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ISO 26367-2:2017 — Guidelines for Assessing the Adverse Environmental Impact of Fire Effluents — Part 2: Methodology for Compiling Data
A systematic methodology for compiling environmentally significant emission data from fires
1. Data Quality Objectives and Sampling Programme Design
ISO 26367-2:2017 provides a rigorous methodology for compiling data on environmentally significant emissions from fires. The standard establishes a systematic framework beginning with clearly defined data quality objectives (DQOs) that drive every subsequent decision in the assessment process.
DQOs must include a problem statement, identification of affected area status, prioritization of decisions, data requirements, boundary definitions (spatial, temporal, demographic, regulatory), logical comparison basis, and acceptable uncertainty specifications.
The sampling programme design follows a decision flow chart that evaluates potential emissions across all environmental phases—air, water, and soil. The standard references critical International Standards for each medium: ISO 5667-1 for water sampling, ISO 11771 for air and fire plume sampling, and ISO 10381-1 for soil sampling. Natural background levels must be measured upwind of the fire plume zone and upstream of the deposition zone to establish baselines.
| Environmental Phase | Reference Standard | Key Measurements |
|---|---|---|
| Air / Fire plume | ISO 11771 | Time-averaged mass emissions, emission factors |
| Surface water / Groundwater | ISO 5667-1, ISO 5667-20 | Flow rate, pollutant concentrations, timing |
| Soil / Sediment | ISO 10381-1 | Sampling programme design, depth profiling |
2. Pollutant Selection and Characterisation
The standard mandates the inclusion of specific indicators and pollutants in any environmental compilation, with justification required for any exclusions. Indicators of environmental pollution include alkalinity, BOD, COD, electrical conductivity, hydrocarbon screening, pH, turbidity, and water quality (luminescent bacteria).
Short-term effect pollutants: Halogenated acids (HX), metals, NOx, particulates, SOx, and VOCs — primarily affecting air quality and causing immediate ecological stress in the fire plume zone.
Long-term effect pollutants: Metals, particulates, perfluorinated compounds (PFC), PCBs, PCDD/PCDF, PAHs, and VOCs — persisting in sediments, soils, and groundwater for years after the fire event.
Perfluorinated compounds (PFC), particularly PFOS and PFOA found in aqueous film-forming foams (AFFF), are extremely persistent in the environment and have been detected in human blood worldwide. PFOS was listed by the Stockholm Convention in 2009. When AFFF is used, run-off water must be analysed for PFC contamination.
The standard introduces toxicity equivalence (TEQ) methodologies for comparing complex mixtures. For PAHs, the benzo(a)pyrene (BaP) toxicity model assigns TEF values to 16 common PAH compounds, with BaP set at 1.0 and naphthalene at 0.001. Similarly, the WHO-TEF system for dioxins assigns 2,3,7,8-TCDD a factor of 1.0, enabling weighted summation of total dioxin toxicity.
3. Engineering Design Insights: Reporting Framework and Practical Application
The standard provides a comprehensive reporting template (Annex D) that serves as a practical tool for environmental professionals. The report structure includes: intent and scope of the report, incident description, characterization of contamination levels, evaluation of methodology, and findings.
Key engineering insights for practitioners:
- Baseline data is essential: Pre-fire reference concentrations make post-fire assessments meaningful. The standard requires measurement of natural levels upwind and upstream of the affected area.
- Modelling is an accepted alternative: When physical measurements are not feasible, predictive models (e.g., dispersion models, toxicity comparison models) can be used, but must be clearly identified with version and source references.
- Uncertainty must be quantified: Every measurement and prediction must include uncertainty estimates, enabling defensible decision-making in regulatory and legal contexts.
- Professional judgement is recognised: The standard explicitly acknowledges that environmental professionals must exercise judgement in evaluating fires, establishing DQOs, and interpreting results when validated information is unavailable.
The standardized reporting format in Annex D is designed for multiple use cases: risk assessment, environmental impact reports (EIR/EIS), damage assessment, forensic investigation, and life cycle assessment inventory. This flexibility makes it suitable for a wide range of stakeholders including environmental regulators, firefighters, insurers, and industrial facility operators.
FAQ 1: What are data quality objectives and why are they important?
DQOs are performance criteria that define the quality of data needed to support specific decisions. They ensure that sampling, analysis, and reporting efforts are proportionate to the intended use of the data and provide a clear framework for evaluating uncertainty.
DQOs are performance criteria that define the quality of data needed to support specific decisions. They ensure that sampling, analysis, and reporting efforts are proportionate to the intended use of the data and provide a clear framework for evaluating uncertainty.
FAQ 2: How do I select which pollutants to analyse after a fire?
The standard provides mandatory pollutant lists for short-term and long-term effects. Additional pollutants should be included based on the fuel composition (e.g., brominated dioxins if brominated flame retardants are present). Exclusion justification is required for any listed pollutant.
The standard provides mandatory pollutant lists for short-term and long-term effects. Additional pollutants should be included based on the fuel composition (e.g., brominated dioxins if brominated flame retardants are present). Exclusion justification is required for any listed pollutant.
FAQ 3: What is the role of toxicity equivalence (TEQ) in fire effluent assessment?
TEQ allows complex mixtures of related compounds (e.g., 16 PAH congeners or 17 dioxin/furan congeners) to be expressed as a single weighted value relative to the most toxic reference compound, simplifying comparison across different fire scenarios.
TEQ allows complex mixtures of related compounds (e.g., 16 PAH congeners or 17 dioxin/furan congeners) to be expressed as a single weighted value relative to the most toxic reference compound, simplifying comparison across different fire scenarios.
FAQ 4: Can modelling replace physical sampling for fire effluent assessment?
Modelling can supplement physical sampling when direct measurement is not feasible. However, the model must be clearly identified with source, version, and uncertainty estimates. Physical measurement remains the preferred approach when practical.
Modelling can supplement physical sampling when direct measurement is not feasible. However, the model must be clearly identified with source, version, and uncertainty estimates. Physical measurement remains the preferred approach when practical.
