ) can
2 3
be present, too.
8
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SIST EN 901:2007
EN 901:2007 (E)
The sodium chlorate (NaClO ) content shall not exceed a mass fraction of 5,4 % of available chlorine at the
3
time of delivery by the producer. The product shall be visibly free from deposits or suspended matter.
NOTE Sodium chlorate is a by-product of the manufacturing process and can be formed during storage (see 6.5.1).
4.4 Chemical parameters
The product shall conform to the requirements specified in Table 1.
Table 1 – Chemical parameters
Parameter Limit in mg/kg
of available chlorine
Type 1 Type 2
Arsenic (As) max. 1 5
Antimony (Sb) max. 20 25
Cadmium (Cd) max. 2,5 5
Chromium (Cr) max. 2,5 5
Lead (Pb) max. 15 15
Mercury (Hg) max. 3,5 5
Nickel (Ni) max. 2,5 10
Selenium (Se) max. 20 25
Limit in g/kg
of available chlorine
a
Sodium bromate max2,5 5,0
NOTE Cyanide, which does not exist in a strong oxidizing medium such as sodium
hypochlorite, is not a relevant chemical parameter. Pesticides and polycyclic aromatic
hydrocarbons are not by-products of the manufacturing process. For parametric values
of sodium hypochlorite on trace metal content in drinking water, see bibliographic
reference [1].
a
Sodium bromate is a by-product of the manufacturing process.
5 Test methods
5.1 Sampling
Observe the general recommendations of ISO 3165 and take account of ISO 6206.
5.2 Analysis
5.2.1 Determination of available chlorine content (main product)
5.2.1.1 General
This method applies to all commercial products with available chlorine contents within the range of 70 g/l to
170 g/l.
NOTE It detects all oxidizing agents being active in weak acidic solutions, i.e. hypochlorite/chlorine, iodate, and
partially chloramines, Fe(III), etc. Not covered under these conditions are bromate and chlorate.
9
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SIST EN 901:2007
EN 901:2007 (E)
5.2.1.2 Principle
Sodium hypochlorite reacts with potassium iodide to release iodine in the presence of acetic acid. The iodine
is titrated with sodium thiosulfate standard volumetric solution in the presence of starch indicator solution.
NOTE The titration can also be carried out potentiometrically by the aid of titration automates; when this occurs, the
addition of soluble starch is unnecessary.
5.2.1.3 Reagents
All reagents shall be of a recognized analytical grade and the water used shall conform to grade 3, as
specified in EN ISO 3696:1995 (de-ionized water for common laboratory purposes).
5.2.1.3.1 Potassium iodide solution, mass fraction 10 % .
Weigh, to the nearest 0,1 mg, 100 g of potassium iodide, iodate-free, and dissolve in water and dilute to 1 l.
5.2.1.3.2 Acetic acid concentrated, of purity at least of mass fraction 99 % .
5.2.1.3.3 Sodium thiosulfate standard volumetric solution, c(Na S O .5H O) = 0,1 mol/l.
2 2 3 2
Standard volumetric solutions are commercially available and eventually they have to be diluted.
Alternatively, a standard volumetric solution can be prepared by the following procedure:
Dissolve 24,8 g Na S O . 5 H O in a 1 000 ml one-mark volumetric flask in 0,75 l of water. After the
2 2 3 2
temperature has equalized, make up to the mark with water and mix thoroughly.
To standardize: Weigh, to the nearest 0,1 mg, 3,600 g (m) of dry potassium iodate. Dissolve in water in a
1 000 ml one-mark volumetric flask, make up to the mark with water and mix (standard reference solution
c(1/6 KIO ) = 0,1 mol/l ). Place 200 ml of water in a 500 ml stoppered conical flask, add (2 ± 0,5) g of
3
potassium iodide and stir to dissolve. Then introduce, by means of a pipette, 10,0 ml of sodium thiosulfate
solution for standardization, add (15 ± 1) ml of hydrochloric acid solution (diluted 1 + 1 by volume) and
(5 ± 1) ml of starch solution (5.2.1.3.4). Titrate immediately with the potassium iodate standard reference
solution until the appearance of a blue coloration that persists for 30 s. Record the volume (V ) of iodate used.
1
The actual concentration, c, of the sodium thiosulfate standard volumetric solution (Na S O .5H O), expressed
2 2 3 2
in moles/l is given by Equation (1):
V ×c
1 1
c = (1)
V
where
c is the concentration, expressed in moles/l, of the potassium iodate standard reference solution [c(1/6
1
KIO ) = 0,1 mol/l ];
3
V is the volume, in ml, of the sodium thiosulfate standard volumetric solution used for the
standardization (V= 10 ml);
V is the volume, in ml, of potassium iodate standard reference solution used in the titration.
1
10
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SIST EN 901:2007
EN 901:2007 (E)
5.2.1.3.4 Starch solution, mass fraction of 1 %:
Make a slurry with (1 ± 0,1) g of starch and (5 + 1) ml of water. Add (90 ± 5) ml of boiling water to the slurry.
Stir to dissolve it and cool the solution. This solution needs to be refrigerated to avoid the decomposition of the
starch which results in a vague end point. Keep the solution cool and use it within 1 week.
NOTE Commercial indicators for iodine titration exist and can be used in place of the described starch solution,
provided that their efficiency has been previously tested.
5.2.1.4 Apparatus
Ordinary laboratory apparatus and glassware.
5.2.1.5 Procedure
5.2.1.5.1 Test solution
Weigh to the nearest 0,1 mg 1 g of the laboratory sample (record mass m in grams) into a 250 ml conical
1
flask and dilute with water up to 100 ml.
5.2.1.5.2 Determination
Add 10 ml of the potassium iodide solution (5.2.1.3.1) and 5 ml of concentrated acetic acid (5.2.1.3.2).
Titrate at once with the sodium thiosulfate standard volumetric solution (5.2.1.3.3) until the iodine colour is
nearly gone. Add 3 ml of the starch indicator solution (5.2.1.3.4) and complete the titration until the
disappearance of the blue-black colour. Record the volume V , of the sodium thiosulfate standard volumetric
1
solution added.
5.2.1.6 Expression of results
The available chlorine (Cl ) content, C , expressed in mass fraction % (w/w), is given by Equation (2):
2 2
C = (V x c x 3,545) / (m ) (2)
1 1 1
where
V is the volume, in millilitres, of the sodium thiosulfate standard volumetric solution (5.2.1.3.3);
1
c is the concentration in moles per litre, of the sodium thiosulfate standard volumetric solution (see
5.2.1.3.3);
3,545 is the mass in milligrams of chlorine (Cl ) corresponding to 1 ml of sodium thiosulfate solution of
2
c(Na S O .5H O) = 0,100 mol/l;
2 2 3 2
m is the mass in g of the laboratory sample used to prepare the test solution (5.2.1.5.1).
1
11
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SIST EN 901:2007
EN 901:2007 (E)
5.2.2 Impurities
5.2.2.1 Determination of sodium chlorate content (NaClO )
3
5.2.2.1.1 General
This method is used to determine the chlorate content, in the range between 3,75 g/l and 15 g/l, in sodium
hypochlorite solutions for commercial use ; it is specific for these species.
5.2.2.1.2 Principle
Direct determination of chlorate ions in a diluted solution of sodium hypochlorite by ion chromatography with
suppressed conductimetric detection.
5.2.2.1.3 Reagents
All reagents shall be of a recognized analytical grade and the water used shall have a conductivity of
0,056 µS/cm (conform to grade 1, as specified in EN ISO 3696:1995).
5.2.2.1.3.1 Sodium carbonate and sodium hydrogen carbonate, eluant solution.
Mix one volume of sodium carbonate solution c(Na CO ) = 2 mmol/l with one volume of sodium hydrogen
2 3
carbonate solution c(NaHCO ) = 0,75 mmol/l.
3
5.2.2.1.3.2 Sulfuric acid solution c(H SO ) = 0,025 mol/l regenerant solution.
2 4
5.2.2.1.3.3 Helium gas, high purity, for degassing eluant and regenerant solutions.
5.2.2.1.3.4 Sodium chlorate stock solution at 1 g/l.
Weigh, to the nearest 0,000 1 g, 0,255 1 g of NaClO Dissolve in 200 ml of the water (grade 1, EN ISO
3
3696:1995).
5.2.2.1.4 Apparatus
Ordinary laboratory apparatus and glassware, together with the following.
5.2.2.1.4.1 Ion chromatograph.
5.2.2.1.4.2 Chemical suppressed conductivity detector.
5.2.2.1.4.3 Anionic column and pre-column:
Resin composed of 15 µm polystyrene/divinylbenzene substrate agglomerated with anion exchange latex that
has been aminated.
5.2.2.1.4.4 Data logger/plotter, able to record and d
...
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