Overview
EN ISO 20045:2024 - Measurement of the radioactivity in the environment - Air: tritium - Test method using bubbler sampling (ISO 20045:2023, corrected version 2023-09) is a CEN-endorsed standard that specifies a validated bubbler sampling technique to determine atmospheric tritium activity. The method traps tritium from air by bubbling sampled air through an aqueous trapping solution and provides formulae for calculating activity concentration for multi‑bubbler systems.
Key topics and technical requirements
- Scope and principle: Measurement of atmospheric tritium, primarily as tritiated water vapour (HTO), by trapping in water via bubbler sampling.
- Sampling systems: Formulae supplied for a four‑bubbler sampling train; applicable to a single trapping module of two bubblers when only HTO is present.
- Equipment and setup: Requirements for sampling head location, air flow rate, sampling duration and total sampled air volume.
- Trapping solution and preservation: Specifications and guidance for the aqueous trapping medium and conservation of samples.
- Analytical calculations: Procedures for calculating activity concentration, decision threshold, detection limit and coverage intervals; separate calculations for HTO and for tritiated gas compounds.
- Performance: Typical method detection limit range reported as 0.2–0.5 Bq·m−3 for a sampling duration of about one week.
- Annexes and supporting material: Informative annexes cover tritium technical data, trapping efficiency determination, preservation of solutions, example forms and calculation examples.
- Exclusions: The document does not cover laboratory test results reported in becquerel per litre of trapping solution as per ISO 9698 or ISO 13168.
Applications and practical use
- Environmental monitoring around nuclear power plants, research reactors and nuclear facilities.
- Routine atmospheric surveillance programs and long‑term trend monitoring of ambient tritium.
- Emergency response air monitoring where tritium release is suspected.
- Regulatory compliance, environmental impact assessments and radiological protection studies.
- Use by environmental laboratories, radiological protection services, national monitoring networks, consultants and research institutions engaged in air tritium measurement.
Who should use it
- Environmental monitoring labs and field sampling teams
- Nuclear facility operators and radiation protection officers
- National and regional environmental agencies and regulators
- Academic and research groups studying atmospheric radionuclides
Related standards
- ISO 9698, ISO 13168 - referenced for laboratory reporting conventions (excluded from this method)
- ISO/TC 85 and CEN/TC 430 - technical committees responsible for the standard’s development and CEN endorsement
EN ISO 20045:2024 provides a robust, reproducible bubbler sampling procedure for accurate measurement of atmospheric tritium, supporting reliable environmental surveillance and regulatory compliance.
