CEN/TS 16677:2014

SLOVENSKI STANDARD
01-julij-2014
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Ophthalmic optics - Reference method for the testing of spectacle frames and
sunglasses for nickel release
Augenoptik - Referenzprüfverfahren zur Bestimmung der Nickellässigkeit von
Brillenfassungen und Sonnenbrillen
Optique ophtalmique - Méthode d'essai de référence relative à la libération du nickel par
les montures de lunettes et les lunettes de soleil
Ta slovenski standard je istoveten z: CEN/TS 16677:2014
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CEN/TS 16677
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
May 2014
ICS 11.040.70
English Version
Ophthalmic optics - Reference method for the testing of
spectacle frames and sunglasses for nickel release
Optique ophtalmique - Méthode d'essai de référence Augenoptik - Referenzverfahren für die Bestimmung der
relative à la libération du nickel par les montures de lunettes Nickellässigkeit von Brillenfassungen und Sonnenbrillen
et les lunettes de soleil
This Technical Specification (CEN/TS) was approved by CEN on 15 March 2014 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, 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

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 16677:2014 E
worldwide for CEN national Members.

Contents Page
Foreword .4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .6
4 Principle .7
5 Sampling and preparation of test samples .8
5.1 Selection of test samples .8
5.2 Preparation and conditioning of test samples .8
6 Simulation of wear and corrosion .9
7 Coating test .9
7.1 General .9
7.2 Apparatus and consumables .9
7.3 Preparation of test samples for coating test . 10
7.3.1 Parts to be tested . 10
7.3.2 Dismantling and/or cutting and/or masking . 11
7.3.3 Determination of test area . 12
7.3.4 Preparation of electrical contact area . 12
7.4 Preparation of saline solution . 13
7.5 Procedure . 13
7.5.1 Preparation of the electro-chemical cell . 13
7.5.2 Insertion and connection of the test part in the electro-chemical cell. 13
7.5.3 Determination of open circuit potential and measurement of electrochemical impedance
of samples . 14
7.5.4 Calibration of the potentiostat . 14
7.6 Calculation of results . 14
7.7 Test report . 15
8 Release of nickel and its quantitative analytical detection (migration test) . 15
8.1 General . 15
8.2 Apparatus and consumables . 16
8.3 Preparation of test samples for migration test . 17
8.3.1 Parts to be tested . 17
8.3.2 Guidance on selection of test areas on the parts to be tested . 18
8.3.3 Dismantling and degreasing . 18
8.4 Procedure . 18
8.4.1 Preparation of test paper including determination of its area . 18
8.4.2 Preparation of artificial sweat solution. 19
8.4.3 Applying artificial sweat to the test paper and attaching it to the test sample . 21
8.4.4 Incubation of test sample with test paper attached (release of nickel into paper) . 21
8.4.5 Retrieval of the test paper from the test samples . 22
8.4.6 Analysis of the paper for nickel present . 22
8.5 Calculation of results . 24
8.6 Interpretation of results . 25
8.6.1 General . 25
8.6.2 Assessment of non-compliance . 25
8.7 Test report . 25
Annex A (informative) Cutting and masking of test samples (Coating test) . 27
A.1 Fronts . 27
A.2 Sides (temples) . 28
Annex B (normative) Selection of test areas and wrapping (Migration test) . 29
B.1 Rims . 29
B.2 Bridge and brace bar . 30
B.3 Sides (temples) . 31
B.4 Wrapping with sealing film . 32
Bibliography . 33

Foreword
This document (CEN/TS 16677:2014) has been prepared by Technical Committee CEN/TC 170 “Ophthalmic
optics”, the secretariat of which is held by DIN.
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.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus,
Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,
Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Introduction
This document has been prepared under Mandate M/448 issued by the European Commission in the
framework of Regulation (EC) No 1907/2006, REACH, in particular Commission Regulation (EC) No 552/2009
of 22 June 2009 amending regulation (EC) No 1907/2006 of the European Parliament and of the Council on
the Registration, Evaluation, Authorization and restriction of Chemicals (REACH) as regards Annex XVII
RESTRICTIONS ON THE MANUFACTURE, PLACING ON THE MARKET AND USE OF CERTAIN
DANGEROUS SUBSTANCES, PREPARATIONS AND ARTICLES.
The aim of the mandate is the revision of the method of analysis to detect the release of nickel from spectacle
frames and sunglasses.
The availability of the new reference method for the determination of the release of nickel from spectacle
frames and sunglasses will provide the reliable framework to enforce the limit value for nickel release of
0,5 µg/cm /week set forth by European Regulation. It will ensure a uniform application and control of the
European legislation in all member states.
Harmonising the test method for nickel release in all member states is vital with a view to protecting effectively
the health of the end consumer, that is, the spectacle wearer. Nickel allergy is still the most frequent contact
allergy in Europe and a significant health issue.
1 Scope
This document specifies the reference method for the testing of spectacle frames, ready-to-wear spectacles,
sunglasses and other items for eye and face protection for nickel release.
The reference method supports the demonstration of conformity with the limit value for nickel release of
0,5 µg/cm /week set forth by European Regulation.
The reference method involves the procedural steps shown in Figure 1 and described in Clause 4.
This document applies to those parts of metal spectacle frames and those metal parts of combination
spectacle frames that are intended to come into direct and prolonged contact with the skin of the wearer. This
document also applies to those relevant metal parts of ready-to-wear spectacles, sunglasses and other items
for eye and face protection.
NOTE The reference method for articles apart from spectacle frames, ready-to-wear spectacles, sunglasses and
other items for eye and face protection is specified in EN 1811.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 12472, Method for the simulation of wear and corrosion for the detection of nickel release from coated
items
EN ISO 3696:1995, Water for analytical laboratory use - Specification and test methods (ISO 3696:1987)
EN ISO 11380, Optics and optical instruments - Ophthalmic optics - Formers (ISO 11380)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
article
spectacle frame, ready-to-wear spectacles, sunglass or other item used for eye and face protection to which
the scope of this document applies
3.2
test sample
spectacle frame, ready-to-wear spectacle, sunglass or other item used for eye and face protection submitted
for testing
Note 1 to entry: Fronts or sides may be submitted separately for testing.
3.3
test part
that part of a test sample that is intended to come into direct and prolonged contact with the skin and shall be
tested
Note 1 to entry: These parts are defined in 7.3.1 (for the coating test) and in 8.3.1 (for the migration test).
3.4
test paper
piece of paper used for testing, at any stage of the procedure
3.5
extraction solution
solution obtained after extracting the test paper
3.6
appropriate tool
tool enabling the procedure to be performed without causing contamination by nickel or other metal ions,
either from the material of the tool or deposits on it
Note 1 to entry: Such tools could be made from plastics, titanium, or stainless steels.
3.7
appropriate equipment
equipment enabling the procedure to be performed without causing contamination by nickel or other metal
ions, either from the material of the equipment or deposits on it
4 Principle
Following the simulation of wear and corrosion for coated test parts, according to the method specified in
EN 12472, the reference method comprises the following procedural steps:
1) Coating test, applicable only to test parts with an organic coating, based on Electrochemical Impedance
Spectroscopy (EIS) and specified in Clause 7; the coating test aims at demonstrating that the coating of
the test sample is of sufficient quality to prevent the release of nickel, thereby ensuring that the test
sample's nickel release does not exceed the regulatory limit. The coating test is, however, sensitive to all
ions, so an article may pass the migration test even though it failed the coating test.
2) Migration test for nickel ion release, specified in Clause 8; the migration test makes provision for
quantitative testing for the amount of nickel released, to determine whether or not the article's nickel
release exceeds the regulatory limit. The migration test comprises two steps: Release of nickel by
artificial sweat into a test paper and the subsequent quantitative analytical detection of the nickel released
into the paper.
For an article that failed the coating test, either new test samples or, subject to the requirements of the person
ordering the test, the original test samples may be subjected to the migration test.
Figure 1 illustrates the procedure.
Requirements for sampling and guidance as to which parts of the articles shall be subject to testing (the test
parts) are given in 5.1, and in 7.3.1 (for the coating test) and 8.3.1 (for the migration test).
a
The coating test is sensitive to all ions, so an article may pass the migration test even though it failed the coating test.
Figure 1 — Flowchart
5 Sampling and preparation of test samples
5.1 Selection of test samples
Two specimens of each article to be tested shall be selected at random for either the coating or the migration
test.
The selected specimens shall be identified as test sample 1 and test sample 2.
Subject to the agreement by the person ordering the test, test samples used for the coating test can be tested
in a subsequent migration test, but not vice versa.
If a test sample is likely to be subjected to the migration test after the coating test, it shall be washed in
deionised water immediately after the coating test and allowed to dry to avoid corrosion from sodium chloride.
It is preferable that new test samples are used for the migration test.
Prior to performing the coating test (see Clause 7) and the migration test (see Clause 8), as applicable, all test
samples shall be prepared and conditioned as specified in 5.2, then be subjected to the simulation of wear
and corrosion as specified in EN 12472 (see Clause 6).
5.2 Preparation and conditioning of test samples
For spectacle frames, if not already fitted with dummy or demonstration lenses, the test samples shall be fitted
with a pair of suitable organic lenses within the range of -1,00 D to +1,00 D and with an edge thickness of
between 1,5 mm and 2,5 mm. These test lenses shall be edged either in accordance with the manufacturer's
electronic instructions or with a digitally controlled edging machine that uses the tracing made of the individual
test sample or, where appropriate, using a mechanical former in accordance with EN ISO 11380. The bevel
angle of the edged lens shall be 120° -2° +3° for spectacle frames featuring a rim with a groove.
Sides and fronts shall be separated from each other, and end covers (side tips) removed from sides where
appropriate. Unless they have a metal-bearing surface, remove nose pads before the wear phase.
Dismantling of sides from fronts may be done either by unscrewing the joint screw or by cutting the joint
across the charniers.
WARNING: Care shall be taken not to damage the coating on the frame on areas that are subsequently
tested, particularly the coating near the cut.
Ensure that all the separate test parts remain identified throughout all steps of the overall procedure.
6 Simulation of wear and corrosion
Prior to submission to the selected test, the test samples shall be subject to the method for simulation of wear
and corrosion according to EN 12472.
Fix fronts and sides separately onto the retaining system and slide into the rotating barrel.
When the accelerated wear and corrosion process is completed, remove the test samples. Gently swirl the
sample(s) for 2 min in degreasing solution at room temperature. Rinse thoroughly with de-ionised water.
Gently dry in a clean air stream or allow to dry on absorbent paper. After degreasing, handle the samples with
appropriate tools or clean laboratory gloves.
Remove lenses from fronts by unscrewing the closing block joint.
NOTE Pushing dummy lenses out is very likely to damage the coating, while the alternative test lenses specified in
EN ISO 12870 can be removed only by unscrewing.
Disassemble three-piece rimless fronts. Disassemble fronts of combination frames and remove any plastics
parts.
Then subject the test parts to the selected test: Coating test, see Clause 7, and/or migration test, see
Clause 8.
7 Coating test
7.1 General
The purpose of the coating test is to verify if the surface treatment of an article is able to limit the release of
metal ions (hence including nickel), in order to identify good quality coatings. Test samples that are not
identified as "pass" may be subjected to the migration test, see Clauses 4 and 5.
The parts of spectacle frames needing consideration are only those intended to come into direct and
prolonged contact with the skin of the wearer, see 7.3.1.
7.2 Apparatus and consumables
7.2.1 Masking agent, suitable for electroplating purposes and capable of electrically insulating the test part
from the saline solution. Application of more than one coat is acceptable, and may be preferable.
Test the masking agent to verify that it is suitable by using it to coat a metal rod without an organic coating
and show that the adhesion is good and impedance results are high (greater than 50 MΩ).
It is recommended that the masking agent be coloured or fluorescent, to make the masked areas more visible.
1)
NOTE Lacomit is the trade name of a suitable product.
7.2.2 Deionised water, according to EN ISO 3696:1995, grade 3 or to Ph.Eur., for rinsing and preparation
of the saline solution (7.4).
7.2.3 Sodium chloride of recognised pro analysis, p.a., grade or better, for preparation of the saline
solution (7.4);
7.2.4 Degreasing solution, Sodium Dodecyl Sulphate (SDS) at a concentration of 2 % in deionised water,
to clean the test samples after cutting, etc. and before testing. An appropriately diluted, neutral, commercially
available detergent may also be used.
7.2.5 Apparatus for preparation of 1 % saline solution in deionised water.
7.2.6 Electro-chemical cell, made of glass, suitable for mounting firstly a Standard Calomel (SCE) or
Ag/AgCl Reference Electrode, secondly a Graphite or Platinum Counter Electrode and thirdly, the test part.
NOTE The recommended counter electrode is a high density pure graphite rod, approximately 6 mm in diameter.
7.2.7 Laboratory clamps, suitable for holding the (cut) test sample, as required to immerse the selected
area in electrolyte in the electro-chemical cell, but keeping the electrical contact area dry.
7.2.8 Potentiostat, having the ability to perform A.C. Electrochemical Impedance Spectroscopy (EIS) at
1 Hz and having a current sensitivity of better than 1 pA.
2)
NOTE An example of suitable apparatus is Gamry apparatus series 600 with EIS 300 software package.
7.2.9 Electrical clamps, e.g. small crocodile clips, capable of providing secure electrical contact with the
test sample, reference and counter electrodes.
7.2.10 Calibration (dummy) cell, usually supplied by the potentiostat manufacturer together with the
instrument, appropriate to test the potentiostat in the impedance range expected.
7.2.11 Appropriate tools, needed to perform the procedure. See 3.6 for the definition of "appropriate" tools.
To prevent possible contamination by nickel or other metal ions, clean all tools well before use.
7.2.12 Laboratory gloves, e.g. latex or PVC, but not cotton.
7.2.13 Faraday cage; either an earthed Faraday cage, aluminium foil or conductive cloth to house the
electro-chemical cell during measurement.
7.3 Preparation of test samples for coating test
7.3.1 Parts to be tested
See subclause 5.1 for sampling requirements.
For testing of articles with the coating test, the parts to be tested are:

1)
Lacomit is an example of a suitable product available commercially. This information is given for the convenience of
users of this document and does not constitute an endorsement by CEN of this product. Equivalent products may be used
if they can be shown to lead to the same results.
2)
Gamry apparatus series 600 with EIS 300 software package is an example of a suitable product available
commercially. This information is given for the convenience of users of this document and does not constitute an
endorsement by CEN of this product.
a) the front, comprising the rims including the groove, the bridge and the brace bar (if applicable) but
excluding the pad arms and pad boxes, lugs and closing block joints;
b) sides (temples), including metal collets, but excluding the joints, a zone (ideally 10 mm) around the joints,
and areas intended to be protected by plastic end covers (tips).
For each of the two test samples, the front and the two sides shall be tested separately; all three parts shall
pass in order for the article to pass.
7.3.2 Dismantling and/or cutting and/or masking
7.3.2.1 General
Prior to submission to the coating test, the test sample shall have been subject to the method for simulation of
wear and corrosion according to EN 12472. See Clause 6.
Select and separate those parts (or areas) which are subject to testing from those that are not. This can be
achieved by one or more of the following:
a) dismantling (see 7.3.2.2);
b) cutting (see 5.2, 7.3.2.3 and Annex A);
c) masking (see 7.3.2.4 and Annex A).
Consider the need for preparing the electrical contact area (see 7.3.4) and for determination of surface area
(see 7.3.3) when deciding where to cut or which areas to mask. Masking any "complicated" details of the test
sample which would not come into direct and prolonged contact with the skin could simplify the determination
of surface area and/or enhance its precision.
Cutting of the test samples, to separate the parts (or areas) to be tested from those not to be tested, is
permissible, but should be avoided if at all possible.
NOTE Cutting can be avoided by masking all of the test sample except those parts (or areas) to be subjected to the
test.
CAUTION — If cutting is undertaken, great care shall be taken to avoid contamination of metal ions
e.g.
— from the base material;
— from metal particles getting underneath the masking;
— by damaging the organic coating that is near the cut and subsequently tested;
— metal on tools or fingers or workplace.
Ensure that all the separate parts of the test samples remain identified, e.g. test serial number, while not
physically touching or modifying them.
7.3.2.2 Dismantling
If not already removed for the simulation of wear and corrosion according to EN 12472, dismantle nose pads
from fronts.
7.3.2.3 Cutting
Cut the frame by hand-sawing or cutting pliers.
Cut edges and any other areas of the parts to be tested that are not covered by an organic coating, other
those intended for use as electrical contact areas (see 7.3.4), will require masking. See 7.3.2.4 for
requirements regarding masking.
Ensure that cut edges are rounded in order to help get a good even coating of masking agent.
7.3.2.4 Masking
Gently swirl the test sample(s) for 2 min in degreasing solution (7.2.4) at room temperature. Rinse thoroughly
and carefully with de-ionised water (7.2.2) and gently dry in a clean air stream or allow to dry on absorbent
paper.
NOTE This cleaning stage is intended to remove plasticisers from packaging, extraneous grease and skin secretions
due to handling, but not any protective coatings.
After degreasing, handle the test samples with appropriate tools or clean laboratory gloves.
Masking can be done by dipping or painting/brushing. Whichever method is used, ensure that the resulting
masking film is much thicker than the original coating of the test sample or the part thereof. Ensure that cut
edges are covered. Dip or paint/brush twice, allowing approximately 30 min between the applications. After
allowing the masking agent to dry for a minimum of 15 min inspect the quality of masking visually with a low-
powered (e.g. 2x to 5x) magnifier to ensure complete coverage of the appropriate areas. If required, apply an
additional layer(s) of masking agent. See Annex A for details.
Pad arms and pad boxes, and closing blocks including their screws shall be masked, if intended to be
immersed.
The grooves of rims do not need masking, but they may be masked during the dipping process in areas
adjacent to pad arms and lugs.
Other parts to be masked may depend upon the choice of electrical contact area and whether or not the test
sample is cut.
Allow the masking agent to cure completely. In the case of doubt, follow the masking agent manufacturer's
instructions. When allowing the masking agent to dry and cure, support the test sample so that the masked
areas are not in contact with a surface.
If the test parts will not be tested immediately after the masking agent has dried and cured, then protect them
from potential damage by wrapping with paper tissue or placing individually in a polythene bag.
7.3.3 Determination of test area
The measured value with the coating test method is always in impedance per area, expressed in units of
MΩ ⋅ cm . Therefore, the method involves a need for determination of the test area, which is the immersed but
unmasked surface area of the test sample.
Determine the test area to the nearest cm . Direct measurement of surface area may be used; CAD data from
the frame manufacturer and/or classical picture analyzer software may be helpful.
7.3.4 Preparation of electrical contact area
The following serve as the electrical contact areas:
— either the end of the side furthest from the joint, or the joint;
— joint end of the lug.
Abrade the electrical contact area e.g. with a hand-held rotary model-making tool, file, or emery or silicon
carbide paper, so that the organic coating is completely removed. Take care not to damage the rest of the
coating during this process.
NOTE Wear suitable protective equipment, if appropriate.
7.4 Preparation of saline solution
Prepare a solution of saline by dissolving 10 g ± 0,1 g of Sodium Chloride (7.2.3) in 1 l of deionised water
(7.2.2). Ensure that the test solution is at 25 °C ± 5 °C. Allow the saline solution to stabilize in an open
container for at least 24 h, but do not use beyond 7 days.
7.5 Procedure
7.5.1 Preparation of the electro-chemical cell
Wash the electro-chemical cell with deionised water (7.2.2) or with saline solution (7.4).
Fill the electro-chemical cell with saline solution (7.4). Change the solution at least once on each day of
testing.
Ensure that the reference and counter electrodes (e.g. calomel) have been immersed for a sufficient time
before use. If stored in a dry state they will need to be (if appropriate, filled with potassium chloride and)
immersed in deionised water or saline for a minimum of 8 h. The equipment therefore cannot be used
immediately after assembly.
7.5.2 Insertion and connection of the test part in the electro-chemical cell
IMPORTANT — The technique requires a very good electrical connection between the electrodes,
including the test part, and the potentiostat and a Faraday cage or other method to shield the electro-
chemical cell from stray electromagnetic radiation.
Immediately before the EIS measurement, verify that the electrical contact area on the test part is clean and
free from masking agent, and is not tarnished. If necessary, apply further abrasion to achieve this, while taking
care not to damage the coating in the test area.
Suspend the test part in the saline solution so that it is not resting on the bottom or touching the sides of the
cell, ensuring that the electrical contact area is above the level of the saline solution. Ensure that any area of
the test part that does not require testing is either masked or is above the level of the saline solution, while the
counter and reference electrodes are appropriately immersed according to the equipment manufacturer's
instructions. Because the distance between the test parts and the electrodes may affect the resistance in the
solution, the test part, counter and reference electrodes shall be arranged in a triangular arrangement with a
separation of approximately 50 mm between each.
NOTE 1 A convenient way to do this is for the counter and reference electrodes to be mounted at the 50 mm
separation on a piece of insulating material resting on the rim of the electro-chemical cell so that they remain permanently
in the saline while testing. A second piece of insulating material can then be used to mount the test part at the appropriate
distance.
Ensure that the electrical connections on the abraded contact area of the test part and the electrodes are tight.
NOTE 2 One method is to use a screwed terminal block to clamp firmly on the test part, with a braided copper flex in
the other end of the terminal block to make good contact with the crocodile clip on the potentiostat lead.
If a lid is used, bring the electrode leads through the lid to enable connection to the potentiostat (7.2.8).
Immerse the test part in the saline solution in the electrochemical cell for 3 min before measuring the EIS
response. Use either a Faraday cage or wrap the electrochemical cell in a conducting material, e.g. earthed
aluminium foil or conductive cloth.
7.5.3 Determination of open circuit potential and measurement of electrochemical impedance of
samples
After immersing the sample in the saline solution as specified in 7.5.2, set the instrument to measure the
impedance of the test sample at the fixed frequency of 1 Hz and with the amplitude of the applied signal at
10 mV rms. Most instruments will automatically set the DC potential at the Open Circuit Potential (OCP) found
at the beginning of the measurement. Take the first measurement of impedance as soon as possible after the
sample has been immersed in the saline for 3 min, and take the two subsequent measurements in as close a
succession as possible. Carry out the measurement at room temperature.
If the instrument does not automatically set the DC potential to the OCP of the sample, this will have to be
done manually.
Verify that the ratio {(highest impedance reading – lowest impedance reading)/lowest reading} is no greater
than 0,3 (30 %); if it is, check the connections and electro-magnetic shielding and re-measure the test part
after washing with deionized water, allowing to dry and waiting at least 24 h.
NOTE A different immersion time might change the test sample's electrical properties.
7.5.4 Calibration of the potentiostat
Verify the calibration of the potentiostat daily by running the test on the calibration dummy cell (7.2.10).
7.6 Calculation of results
Using the average of the three values obtained, report the impedance (|Z|) at 1 Hz in MΩ ⋅ cm to one decimal
place.
NOTE 1 Some models of potentiostat allow the operator to enter the surface area of the sample into the software
before starting the measurement. This type of equipment is likely to report the impedance in MΩ ⋅ cm . If the equipment
reports the impedance in MΩ, the value in MΩ ⋅ cm is obtained by multiplying the impedance in MΩ by the immersed
surface area in cm .
NOTE 2 In the latter case, multiplication is necessary because this is effectively a calculation for resistances in parallel,
not series.
Classify the test sample as pass or fail. A pass is considered to be an impedance greater or equal to the
threshold limit of 4,7 MΩ ⋅ cm , while a fail is considered to be an impedance lower than the threshold limit.
For each of the two test samples, each of the two sides and the front shall be tested separately, and each test
part shall pass in order for the article to pass.
NOTE 3 This threshold limit was established by a round robin test, in which the impedance in MΩ ⋅ cm was compared
with the nickel release. The threshold limit has been chosen both to allow a margin of safety and to include an allowance
for uncertainty of measurement.
NOTE 4 A pass result indicates that the article complies with the REACH regulation, while an article that fails releases
metal ions at a rate which may be a problem. As a coating test, Electrochemical Impedance Spectroscopy gives a result
that includes all metal ions, not just nickel ions. Therefore, the article could demonstrate compliance with the regulatory
limit by submission to the migration test.
7.7 Test report
The test report for each determination shall include at least the following information:
a) identification of the article or the test sample(s), respectively, including source, date of receipt,
description;
b) a reference to this document, i.e. CEN/TS 16677:2014;
c) documentation (verbal description and, optionally, photographs) of the parts of the test sample(s) and
their preparation, including whether or not the test samples were subjected to the simulation of wear and
corrosion according to EN 12472, and including the size of the test area, expressed in cm ;
d) test result and a statement on compliance or non-compliance of the article to the threshold value;
e) any unusual features observed during the determination;
f) starting and completion dates of test;
g) the date the instrument was last calibrated;
h) identification of laboratory carrying out the analysis;
i) signature of person responsible for the validation of the test report.
EXAMPLE The numerical values of the test result could be presented in the form of the table below:
Test Tested part Laboratory Test area Impedance per unit area a
Result
sample identification
[cm ] [Ω ⋅ cm ]
(pass or fail)
number number
1 right side
left side
front
2 right side
left side
front
b
Overall test result (pass or fail):
a
Defined by whether the impedance per unit area is greater than or equal to, or less than the threshold given in 7.6.
b
Defined by: Pass – all test parts pass, Fail – any (or all) test part(s) fails.
8 Release of nickel and its quantitative analytical detection (migration test)
8.1 General
The analysis for nickel released from the test sample into the test paper is based on extraction followed by
ICP-OES, or ICP-MS or GF-AAS.
The parts of articles needing consideration are only those intended to come into direct and prolonged contact
with the skin of the wearer, see 8.3.1.
Test papers impregnated with a known amount of nickel are used as control samples to monitor the
application and removal of the test strips and the analysis procedure.
8.2 Apparatus and consumables
8.2.1 Laboratory cellulose paper, of highly-absorbing type, with one side covered with polyethylene (PE),
capable of being cut into fine strips of width 1,5 mm without fraying, and for which the specific weight
(grammage) can be measured within an uncertainty of ± 0,5 %.
3)
NOTE A suitable product is LabSorb Ultra from Sartorius-Stedim Biotech.
8.2.2 Appropriate tools including
— craft knife (cutter), being very sharp in order to cut without tearing or fraying the laboratory cellulose
paper, e.g. a craft knife with replaceable blades or ones that can be snapped off to leave a new cutting
edge
— straight edge or ruler
— ruler or equivalent that allows estimation to 0,25 mm or better
— scissors, and
— tweezers.
See 3.6 for the definition of "appropriate" tools.
To prevent possible contamination by nickel, clean all tools well before use.
8.2.3 Laboratory balance, that is accurate to at least 0,1 mg.
8.2.4 Appropriate equipment, such as vessels and containers needed to perform the procedure.
See 3.7 for the definition of "appropriate" equipment.
The use of single-use equipment is recommended. If using reusable equipment, clean thoroughly before use
to prevent possible contamination by nickel.
8.2.5 Degreasing solution, to clean the test samples before testing. Dissolve 5 g of an anionic surface-
active agent such as sodium dodecylbenzene sulfate or sodium alkylaryl sulfate in 1 000 ml deionised water
(8.2.6). An appropriately diluted, neutral, commercially available detergent may be used.
8.2.6 Deionised water, of EN ISO 3696:1995, grade 2 for rinsing.
8.2.7 Reagents and apparatus for preparation of artificial sweat solution, as specified in 8.4.2.2 and
8.4.2.3.
8.2.8 Pasteur pipette or micropipette, for saturating the test paper with artificial sweat.
8.2.9 Absorbing paper, to put underneath the test paper when saturating with artificial sweat.
8.2.10 Stretchable sealing film, of laboratory quality, 5 cm wide and capable of being stretched easily in
one direction only.
3)
LabSorb Ultra from Sartorius-Stedim Biotech is an example of a suitable product available commercially. This
information is given for the convenience of users of this document and does not constitute an endorsement by CEN of this
product. Equivalent products may be used if they can be shown to lead to the same results.
4)
NOTE A suitable product is Stretchable Parafilm ® M Sealing Film.
8.2.11 Climate chamber for incubation of the test samples, capable of maintaining a temperature of
30 °C ± 2 °C and relative humidity of at least 95 % and equipped with racks or shelves to support the test
samples. The racks or shelves may be designed to hold several test samples stacked side by side,
horizontally and without contact with each other to avoid cross-contamination.
As an alternative to the climate chamber, an oven, capable of maintaining a temperature of 30 °C ± 2 °C,
together with transparent tight-closing container(s) and sample supports fitted in those container(s) to hold test
samples side-by-side above deionised water to maintain humidity. The test samples shall be placed
horizontally and without contact with each other to avoid cross-contamination.
8.2.12 Ultrasonic bath to perform the extraction, fitted with supports for the extraction flask(s).
8.2.13 Laboratory gloves, e.g. latex or PVC, but not cotton.
8.3 Preparation of test samples for migration test
8.3.1 Parts to be teste
...