Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
ISO 26367-3:2022 — Guidelines for Assessing the Adverse Environmental Impact of Fire Effluents — Part 3: Sampling and Analysis
Detailed sampling and analysis methods for environmentally significant fire effluents
1. Sampling Techniques for Fire Effluents Across Environmental Phases
ISO 26367-3:2022 provides detailed requirements for the sampling and analysis of fire effluents that have the potential to cause environmental contamination. Building on the framework established in Parts 1 and 2, this standard addresses the practical execution of environmental sampling across gas, liquid, and solid phases.
Sampling of fire effluents for environmental assessment differs fundamentally from life-threatening fire sampling. Environmental fires are often larger and less confined, with plumes extending for kilometres. This provides greater logistical opportunity for sampling but requires careful consideration of spatial and temporal variability.
Fire plume sampling: Direct air emission sampling can only be performed while the fire is ongoing. Airborne sampling from aircraft has been documented but relating point samples to ground deposition remains challenging. The standard references ISO 19701 and ISO 19702 for fire gas analysis methods, noting that these techniques were developed for higher concentrations and users should verify limits of quantification when applying them to environmental assessments.
| Phase | Sampling Method | Key Reference Standards |
|---|---|---|
| Gas / Vapour | Extractive continuous, open-path optical, grab sampling | ISO 19701, ISO 19702, ISO 9359 |
| Liquid | Surface water grab, groundwater monitoring wells, waste water | ISO 5667-1, -6, -10, -11 |
| Solid | Soil cores, sediment grabs, plant/crop sampling | ISO 10381-1, -2, -5; ISO 5667-12 |
2. Analytical Methods for Key Pollutants
The standard provides a comprehensive catalogue of analytical methods organised by pollutant group and environmental phase. This enables environmental professionals to select the most appropriate techniques for their specific assessment needs.
Gases and vapours: Halogenated acids (HX), NOx, and SOx are analysed using wet chemical methods (ISO 19701) or extractive FTIR (ISO 19702). Open-path FTIR has been successfully applied in wildland fire monitoring, including trace gas measurements from Australian forest fires. VOCs are sampled using sorbent tubes with thermal desorption and GC analysis (ISO 16017 series).
Liquid phase: PAHs in water are analysed by HPLC with fluorescence detection (ISO 17993 for 15 PAHs) or GC-MS (ISO 28540 for 16 PAHs). PCDD/PCDF analysis in water uses HRGC/HRMS (ISO 18073). PFOS and PFOA in drinking and surface water are determined by HPLC-MS/MS (ISO 25101).
When brominated flame retardants may be present in the fuel load, analysis must include polybrominated dibenzodioxins and furans (PBDD/PBDF). Although standardised methods for these compounds are not yet established, the same basic analytical approach used for chlorinated analogues applies.
Solid phase: Soil analysis for PAHs uses GC-MS (ISO 18287) or GC-MS/HPLC (ISO 13859). Dioxins and furans in soil are analysed by GC/HRMS (ISO 13914). Metals are determined using XRF screening (ISO 13196 for field use, ISO 18227 for laboratory) or ICP-MS after aqua regia digestion (ISO 11466).
3. Engineering Design Insights: Method Validation and Quality Assurance
ISO 26367-3 places strong emphasis on method validation and measurement uncertainty. All sampling and analysis must use validated methods, and a quantification of measurement uncertainty from the complete process—from sampling through to final analysis—should be made whenever possible.
Key practical considerations for field implementation:
- Background concentrations must be established in all cases as a basis for pollution level assessment. ISO 19258 provides guidance for soil background determination.
- Plant and farm product sampling can provide early indicators of environmental impact through bioaccumulation. Milk and eggs are particularly useful for delayed sampling as contaminant transfer times to these products are longer than to plants.
- Sample preservation is phase-dependent: Gas samples require storage at low temperature; liquid samples follow ISO 5667-3 preservation protocols; solid samples are stored per ISO 18512 (soil) or ISO 5667-15 (sludge and sediment).
- Atmospheric dispersion models may be used to determine the most relevant zones for soil sampling, integrating wind direction and intensity data for the entire fire duration.
Asbestos fibres in fire debris from building fires require specialised analysis using the ISO 22262 series (quantitative analysis in bulk materials) and ISO 10312/ISO 13794 for airborne fibre determination. This is particularly important when older buildings constructed with asbestos-containing materials are involved.
FAQ 1: Can air sampling be performed after the fire has been extinguished?
Direct air sampling of fire emissions can only be conducted while the fire is ongoing. However, analysis of fire residues and deposited materials can continue long after extinguishment, providing valuable data on pollutant types and concentrations.
Direct air sampling of fire emissions can only be conducted while the fire is ongoing. However, analysis of fire residues and deposited materials can continue long after extinguishment, providing valuable data on pollutant types and concentrations.
FAQ 2: What is the difference between extractive and open-path measurement?
Extractive sampling physically collects a sample for laboratory analysis or continuous monitoring. Open-path measurement directs a light beam (e.g., FTIR) across the effluent in situ, providing real-time concentration data without sample collection.
Extractive sampling physically collects a sample for laboratory analysis or continuous monitoring. Open-path measurement directs a light beam (e.g., FTIR) across the effluent in situ, providing real-time concentration data without sample collection.
FAQ 3: How should plant samples be collected for fire impact assessment?
Plants should be sampled in their vegetative state, avoiding water stress periods, and separated from soil immediately. Sample mass must be measured during collection, and transport conditions must prevent crushing or moisture loss.
Plants should be sampled in their vegetative state, avoiding water stress periods, and separated from soil immediately. Sample mass must be measured during collection, and transport conditions must prevent crushing or moisture loss.
FAQ 4: Which analytical method is preferred for PFAS analysis in water?
ISO 25101 covers PFOS and PFOA in drinking and surface water using HPLC-MS/MS. For a broader spectrum of 24 PFAS analytes, EPA Method 537 or ASTM D7979 are recommended for groundwater, surface water, and wastewater.
ISO 25101 covers PFOS and PFOA in drinking and surface water using HPLC-MS/MS. For a broader spectrum of 24 PFAS analytes, EPA Method 537 or ASTM D7979 are recommended for groundwater, surface water, and wastewater.
