Metal Extraction
Standardized procedures for the textile industry provide a method for determining the concentration of extractable metals in various fabric types using synthetic perspiration solutions. This EN ISO 16711-1 protocol is used to assess the safety of garments that come into direct contact with the skin. The test mimics the way human sweat can leach heavy metals like lead, cadmium, or nickel out of the dyes and finishes on the cloth.
It is a critical check for infant clothing where the risk of exposure is higher due to the sensitivity of the skin. The standard applies to natural fibres, synthetic yarns, and any blends used in the production of soft goods.
Acid Treatment
Testing involves a controlled extraction process that uses a specific chemical buffer. A sample of the textile is weighed and placed in a container with a synthetic perspiration solution that has a pH of five point five. This acidity is designed to match the typical pH of human sweat.
The container is then agitated in a water bath at thirty-seven degrees Celsius for four hours. This temperature and duration simulate a long period of wear by a person. After the extraction, the liquid is filtered and analysed using high-precision equipment like an atomic absorption spectrometer.
This EN ISO 16711-1 method ensures that the results are reproducible across different laboratories. The concentration of each metal is calculated in milligrams per kilogram of fabric. If the levels exceed the limits set by brands or regional regulations, the fabric is deemed unsafe for use in apparel.
This process is particularly important for recycled materials where the history of the chemicals used in the original fibre is unknown. Recycled polyester or cotton can often contain traces of heavy metals from industrial dyes. By using this extraction method, brands can verify that the recycling process has removed these contaminants.
The accuracy of the test depends on the precise preparation of the synthetic sweat and the maintenance of the temperature during the extraction phase. Any variation in these factors can lead to inconsistent results and false passes in the quality control system.
Laboratory Scope
Capabilities of the testing facility must match the requirements of the international standard. A laboratory performing the EN ISO 16711-1 test must have the correct equipment to detect metals at very low concentrations. This often requires the use of inductively coupled plasma mass spectrometry for the most sensitive measurements.
The laboratory must also participate in proficiency testing to prove that its results are accurate compared to other facilities.
Safety Assessment
Evaluation of the final report is the responsibility of the quality manager at the garment factory or the brand. If the EN ISO 16711-1 results show a high level of extractable nickel, the brand may face legal action in markets like the European Union. Nickel is a common cause of contact dermatitis and is strictly regulated under the REACH framework.
This test provides the documentary evidence needed to prove that a product is safe for the consumer.
