Overview
ISO 11665-1:2019 - Measurement of radioactivity in the environment - Air: radon-222 - Part 1 describes the origins of radon and its short-lived decay products and gives guidance on commonly used measurement methods. The standard focuses on measuring radon-222 activity concentration and the potential alpha energy concentration of its short-lived decay products in air, and on determining the inherent uncertainty associated with these methods.
Key points:
- Defines measurement categories: spot, continuous, and integrated methods
- Describes sampling, detection, calibration and quality-control considerations
- Includes informative annexes on radon origins, example measurement results and example test reports
Key technical topics and requirements
- Measurement categories: guidance on choosing between spot measurements (instantaneous), continuous monitoring (time-resolved) and integrated sampling (time-averaged).
- Sampling considerations: objectives, sampling duration, sampled air volume, installation and operational conditions affecting representativeness.
- Detection techniques: common detectors and methods referenced include ZnS(Ag) scintillation, gamma-ray spectrometry, liquid scintillation, air ionization, semiconductor alpha detectors, solid-state nuclear track detectors (SSNTD) and other ionization/discharge-based methods.
- Measurement process: treatment of influence quantities, calibration procedures, and quality control to ensure traceability (references ISO/IEC 17025 and IEC 61577 series).
- Results and reporting: expression of activity concentrations, potential alpha energy concentrations, uncertainty estimation, and contents of a compliant test report (examples in Annex C).
- Health context: emphasizes that radon decay products drive radiological risk and cites WHO guidance for indoor radon reference levels (recommended 100 Bq·m⁻³, not to exceed 300 Bq·m⁻³ where 100 is not practical).
Practical applications and users
ISO 11665-1:2019 is intended for:
- Environmental and radiological testing laboratories
- Public health authorities and regulators setting reference levels and inspection programs
- Building surveyors, architects and radon mitigation specialists performing indoor exposure assessments
- Environmental consultants and researchers conducting radon mapping, epidemiological studies, or soil/structure exhalation assessments
Typical uses:
- Designing radon measurement campaigns (indoor and ambient air)
- Selecting appropriate detectors and sampling strategies
- Ensuring calibration, quality assurance and uncertainty estimation for regulatory or research reporting
- Informing building codes and remediation strategies
Related standards and references
- ISO/IEC 17025 - laboratory competence
- IEC 61577-1/2/3 - radon and radon decay product instrumentation
- Other parts of ISO 11665 series (e.g., Parts 2–9, 11) cover specific methods, exhalation rates, soil measurements and building methodologies.
Open preview (PDF)Measurement of radioactivity in the environment — Air: radon-222 — Part 1: Origins of radon and its short-lived decay products and associated measurement methods