SIST EN 723:2009

SLOVENSKI STANDARD
SIST EN 723:2009
01-julij-2009
1DGRPHãþD
SIST EN 723:1998
%DNHULQEDNURYH]OLWLQH3RVWRSHN]DGRORþDQMHRJOMLNDQDQRWUDQMLSRYUãLQL
EDNUHQLKFHYLDOLILWLQJRYVVHåLJRP
Copper and copper alloys - Combustion method for determination of carbon on the inner
surface of copper tubes or fittings
Kupfer und Kupferlegierungen - Verfahren zur Bestimmung des Kohlenstoffs auf der
Innenoberfläche von Kupferrohren oder Fittings durch Verbrennen
Cuivre et alliages de cuivre - Méthode de détermination par combustion de la teneur en
carbone a la surface interne des tubes ou des raccords en cuivre
Ta slovenski standard je istoveten z: EN 723:2009
ICS:
77.150.30 Bakreni izdelki Copper products
SIST EN 723:2009 en,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST EN 723:2009

---------------------- Page: 2 ----------------------

SIST EN 723:2009
EUROPEAN STANDARD
EN 723
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2009
ICS 77.150.30 Supersedes EN 723:1996
English Version
Copper and copper alloys - Combustion method for
determination of the carbon content on the inner surface of
copper tubes or fittings
Cuivre et alliages de cuivre - Méthode de détermination par Kupfer und Kupferlegierungen - Verfahren zur Bestimmung
combustion de la teneur en carbone à la surface interne des Kohlenstoffs auf der Innenoberfläche von Kupferrohren
des tubes ou des raccords en cuivre oder Fittings durch Verbrennen
This European Standard was approved by CEN on 19 March 2009.
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: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 723:2009: E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------

SIST EN 723:2009
EN 723:2009 (E)
Contents Page
Foreword .3
1 Scope .4
2 Terms and definitions .4
3 Principle .4
4 Preparation of samples and test pieces .4
4.1 Preparatory procedures .4
4.1.1 General .4
4.1.2 Residual carbon content .5
4.1.3 Total carbon content .5
4.1.4 Potential carbon content .5
4.2 Preparation of samples .5
4.2.1 Tubes .5
4.2.2 Fittings .5
4.3 Cleaning of sample surfaces .5
4.3.1 Cleaning of inner surface of sample .5
4.3.2 Cleaning of outer surface of sample.6
4.4 Preparation of test pieces .7
4.4.1 Tubes .7
4.4.2 Fittings .8
5 Method for carbon content determination .9
5.1 General .9
5.2 Determination of the carbon content . 10
5.3 Determination of the blank value . 10
6 Expression of results . 10
7 Calibration . 11
8 Test report . 11
Bibliography . 12

2

---------------------- Page: 4 ----------------------

SIST EN 723:2009
EN 723:2009 (E)
Foreword
This document (EN 723:2009) has been prepared by Technical Committee CEN/TC 133 “Copper and copper
alloys”, the secretariat of which is held by DIN.
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 October 2009, and conflicting national standards shall be withdrawn at
the latest by October 2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 723:1996.
In comparison with the first edition of EN 723:1996, the following significant technical changes and one
significant editorial change were made:
 improvement of the accuracy of the method;
 extension of the scope of the standard to fittings of copper alloys;
 simplification by limitation to only one method for carbon content determination, namely that of infrared
absorption spectrometry:
[Method using tetrabutylammonium hydroxide (HTBA) and Method of determination by measurement of
differential electrical conductivity (coulometric) deleted];
 simplification by limitation to only one cutting method for tubes with diameters exceeding the furnace
diameter by deletion of the "longitudinal cutting method";
 change of Clause 2 "Normative References" into "Bibliography" with renumbering.
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 the United Kingdom.
3

---------------------- Page: 5 ----------------------

SIST EN 723:2009
EN 723:2009 (E)
1 Scope
This European Standard specifies a combustion method for determining the carbon content, if any, on the
inner surface of tubes of copper or fittings of copper or copper alloys.
This standard applies only to seamless, round copper tubes as specified for example in EN 1057 and
EN 13348 or fittings of copper or copper alloys as specified in EN 1254 (all parts).
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply:
2.1
residual carbon
C
R
carbon present in the chemical form of elemental carbon
2.2
potential carbon
C
P
carbon present in the chemical form of organic compounds
EXAMPLE Organic compounds: oils, greases, etc.
2.3
total carbon
C
T
sum of residual carbon and potential carbon
3 Principle
Combustion of the carbon present on the inner surface of a tube or fitting sample, carried out at a given
temperature in an oxygen flow.
Determination, by infrared absorption spectrometry, of the residual or total carbon content, or both, by
measurement of the carbon dioxide generated. Calculation of potential carbon content is by subtraction of the
residual carbon content from the total carbon content.
4 Preparation of samples and test pieces
4.1 Preparatory procedures
4.1.1 General
Carry out the procedures in 4.1.2, 4.1.3 or 4.1.4 depending on the carbon to be determined and taking
account of the following precautions:
a) metal cutting tool shall be free from protective paint;
b) clamps shall be flat and consist of copper, aluminium, steel or an alternative material. Alternative
materials shall not be detrimental to their cleanliness;
4

---------------------- Page: 6 ----------------------

SIST EN 723:2009
EN 723:2009 (E)
c) all tools and implements used for cutting or clamping samples shall be degreased before sample
preparation;
d) degreasing shall be done by wiping with a lint-free cloth containing absorbed tetrachloroethylene,
trichloroethylene or trichloroethane or, because of potential for environmental harm, other solvents of
equivalent performance, e.g. acetone. These solvents shall also be used for cleaning/immersion of
samples where appropriate;
e) suitable protective gloves should be used to ensure skin contact with the surface under test is avoided;
f) between the cleaning operation and the combustion operation, the test pieces shall be kept in a non-
contaminating environment, such as a clean laboratory or in a desiccator containing sodium hydroxide
pellets. The tests shall be completed within approximately 5 h of cleaning the sample, or if not, the
sample shall be re-cleaned.
4.1.2 Residual carbon content
a) prepare samples (see 4.2);
b) clean inner and outer surface of sample (see 4.3.1 and 4.3.2);
c) prepare test pieces (see 4.4).
4.1.3 Total carbon content
a) prepare samples (see 4.2);
b) clean outer surface of sample (see 4.3.2);
c) prepare test pieces (see 4.4).
4.1.4 Potential carbon content
Prepare separate samples and test pieces following the procedures in 4.1.2 and 4.1.3.
4.2 Preparation of samples
4.2.1 Tubes
Cut a sample approximately 30 cm long from a tube, using a metal-cutting saw or a pipe cutter. Deburr the
outer and inner edges of the sample ends, using a smooth file or a trimming blade, take care that any burrs
removed do not fall into the bore of the tube.
4.2.2 Fittings
Select sufficient fittings from the batch in order to be able to cut test pieces from them having a minimum total
2
internal surface area of 10 cm .
4.3 Cleaning of sample surfaces
4.3.1 Cleaning of inner surface of sample
The following steps shall be performed in a fume cupboard. Immerse the sample, for a minimum of 2 min in an
agitated bath of boiling chlorinated solvent, for example, analytical grade trichloroethylene or trichloroethane,
that shall be used as reference in case of dispute ensuring that the solvent baths are kept topped up, such
that the sample remains totally immersed in the solvent. Immerse the sample in a second, boiling solvent bath
for at least 30 s.
5

---------------------- Page: 7 ----------------------

SIST EN 723:2009
EN 723:2009 (E)
Remove the sample from the bath and place it vertically under a fume hood or on a grease-free plate in an
oven operating at a temperature of at least 80 °C for a minimum of 60 s, until the solvent has totally
evaporated.
Refresh both baths periodically, as appropriate, in accordance with written internal procedures.
4.3.2 Cleaning of outer surface of sample
4.3.2.1 General
Degrease the outside surface of the sample by wiping with a clean, lint-free, solvent-containing cotton cloth,
taking care to ensure that no fibres remain on the sample after wiping.
Clean the sample by chemical cleaning method, see 4.3.2.2, or for tubes in R250 and R290 material
1)
conditions only, the alternative mechanical cleaning method, see 4.3.2.3, except in cases of dispute or
preparation for blank value determination, may be used.
4.3.2.2 Chemical cleaning
4.3.2.2.1 Sealing
a) For annealed tubes only:
Squashing/flattening a 20 mm (approx.) portion of the tube extending from one end, betwe
...