ISO 21438-3:2026

Overview

ISO 21438-3:2026 outlines a standardized method for determining the time-weighted average mass concentrations of soluble particulate fluorides and hydrofluoric acid (HF) in workplace air. Using ion chromatography, the method collects particulates on a pre-filter and HF on an alkali-impregnated filter. This procedure enables accurate occupational exposure assessment and compliance with workplace health and safety requirements. The standard applies to both personal and static (area) sampling, supporting effective industrial hygiene and risk management for environments where exposure to HF and particulate fluorides is of concern.

Key Topics

• Sampling and Collection: The standard specifies the sequential use of a pre-filter (for soluble particulate fluorides) and an alkali-impregnated filter (for HF) inside suitable samplers. This setup aligns with ISO 7708 for inhalable fractions, ensuring relevance to airborne hazard monitoring.

• Ion Chromatography Analysis: After sample collection, both filters are extracted, and their analytes are quantified via ion chromatography with conductivity detection. This analytical approach facilitates separation and specific detection of fluoride ions in complex matrices.

• Applicable Range: The method is validated for the measurement of particulate fluoride masses ranging from 0.005 mg to ≥1.25 mg per sample, and HF masses from 0.015 mg to ≥1.2 mg per sample, covering typical workplace exposure levels.

• Performance and Compliance: The procedure is designed to meet ISO 20581 requirements for workplace chemical agent measurement and emphasizes accuracy, precision, and use of validated calibration standards.

• Sample Handling and Quality Control: Detailed guidance is provided on cleaning, loading, transporting, and analyzing samples. Quality assurance measures include the use of blanks, certified reference materials, and regular calibration checks.

Applications

ISO 21438-3:2026 is widely applicable in various industrial and research settings:

• Occupational Exposure Assessment: Enables employers, industrial hygienists, and regulatory agencies to monitor exposure to hydrofluoric acid and particulate fluorides, essential for maintaining workplace safety and compliance.

• Industrial Hygiene: Vital for industries where HF or soluble fluorides are present-such as chemical manufacturing, metal treatment, glass etching, and electronics-by providing validated methods for routine air monitoring.

• Risk Management and Regulatory Compliance: Supports establishment and verification of compliance with occupational exposure limits, contributing to a proactive health and safety management system.

• Analytical Laboratories: Gives laboratories the protocols needed for consistent sample handling, analysis, and reporting, ensuring results are comparable and defensible.

• Workplace Environment Research: Facilitates epidemiological studies and research on worker health by providing standardized data collection on airborne inorganic acid hazards.

Related Standards

Standards referenced and often used in conjunction with ISO 21438-3:2026 include:

• ISO 7708 – Defines health-related fractions for airborne particles, ensuring proper sampler selection.
• ISO 3696 – Specifies laboratory water quality for reliable sample preparation and analysis.
• ISO 20581 – Sets out general requirements for chemical agent measurement procedures in workplace air.
• ISO 8655 (Parts 1, 2, and 6) – Details specifications and validation procedures for volumetric laboratory equipment such as pipettes.
• EN 13205 – Covers performance assessment of workplace airborne particle instruments.
• ISO 18158 – Provides workplace air terminology for consistency across documentation and reporting.

By implementing ISO 21438-3:2026, organizations reinforce their commitment to occupational health, environmental safety, and regulatory compliance when monitoring hydrofluoric acid and particulate fluorides in workplace atmospheres.