CEN/TR 16364:2012
(Main)Influence of materials on water intended for human consumption - Influence due to migration - Prediction of migration from organic materials using mathematical modelling
Influence of materials on water intended for human consumption - Influence due to migration - Prediction of migration from organic materials using mathematical modelling
This Technical Report describes a procedure, based on a diffusion model, to be applied to the estimation of specific migration of substances into drinking water from organic materials intended to come into contact with drinking water.
The modelling approach is readily applicable to certain organic materials, as explained in this report. In principle, the diffusion modelling approach is applicable to other organic materials but practical difficulties, in relation to obtaining data to feed into the diffusion model, may restrict or prevent its application. Accordingly, in addition to the diffusion model, scientific estimation procedures for the required data inputs need to be considered.
The approach is normally applicable to organic substances that are soluble in the material matrix. Substances applied externally to a product made of an organic material, e.g. antistatic agents, lubricants, etc. are excluded from the diffusion modelling approach, as are electrolytes, salts, oxides and metals. Only organic substances with well-defined molecular weight or mixtures with well-defined ranges of molecular weights are amenable to the diffusion modelling approach.
The diffusion modelling approach is readily applicable to amenable organic materials in the form of a pipe or a sheet, where data such as material thickness is readily calculable. More complicated product shapes, such as fittings, require assumptions to be made.
It may not be possible to model the effects of test waters that are chemically active, for example test waters to which chlorine has been added to simulate chlorinated drinking water. This is because substances that migrate from a material into water containing chlorine can be converted by chemical reaction into substances with different properties.
Einfluss von Materialien auf Wasser für den menschlichen Gebrauch - Einfluss infolge der Migration - Abschätzung der Migration aus organischen Materialien mittels mathematischer Modellierung
Dieser Technische Bericht beschreibt ein Verfahren auf der Grundlage eines Diffusionsmodells, das für die Abschätzung der spezifischen Migration von Stoffen in Trinkwasser aus organischen Materialien für den Kontakt mit Trinkwasser verwendet wird.
Das Modellierungsverfahren ist einfach für bestimmte organische Materialien anwendbar, wie in diesem Bericht erläutert. Grundsätzlich ist die Verfahrensweise der Diffusionsmodellierung auf andere organische Materialien anwend¬bar, allerdings können praktische Probleme in Zusammenhang mit der Erhebung der Eingabedaten für das Diffusions¬modell ihre Anwendung einschränken oder verhindern. Dementsprechend müssen zusätz¬lich zum Diffusions¬modell wissenschaftliche Abschätzungsverfahren für die erforderlichen Eingabedaten erwogen werden.
Die Verfahrensweise ist gewöhnlich für organische Substanzen anwendbar, die in der Materialmatrix löslich sind. Stoffe, die von außen auf ein Produkt aus einem organischen Material aufgebracht werden, z. B. Antistatik¬mittel, Schmiermittel usw., sind von der Diffusionsmodellierung ebenso ausgeschlossen wie Elektrolyte, Salze, Oxide und Metalle. Ausschließlich organische Stoffe mit einer genau bestimmten Molekularmasse oder Gemische mit genau bestimmten Bereichen von Molekularmassen sind für die Diffusionsmodellierung geeignet.
Die Verfahrensweise der Diffusionsmodellierung ist einfach anzuwenden für geeignete organische Materialien in Rohr- oder Plattenform, für die Daten, wie z. B. Materialdicke, einfach zu berechnen sind. Bei komplizier-teren Produktformen, wie z. B. bei Formstücken, sind Annahmen erforderlich.
Die Modellierung der Einflüsse von chemisch aktivem Prüfwasser, z. B. Prüfwasser, dem Chlor zuge¬setzt wurde, um chloriertes Trinkwasser zu simulieren, ist möglicherweise nicht durchführbar. Dies ist darin begründet, dass Stoffe, die aus einem Material in chloriertes Wasser migrieren, durch chemische Reak¬tion in Stoffen mit veränderten Eigenschaften umgewandelt werden können.
Influence des matériaux sur l'eau destinée à la consommation humaine - Influence de la migration - Utilisation de modèles mathématiques pour prévoir la migration depuis des matériaux organiques
Le présent Rapport technique décrit un mode opératoire s’appuyant sur un modèle de diffusion, à appliquer afin d’estimer le niveau de migration spécifique de substances vers l’eau potable, depuis des matériaux organiques destinés à entrer en contact avec l’eau potable.
L’approche par modélisation est facilement applicable à certains matériaux organiques, comme expliqué dans le présent rapport. En principe, l’approche par modèles de diffusion peut être employée avec d’autres matériaux organiques, mais des difficultés d’ordre pratique, liées à l’obtention des données destinées à alimenter le modèle de diffusion, peuvent limiter ou empêcher son utilisation. En conséquence, outre le modèle de diffusion, des modes opératoires permettant une estimation scientifique des données de départ requises doivent être envisagés.
L’approche est normalement applicable aux substances organiques solubles dans la matrice du matériau. Les substances appliquées de manière externe à un produit composé d’un matériau organique, par exemple, agents antistatiques, lubrifiants, etc., sont exclus de l’approche par modèles de diffusion, tout comme les électrolytes, sels, oxydes et métaux. Seules des substances organiques de masse moléculaire bien définie ou des mélanges dont les plages de masses moléculaires sont bien définies sont compatibles avec l’approche par modèles de diffusion.
L’approche par modèles de diffusion est facilement applicable aux matériaux organiques compatibles se présentant sous la forme d’un tuyau ou d’une feuille, c’est-à-dire ceux pour lesquels on peut aisément calculer des données telles que l’épaisseur de matériau. Les formes de produits plus complexes, telles que les raccords, nécessitent de poser des hypothèses.
Il peut s’avérer impossible de modéliser les effets d’eaux d’essai chimiquement actives, par exemple des eaux d’essai auxquelles on a ajouté du chlore afin de simuler une eau potable chlorée. En effet, des substances migrant d’un matériau vers une eau contenant du chlore peuvent être transformées par réaction chimique en substances possédant des propriétés différentes.
Vpliv materiala na pitno vodo - Vpliv migracije - Ocenjevanje migracije iz organskih snovi z uporabo matematičnega modeliranja
To tehnično poročilo navaja postopek na osnovi difuzijskega modela, ki se uporablja za oceno posebne migracije materiala iz organskih snovi, namenjenih za stik s pitno vodo, v pitno vodo. Pristop z modeliranjem se uporablja za nekatere organske snovi, kot je pojasnjeno v tem poročilu. Pristop difuzijskega modeliranja se načeloma uporablja za druge organske snovi, vendar lahko težave v praksi, povezane s pridobivanjem podatkov za vnos v difuzijski model, omejijo ali preprečijo njegovo uporabo. Glede na to je treba poleg difuzijskega modela obravnavati postopke znanstvene ocene za zahtevani vnos podatkov. Pristop se običajno uporablja za organske snovi, ki so topne v matriki materiala. Snovi, kot so elektroliti, soli, oksidi in kovine, ki se na proizvod iz organske snovi, npr. antistatična sredstva, maziva itd., nanesejo od zunaj, so izključene iz pristopa z difuzijskim modeliranjem. Za pristop z difuzijskim modeliranjem so primerne le organske snovi z dobro opredeljeno molekulsko maso ali mešanice z dobro opredeljenimi območji molekulske mase. Pristop z difuzijskim modeliranjem se uporablja za primerne organske snovi v obliki cevi ali plošč, za katere je mogoče izračunati debelino materiala. Pri bolj zapletenih oblikah, kot so armature, so potrebne predpostavke. Morda ne bo možno modelirati učinkov preskusnih vod, ki so kemično aktivne, na primer preskusnih vod, ki jim je bil z namenom simuliranja klorirane pitne vode dodan klor. Razlog za to je dejstvo, da je mogoče snovi, ki migrirajo iz materiala v vodo, ki vsebuje klor, s kemijsko reakcijo pretvoriti v snovi z drugačnimi značilnostmi.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2012
9SOLYPDWHULDODQDSLWQRYRGR9SOLYPLJUDFLMH2FHQMHYDQMHPLJUDFLMHL]RUJDQVNLK
VQRYL]XSRUDERPDWHPDWLþQHJDPRGHOLUDQMD
Influence of materials on water intended for human consumption - Influence due to
migration - Prediction of migration from organic materials using mathematical modelling
Einfluss von Materialien auf Wasser für den menschlichen Gebrauch - Einfluss infolge
der Migration - Abschätzung der Migration aus organischen Materialien mittels
mathematischer Modellierung
Influence des matériaux sur l'eau destinée à la consommation humaine - Influence de la
migration - Utilisation de modèles mathématiques pour prévoir la migration depuis des
matériaux organiques
Ta slovenski standard je istoveten z: CEN/TR 16364:2012
ICS:
13.060.20 Pitna voda Drinking water
67.250 Materiali in predmeti v stiku z Materials and articles in
živili contact with foodstuffs
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL REPORT
CEN/TR 16364
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
June 2012
ICS 13.060.20
English Version
Influence of materials on water intended for human consumption
- Influence due to migration - Prediction of migration from
organic materials using mathematical modelling
Influence des matériaux sur l'eau destinée à la Einfluss von Materialien auf Wasser für den menschlichen
consommation humaine - Influence de la migration - Gebrauch - Einfluss infolge der Migration - Abschätzung
Utilisation de modèles mathématiques pour prévoir la der Migration aus organischen Materialien mittels
migration depuis des matériaux organiques mathematischer Modellierung
This Technical Report was approved by CEN on 9 April 2012. It has been drawn up by the Technical Committee CEN/TC 164.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, 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, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16364:2012: E
worldwide for CEN national Members.
Contents Page
Foreword .4
Introduction .5
1 Scope .7
2 Normative references .7
3 Terms and definitions .7
4 Principle .9
5 Apparatus .9
6 Assumptions that need to be valid .9
7 Required data inputs . 10
7.1 General . 10
7.2 Diffusion coefficient of the substance (D ) . 10
P
7.3 Partition coefficient of the substance (K ). . 10
P,W
7.4 Temperature of the system (T) . 11
7.5 Geometry of the material . 11
7.6 Material thickness, (d ). 11
P
7.7 Initial concentration of the substance in the material (c ) . 11
P,0
7.8 Chemical identity of the substance and its relative molecular weight . 11
7.9 Specific gravity of the material (ρρρρ ) . 11
P
7.10 Simulation of contact of organic material with test water . 11
8 Procedure . 11
9 Expression of results . 12
10 Report . 12
Annex A (informative) Principles of the modelling approach . 14
A.1 Migration modelling . 14
A.2 Initial and boundary conditions . 14
A.3 Solution of the diffusion equation . 15
A.4 Obtaining and using diffusion coefficients . 15
A.4.1 Diffusion coefficients from literature . 15
A.4.2 Diffusion coefficients from experiment . 16
A.4.3 Estimation of diffusion coefficients . 16
A.4.4 Upper-limit diffusion coefficient . 17
A.4.5 Validated AP', AP'* and ττττ values . 18
A.4.6 Diffusion coefficients for other materials . 18
A.4.7 Worst-case diffusion coefficients . 19
A.5 Obtaining and using partition coefficients . 19
A.5.1 General . 19
A.5.2 Partition coefficients from literature and from experiment . 19
A.5.3 Partition coefficients from experiment . 20
A.5.4 Estimation of partition coefficients. 20
A.5.5 Worst-case partition coefficients . 21
Annex B (informative) Examples of the application of modelling to migration of substances from
a material into drinking water . 22
B.1 Introduction . 22
B.2 Contact conditions . 22
B.3 Example calculations . 22
B.3.1 General . 22
B.3.2 Example 1, cold water test with the material constant in accordance to [7] . 23
B.3.3 Example 2 Cold water test with “realistic” material constants (experimentally measured) . 24
Annex C (informative) Validation of the numerical algorithm and software tools . 26
C.1 General . 26
C.2 Example A . 27
C.3 Example B . 28
Bibliography . 32
Foreword
This document (CEN/TR 16364:2012) has been prepared by Technical Committee CEN/TC 164 “Water
supply”, the secretariat of which is held by AFNOR.
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 has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
Introduction
During the last two decades, several scientific investigations have demonstrated that migration from organic
materials into liquid simulants is a physical process that can be modelled successfully. Mass transfer from an
organic material into a liquid simulant is predictable because in many cases it follows Fick´s law of diffusion,
i.e. the diffusion process is the rate determining step. To predict migration from organic materials into
contacting media a corresponding diffusion model was established.
This Technical Report describes the application of predictive diffusion modelling to the estimation of the
migration of a substance from a product intended for contact with water intended for human consumption – for
convenience, and where appropriate, referred to as drinking water in this report. The application applies to
organic materials, such as polymers, used to make such products.
The purpose of the report is to stimulate the use of such techniques in member states such that sufficient
experience is generated to enable the value of such modelling to be assessed in relation to complementing or
substituting the conventional approach.
Normally in member states the estimation of such migration is performed by standardised procedures based
on laboratory testing and analysis, i.e. an experimental approach. Migration modelling is an alternative to this
type of experimental testing. The experimental determination of the specific migration of substances into test
water (simulated drinking water) often requires a considerable amount of time and it can be costly. This
conventional approach has worked well and, of course, it generates data on the actual concentration of a
substance in test water. However, in some cases the analysis is difficult or even impossible due to problems
caused, for example, by chemical degradation, volatilisation of the substance. In addition, the substance may
not be amenable to, or the target concentration of interest may be too low for, available analytical techniques
Therefore, the application of a mathematical model could have considerable benefits for industry and
regulators, as experience has shown in the control of migration from plastic materials in contact with
foodstuffs.
Thus, the modelling approach is attractive because, in principle, it is quicker and more flexible than the
conventional testing approach, in that different exposure conditions can be readily investigated - and it should
be cheaper.
Modelling of migration has been used for several years in the United States as an additional tool in support of
regulatory decisions. Also, the European Union has introduced such diffusion modelling by means of
th
EU Directive 2001/62/EC (the 6 amendment of Directive 90/128/EEC), consolidated in Directive 2002/72/EC
as a compliance and quality assurance tool for plastic materials intended to come in contact with foodstuff [3].
The European project SMT-CT98-7513, Evaluation of Migration Models in Support of Directive 90/128/EEC,
successfully demonstrated the practical value of such diffusion models. The main objectives of this project
were to demonstrate:
the validity of migration models for compliance purposes;
that a relationship between the specific migration limit (SML) and the concentration of a substance in the
finished product can be established.
A report of this project has been finalised and the project results were published in a scientific journal [4]. As
indica
...
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