Nickel Release Testing
Nickel (Ni) is a kind of element that easily leads to allergy. Ni will be absorbed by skin in touch with the material containing Ni releasing. The most common allergy is that sweating makes Ni release in touchable parts. According to statistics, 20% of people have the Ni allergy. Clothing, jewelry and some commodity exporting to Europe are required to test Ni release commonly if the contents have metal accessories containing Ni.
EU the REACH Regulation No.1907/2006 XVII Safety Requirements
Nickel usually exists in plating, stainless steel and other alloys. Prolonged contact with excessive nickel may cause severe sensitization and lead to Dermatitis. In order to reduce these risks, the Nickel release was prescribed in Nickel Directive94/27/EC. Not until July 20 1999, EU published three standard—EN1810, EN1811 and EN12472 to state more accurate analysis method for nickel release , which shows precise quantitative analysis will be made to Nickel release. These procedures particular for specific group of metal products are list as below:
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Standard
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Scope
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Limit
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EN1810
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Body-piercing assemblies
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<0.05%Ni
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EN1811
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Body-piercing assemblies
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<0.2μg/cm2/Week
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Products directly prolonged contacting with skin
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<0.5μg/cm2/Week
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EN12472
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Coated items directly prolonged contacting with skin
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<0.5μg/cm2/Week
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Requirements of the Directive: For the following products, shall not be placed on the market unless they conform to the requirements.
(a.) in any post assemblies which are inserted into pierced ears and other pierced parts of the human body unless the rate of nickel release from such post assemblies is less than 0.2 μg/cm 2 /week (migration limit);
(b.) in articles intended to come into direct and prolonged contact with the skin such as:
—earrings
—necklaces, bracelets and chains, anklets, finger rings
—wrist-watch cases, watch straps and tighteners,
—rivet buttons, tighteners, rivets, zippers and metal marks
when these are used in garments, if the rate of nickel release from the parts of these articles coming into direct and prolonged contact with the skin is greater than 0.5 μg/cm2/week.
General methods for the Detection: according to the requirements of Directive 94/27/EC, items should be tested in accordance with the appropriate European harmonised standard(s), the references of which have been published by the European Commission in the Official Journal of the European Communities. , these are EN1811 and EN12472. The standards specify a quantitative method for the release of nickel from articles.
Procedure of the Detection: The item to be tested for nickel release is placed in an artificial sweat test solution for one week. The concentration of dissolved nickel in the solution is determined by atomic absorption spectrometry, inductively-coupled plasma spectrometry or other appropriate analytical method. The nickel release is expressed in micrograms per square centimetre per week (mg/cm2/week).
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