EN 16523-1 chemical permeation testing of gloves
Considering the new EN 16523-1:2015 test method for gloves claimed to provide protection from permeation by chemicals.
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With increasing workplace health and safety requirements and customer awareness of ethical trading, it is important for businesses to protect employees from dangerous chemicals. To show that protective suits, gloves and footwear sold within the European Union have been type-approved against the PPE Directive 89/686/EEC, they must bear the CE certification symbol. Type-approval by a Notified Body is required for all 'complex' (category III) and 'intermediate' (category II) personal protective equipment (PPE) products. In order to display the CE logo for chemically protective gloves, the Notified Body assessing the gloves will require testing to have been carried out in accordance with testing standards specified in EN ISO 374-1:2016 – such as EN 16523-1:2015 to determine the resistance to permeation by chemicals. The results of this testing will determine the relevant pictogram symbols that can be used on the packaging and labelling.
Protective gloves and breakthrough times
Where hazardous chemicals cannot be substituted with non-hazardous alternatives or isolated from operatives, gloves and appropriate protective clothing should be worn. In order to demonstrate that the gloves offer the correct level of protection, testing to determine the chemical protection is required.
Permeation is the process by which a chemical moves through a material at the molecular level. Sometimes, permeation occurs without any physical changes to the material (such as swelling, cracking or a reduction in its elasticity), so the material can seem unaffected, even though it does not provide adequate protection.
With protective gloves, both the material the glove is made from and its thickness are important factors as to whether the glove will give sufficient protection against a particular chemical. A disposable natural latex glove will, for instance, often give barrier protection against only dilute aqueous chemicals. However, a thicker polychloroprene (Neoprene) or polyvinyl chloride (PVC) gauntlet would be expected to give acceptable resistance against organic solvents such as methanol and acetone.
To be certified as 'chemically protective' in accordance with EN ISO 374-1 and bear any of the conical flask pictograms illustrated in figure 1, the gloves must first satisfy the requirements for resistance to penetration in EN 374-2:2014 clauses 7.2 and 7.3 (figure 2). Penetration is the movement of a chemical through an imperfection, such as a pinhole or other defect, and is a physical phenomenon where the liquid passes through the material on a non-molecular level. Penetration is evaluated by filling the glove separately with air and water, followed by an assessment to determine if there is any leakage.
The resistance to permeation is assessed in accordance with EN 16523-1:2015. There are six different performance levels, (see table 1), depending on what is called the 'breakthrough time'. This is the time from the start of the test to the time the chemical is detected moving through the material at a defined rate of 1µg per cm2 per minute.
|Table 1: Classification of permeation performance levels|
|Measured breakthrough time (min)||Permeation performance level|
There is a list of 18 test chemicals in EN ISO 374-1 (see table 2), and a glove’s performance level against these chemicals defines the 'type' of chemical-resistant glove and, therefore, the pictogram used in glove marking. Gloves will be classified as ‘type C’ if at least performance 'level 1' is achieved against at least one of the 18 listed chemicals. ‘Type B’ classification is for gloves which meet a minimum of 'level 2' against at least three of the 18 chemicals, and 'type A' gloves are those which achieve a minimum performance level 2 against at least six of the 18 chemicals. The conical flask pictogram (figure 1) is displayed on the certified gloves, and the letters below the shield denote the relevant code letter of the chemicals that achieved at least the performance levels quoted when tested in accordance with EN 16523-1.
|Table 2: List of test chemicals specified in EN ISO 374-1:2016|
|Code letter||Chemical||CAS number||Class|
|E||Carbon disulphide||75-15-0||Organic compound containing sulphur|
|H||Tetrahydrofuran||109-99-9||Heterocyclic and ether compound|
|K||40 per cent Sodium hydroxide||1310-73-2||Inorganic base|
|L||96 per cent Sulphuric acid||7664-93-9||Inorganic mineral acid|
|M||65 per cent nitric acid||7697-37-2||Inorganic mineral acid|
|N||99 per cent acetic acid||64-19-7||Organic acid|
|O||25 per cent ammonia||1336-21-6||Organic base|
|P||30 per cent hydrogen peroxide||7722-84-1||Peroxide|
|S||40 per cent hydrofluoric acid||7664-39-3||Inorganic mineral acid|
|T||37 per cent formaldehyde||50-00-0||Aldehyde|
In addition to EN 374-2 and EN 16523-1 testing, the gloves also must meet with the requirements for general protective gloves in EN 420:2003 + A1:2009 clauses 4, 5 and 7. Clause 4 is concerned with the glove design and construction, resistance to water penetration (if applicable), innocuousness (confirming the materials used are not harmful to the wearer) and electrostatic properties (if required). Clause 5 details the comfort and efficiency of the glove and sets hand length and glove length requirements for different glove sizes. Clause 5 also specifies a method to determine the dexterity performance level and criteria for water vapour absorption and transmission, where these properties are required.
Testing at SATRA
SATRA has an extensive range of detection techniques for use with permeation testing. Many more challenge chemicals than the 18 listed in EN ISO 374-1 can be assessed against various types of materials and different constructions, and the chemistry laboratory is ISO 17025-accredited for testing to EN 16523-1. Submitted technical files for EC type-examinations must contain satisfactory test reports against EN 374-2, EN 16523-1 and EN 420, in order to be certified as being chemical-resistant. From the performance levels obtained in these reports, the product labelling and user instructions will inform the end user as to whether the gloves are suitable for use in their industry.
Notified Bodies such as SATRA are Europe-based organisations appointed by member state governments and notified to the European Commission on the basis of their ability to carry out examinations and tests required for CE marking of products for Europe.
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