Overview
ISO/TS 11665-12:2018 - Measurement of radioactivity in the environment - Air: radon-222 - Part 12 - defines the membrane one-side activity concentration measurement method to determine the radon diffusion coefficient of waterproofing materials. It applies to materials such as bitumen and polymeric membranes, coatings and paints, and sets out assumptions, boundary conditions, equipment, sample preparation, measurement and reporting requirements for laboratory testing.
Key facts:
- Scope: assessment of radon diffusion through waterproof materials (membranes, coatings, paints).
- Measurement range: D ≈ 10⁻⁵ m²/s to 10⁻¹² m²/s.
- Associated uncertainty: typically 10% to 40% depending on conditions and D value.
- Method: one-side activity concentration measurement (membrane sealed in a chamber on one side).
Key topics and technical requirements
- Principle and method: measures radon activity concentration on the downstream side of a sample to derive the radon diffusion coefficient under controlled boundary conditions.
- Equipment and setup: description of chambers, holders (caps), detectors and calibration needs.
- Sample preparation and mounting: requirements for fixing samples, sealing and ensuring reproducible decisive area/volume.
- Control measurements: radon-tightness verification, detector background, calibration and instrument statistical checks.
- Data processing: calculation of D, limits of detection, confidence intervals and uncertainty estimation following GUM principles.
- Test conditions and influencing factors: temperature, humidity, radon transfer coefficient in the boundary air layer (default range 0.001–0.1 m/s), and material thickness considerations.
- Quality management: calibration, traceability and reporting requirements; note that no certified reference materials are currently available for these materials, which affects direct fulfillment of some ISO 17025 metrological requirements.
- Reporting: standardized content for material-level reports, sample reports and archived data.
Applications and who should use it
This technical specification is practical for:
- Testing laboratories performing radon diffusion and barrier property tests on waterproofing membranes and coatings.
- Manufacturers of radon-proof insulation (bitumen, polymeric membranes, paints) validating product performance.
- Building designers and architects specifying radon-proofing systems in radon-prone areas.
- Regulatory bodies and building code authorities setting performance criteria for radon barrier materials.
- Radon mitigation consultants and construction quality assessors evaluating retrofit solutions.
Related standards
- ISO 11665 series (radon measurement in air), especially ISO 11665-1 (origins and measurement methods).
- ISO/TS 11665-13 (other test methods for radon diffusion).
- ISO 80000-10 (quantities and units - atomic and nuclear physics).
- ISO/IEC Guide 98-3 (GUM - uncertainty of measurement).
- ISO 17025 (laboratory competence - note: limited by lack of reference materials).
This specification supports consistent, comparable measurement of radon diffusion coefficients for waterproof materials, enabling product evaluation, regulatory compliance and safer building design in radon-affected regions.