ISO/TR 27245:2020 — Nanotechnologies — Framework for Risk Management of Manufactured Nanomaterials

The rapid commercialisation of manufactured nanomaterials has created an urgent need for systematic risk management frameworks that address the unique challenges posed by the nanoscale. ISO/TR 27245:2020 provides a structured and comprehensive framework for the risk management of manufactured nanomaterials, integrating hazard identification, exposure assessment, risk characterisation, and risk control into a coherent methodology applicable across the entire product lifecycle. This article provides a detailed technical examination of the standard, its underlying principles, and practical strategies for effective implementation in industrial and research settings.

The Risk Management Framework Architecture

ISO/TR 27245 is built on a four-stage iterative framework that aligns with the ISO 31000 risk management principles while incorporating nanomaterial-specific adaptations. The first stage, Context Establishment, requires organisations to define the scope of risk management activities, identify relevant stakeholders, and establish the criteria for risk evaluation. This includes documenting the nanomaterial identity (chemical composition, crystal structure, particle size distribution, surface area, surface chemistry, and shape), the intended application, and the potential exposure scenarios across the lifecycle — from raw material handling through manufacturing, use, and end-of-life disposal or recycling.

The second stage, Risk Assessment, comprises three sub-stages: hazard identification, hazard characterisation (dose-response assessment), and exposure assessment. The standard emphasises that nanomaterial hazard assessment cannot rely solely on bulk material toxicity data, as nanoscale properties — particularly high surface-to-volume ratio, surface reactivity, and ability to cross biological barriers — can lead to toxicological profiles fundamentally different from the bulk counterpart. A tiered testing approach is recommended, starting with in vitro screening assays (e.g., oxidative stress, inflammation markers, cell viability) and progressing to in vivo studies only when justified by screening results and expected exposure levels.

Exposure Assessment and Control Strategies

A significant portion of ISO/TR 27245 is devoted to exposure assessment, recognising that occupational and environmental exposures to manufactured nanomaterials represent the primary pathways for potential adverse effects. The standard describes measurement strategies for workplace aerosol monitoring, including personal sampling (respirable and inhalable fractions) and real-time monitoring using condensation particle counters (CPCs), optical particle counters (OPCs), and scanning mobility particle sizers (SMPS). For each technique, the standard provides guidance on detection limits, selectivity for nanoparticles versus background aerosols, and data interpretation. A key recommendation is the use of multiple metrics: number concentration (particles/cm³), surface area concentration (μm²/cm³), and mass concentration (μg/m³), as no single metric adequately captures all aspects of nanomaterial exposure.

The risk control framework follows the established hierarchy of controls: elimination, substitution, engineering controls, administrative controls, and personal protective equipment (PPE). For nanomaterials, engineering controls — particularly local exhaust ventilation (LEV) with HEPA filtration, enclosed process equipment, and glove boxes — are emphasised as the most effective approach. The standard notes that conventional PPE, including filter respirators (FFP3/N100) and protective gloves, must be validated for nanoparticle penetration, as nanomaterials can penetrate through defects and filter media that are effective against larger particles. The effectiveness of control measures should be verified through regular monitoring programs, including both continuous real-time measurements and periodic comprehensive sampling campaigns.

Engineering Design Insights

From an engineering perspective, integrating risk management into the design phase — often referred to as “safe-by-design” — is the most efficient strategy for managing nanomaterial risks. ISO/TR 27245 supports this approach by providing a framework for identifying risk issues early in product development when design changes are least costly. Key safe-by-design strategies include: (1) selecting less hazardous nanomaterial morphologies (e.g., spherical rather than fibrous), (2) surface functionalisation to reduce reactivity, (3) encapsulation or immobilisation of nanoparticles in a matrix, and (4) designing products and processes to minimise nanoparticle release during use and end-of-life.

The standard also addresses the challenge of risk communication along the value chain, recognising that downstream users and consumers need adequate information to manage risks associated with nanomaterials in products. Safety data sheets (SDSs) for nanomaterials should include nano-specific information such as particle size distribution, surface area, surface chemistry, and agglomeration state, in addition to conventional hazard information. The framework recommends establishing clear communication channels between suppliers, manufacturers, users, and waste managers to ensure that risk management information flows effectively throughout the product lifecycle.

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