Overview
ISO/TS 12828-3:2024 - Validation method for fire gas analysis, Part 3 provides guidance and techniques for conducting interlaboratory trials related to fire effluent (fire gas) analyses. The Technical Specification explains how to separate and evaluate the relative contributions of the physical fire model and the analytical techniques to laboratory results, and it clarifies challenges in interpreting interlaboratory data when assessing trueness and fidelity of measurements.
Key topics
- Scope and purpose: Techniques for designing and interpreting interlaboratory trials for fire effluent analyses; complements ISO 12828-1 (limits) and ISO 12828-2 (intralaboratory validation).
- Trueness and fidelity: Definitions and evaluation methods:
- Trueness (bias) vs. fidelity (precision), with guidance on z‑score (trueness indicator) and k‑score (fidelity indicator).
- z‑score interpretation: z ≤ 2 (satisfactory ≈95% range), 2 < z ≤ 3 (suspect), z > 3 (unsatisfactory).
- Sources of deviation:
- From the material/product tested.
- From the physical fire model (combustion, sampling and conditioning).
- From the analytical technique (sampling, conditioning, instrumental analysis).
- Types of interlaboratory trials:
- Trials that include the full fire model (combustion + analysis).
- Trials of analysis alone using standard gases or matrix spikes.
- Comparative trials between analytical techniques.
- Practical evaluation approaches:
- Mass-balance checks (e.g., halogen/chlorine → HCl, carbon → CO/CO2, sulfur → SO2) when theoretical yields are known.
- Use of standard gases or reference methods where the theoretical value is not directly available.
- Statistical concepts and symbols: repeatability (within-lab), reproducibility (between-lab), standard deviations, k‑score and z‑score formulas, and interpretation.
Applications
ISO/TS 12828-3:2024 is intended for practical use in:
- Fire testing laboratories performing effluent/toxicity measurements.
- Accreditation bodies and proficiency-testing scheme operators (consistent with ISO/IEC 17043).
- Analytical method developers and quality managers validating sampling and analysis chains.
- Fire safety engineers, toxicologists, regulators, and material manufacturers assessing human tenability, environmental impact and compliance of products in fire scenarios.
Related standards
This document is a practical toolbox for improving confidence in fire effluent measurements and interpreting interlaboratory trial results where the interplay of combustion dynamics and analytical performance matters.