EN ISO 21420: 2020
Protective gloves. General requirements and test methods
This standard is designed to ensure that the gloves themselves do not cause harm to the wearer and are comfortable to wear, without impeding the protective properties to the user.
Tests and requirements include the chemical innocuousness of glove materials (including, pH value, Chromium VI, Azo dyes, PAHs nickel release and DMFa – see below) as well as optional requirements for water vapour transmission and absorption of materials and new considerations for donning and doffing of gloves with a layered construction. Procedures to examine the sizing of the glove and the effect on finger dexterity are also covered.
General requirements for the information to be supplied with and marked on the glove are also outlined in this standard.
The length of the glove is measured by suspending it from the middle finger with a graduated rule having a rounded tip designed to fit the tip of the finger. The glove is manipulated to remove any wrinkles or folds and the minimum length is recorded. EN ISO 21420 does not include a list of minimum lengths for each glove size, however, gloves for special purpose may specify a minimum length but in such situations the manufacturer must demonstrate that they are fit for special purpose by a statement in the user instructions.
Sizing / Dexterity
Gloves are fitted on a hand of the size that they are intended to fit and comments are made regarding comfort and fit. The wearer will then try to pick up pins of varying size to provide an indication of dexterity. Five pins are defined of diameter from 5 mm to 11mm, clearly the smaller the diameter that can be picked up the greater the dexterity result.
The determination of pH value of both leathers and textiles on a glove is required. This pH value shall be greater than 3.5 and less than 9.5. The test samples are taken from the palm of the glove, if other part of the glove contains different material, these materials shall be tested separately. A prepared test sample is extracted in water by mechanical shaking; the aqueous extract is then decanted and the pH value determined by a pH meter. An excessive amount of acid or alkali in a material has been linked to skin dermatitis and may indicate poor process control.
Each leather shall be tested separately and comply with the requirement of less than 3mg/kg of chromium VI. The soluble chromium VI is leached from the leather in a phosphate buffer and the chromium VI content in the extract is quantified by High Performance Liquid Chromatography, or by a UV spectrophotometer. Chromium VI is a restricted substance under REACH annex XVII and a known allergen.
Azo colourants are dyes which have can produce a huge variety of colours with good colour fastness properties. There are no restrictions on the use of azo dyes, but restrictions do exist on 22 aromatic amines which can be derived from them. Applicable to all dyed leathers and textiles. Requirement: less than 30mg/kg for each of the carcinogenic aromatic amines.
Polycyclic aromatic hydrocarbons (PAHs) are large aromatic structures that consist of Carbon and Hydrogen only and are applicable to rubbers and plastics in direct contact with the skin. Requirement: less than 1mg/kg of each of the eight restricted PAHs.
Relevant for gloves that contain metallic components which come into prolonged contact with skin. If the metallic component is coated with a non-nickel coating, a corrosion step is carried out prior to testing to simulate wearing of the component in contact with the skin. Requirement: less than 0.5µg/cm2/week.
Dimethylformamide (DMFa) is used as a solvent in the polymerisation of polyurethane (PU). This can alter the viscosity of the reaction mixture and therefore the final product. Applicable to all materials containing polyurethane (PU). Requirement: less than 1,000mg/kg.