ISO 11665-8:2019

Overview

ISO 11665-8:2019 - Measurement of radioactivity in the environment - Air: radon-222 - Part 8 - specifies methodologies for determining radon (radon-222) activity concentration in buildings. It defines the step‑by‑step approach for the initial investigation (to estimate the annual average indoor radon concentration) and for additional investigations (to identify radon sources, entry routes and transfer pathways). The standard also sets out requirements for immediate post‑mitigation testing, ongoing monitoring of mitigation effectiveness, and assessment of the sustainability of building behaviour with respect to radon. It does not prescribe building diagnostics or specific mitigation works.

Key topics and technical requirements

• Organization of measuring stages: a structured two‑stage process - initial investigation followed by additional investigations where needed.
• Selection and handling of measuring devices: guidance on choosing appropriate detectors and sampling methods, and on correct installation and removal.
• Location, number and installation of measuring points: requirements to define representative locations and homogeneous zones within buildings for reliable radon assessment.
• Building mapping: spatial presentation of measurement data to locate areas with elevated radon concentrations.
• Identification of sources and pathways: procedures for locating radon origin (soil, building materials, water) and entry/transfer routes (cracks, service ducts, buried levels).
• Data processing and analysis: requirements for processing sampling media, analysing results and estimating annual average activity concentration.
• Post‑mitigation testing and monitoring: immediate testing after remediation, ongoing effectiveness control and tests for long‑term sustainability of mitigation measures.
• Reporting requirements: recommended content for initial and additional investigation reports to support decision‑making and regulatory compliance.

Practical applications

• Conducting compliant indoor radon surveys in single‑family homes, public or industrial buildings, and underground structures.
• Producing building radon maps to direct targeted diagnostics or mitigation.
• Verifying the effectiveness of radon mitigation systems and monitoring long‑term performance.
• Supporting regulatory compliance, public health risk assessments and building safety audits.
• Informing building owners, facility managers and remediation contractors about where to focus interventions.

Who should use this standard

• Radon measurement professionals and accredited testing laboratories
• Environmental health and safety officers, public health authorities and regulators
• Building surveyors, facility managers and construction professionals involved in radon prevention and control
• Consultants and contractors performing post‑mitigation verification and monitoring

Related standards

• ISO 11665 series (General guidance and measurement methods) - see particularly:
  • ISO 11665-1 (origins and measurement methods)
  • ISO 11665-4 (integrated passive sampling and delayed analysis)
  • ISO 11665-7 (surface exhalation rate accumulation method)
• ISO 6707-1 (building vocabulary)

Keywords: ISO 11665-8, radon measurement, radon in buildings, indoor radon, initial investigation, additional investigations, post-mitigation testing, radon mitigation, radon activity concentration, building mapping.