ISO/TC 45/WG 16 - Environmental aspects and sustainability

This document establishes a general framework and considerations for assessing the environmental fate of tyre tread chemical additives in cured polymer and tyre and road wear particles (TRWP) throughout a tyre lifecycle. This document is applicable to laboratory-generated TRWP from cured tread polymer of known composition. Testing strategies are described for assessing the environmental fate and transport of tyre chemicals in the following processes that can occur during the tyre lifecycle: a) transformation of chemical additives in tread during tyre curing; b) transformation of chemical additives during TRWP generation (tyre use); c) transformation of chemical additives during TRWP aging and weathering; d) leaching of chemical additives and transformation products from TRWP to water; e) availability of chemical additives and transformation products from TRWP in sediment ecosystems. Mass concentrations and fractions of chemicals released or available from TRWP for the five lifecycle steps are used to estimate a) cumulative fraction of tread chemical(s) and transformation product(s) released to water, and b) cumulative fraction tread chemical(s) and transformation products(s) environmentally available.

This document specifies a method for the generation of tyre and road wear particles (TRWP) in a road simulator laboratory that is representative of actual driving conditions. Guidance is provided for the road simulator system, test pavement and tyres, vacuum collection system, monitoring, and reporting. This method is applicable for the collection of TRWP from a known pavement and tyre type under realistic driving conditions without the inference of road surface contaminants (i.e. brake dust, exhaust, grease, etc.). There is a possibility that this method is not relevant for studded tyres.

ISO/TS 21396:2017 specifies a method for the determination of the soil or sediment mass concentration (μg/g) of tyre and road wear particles (TRWP) in environmental samples. ISO/TS 21396:2017 establishes principles for soil or sediment sample collection, the generation of pyrolysis fragments from the sample, and the quantification of the generated polymer fragments. The quantified polymer mass is used to calculate the concentration of TRWP in soil or sediment. These quantities are expressed on a TRWP basis, which includes the mass of tyre tread and mass of road wear encrustations, and can also be expressed on a tyre rubber polymer or tyre tread basis. NOTE Tyre and road wear particles are a discrete mass of elongated particles generated at the frictional interface between the tyre and roadway surface during the service life of a tyre. The particles consist of tyre tread enriched with mineral encrustations from the roadway surface.

ISO/TS 21522:2017 gives guidance on the quantitative test methods to measure chemical components in fumes emitted during the manufacturing process of rubbers (including storage) and considered hazardous. NOTE Quantification of the level of exposure allows selection of the correct type of protection for the operators and, after implementation of the protection, verification that the risk was eliminated by implementation of the selected protection.

ISO/TR 21275:2017, based on 95 publications, gives an overview of what is the composition of the fumes emitted during the rubber manufacturing processes. The results obtained confirm that rubber fumes are a complex and variable mix of chemicals which have a wide range of possible sources and origins, including chemicals generated from the chemical reactions occurring in the rubber compounds during processing and curing. Some of these chemical substances can be hazardous, others are not. This document demonstrates the need for International Standards to qualify and quantify the hazardous chemicals to which the operators in the factories producing rubber articles can be exposed to, allowing the identification and mitigation of potential health risks.

ISO/TR 24699:2009 provides guidelines for inclusion of environmental aspects in standards for rubber and rubber products. It proposes an approach which is directed at minimizing any adverse environmental impact of the products under consideration without detracting from the primary purpose of ensuring their adequate fitness for use. It closely follows the guidelines laid down in ISO 17422, with certain modifications to make it applicable to rubber and rubber products. The guidance provided by ISO/TR 24699 is intended primarily for use by standards writers. Over and above its primary purpose, however, ISO/TR 24699 provides guidance of value to those involved in design work and other activities where the environmental aspects of rubber and rubber products are being considered. It promotes the use of renewable, recycled and recyclable materials when environmentally beneficial and includes guidance on compliance with legislation concerning the end-of-life treatment of rubber products and the management of restricted and prohibited substances.

This document provides a framework for the characterization of physical and chemical properties of tyre and road wear particles (TRWP) using published analytical standards. It is applicable to laboratory-generated TRWP and TRWP collected in the environment. NOTE This framework focuses primarily on published ISO standards, but includes standards published by other entities such as ASTM and AFNOR. A brief summary and justification for each standard required to characterize the physical and chemical properties of interest are provided.