Overview
ISO/TR 22305:2006 is a Technical Report from ISO/TC 126 that reviews international collaborative studies on cigarette smoke analysis to inform compliance tolerances for declared carbon monoxide (CO) yields (as referenced in ISO 8243). It compiles statistical estimates of measurement repeatability (r) and reproducibility (R) for the determination of nicotine‑free dry particulate matter (NFDPM), nicotine, water and carbon monoxide in cigarette smoke, and uses these data to propose practical tolerances for regulatory checks.
Key topics
- Statistical analysis of collaborative studies - aggregation and comparison of r and R values from multiple international studies (including the 2003 CORESTA study).
- Models for compliance tolerances - a statistical model combining within‑ and between‑laboratory variability, rounding effects and (where data allow) product variability to estimate tolerances for declared yields.
- Data sources and limitations - international collaborative studies and UK Department of Health survey data; product variability estimates are limited and treated cautiously.
- Recommendations - the report recommends setting CO compliance tolerances based on the combined evidence (see Applications below).
- Informative annexes - background on sampling, problems in CO determination, proposals from industry, analysis of bias, and the CORESTA study report.
Practical applications
- Regulators: use ISO/TR 22305 as the evidence base when defining or reviewing compliance tolerances for CO yields on cigarette packs and when designing verification programs.
- Manufacturers: benchmark laboratory performance, interpret measurement variability, and understand the statistical basis for tolerances in ISO 8243.
- Testing laboratories: assess their repeatability and reproducibility against international study results and apply confidence intervals in test reporting.
- Standards developers and policy makers: rely on the report’s synthesis of collaborative data when updating normative standards or guidance.
Practical takeaways:
- The report supports a recommended CO compliance tolerance of 20% (over a period of time) and 25% (at one point in time) with a minimum value recommended in the report (review advised as compliance data accumulate).
- r and R values reported reflect measurement variability on near‑identical test samples and must be combined with product and sampling variability for full compliance assessment.
Related standards
- ISO 8243 - Sampling cigarette populations and declared yield tolerances
- ISO 3308 - Routine analytical smoking machine requirements
- ISO 5725‑1 / ISO 5725‑2 - Methods for evaluating repeatability and reproducibility
- ISO 4387 - (related smoke constituent measurement methods)
ISO/TR 22305 is an informative companion to these standards, providing the statistical and collaborative‑study evidence needed to interpret and apply tolerances for cigarette smoke constituents.