ISO/TC 92/SC 3/WG 2 - Fire chemistry

This document describes tools and gives guidance concerning interlaboratory trials related to fire effluent analyses. It explains the relative contributions from the physical fire model and analytical techniques to evaluate trueness and fidelity. It also explains the difficulties involved with the interpretation of round-robin data and with the evaluation of trueness in fire effluent analyses. This document complements ISO 12828-1, which deals with limits of quantification and detection and ISO 12828-2, which deals with interlaboratory validation of analytical methods. It is a toolbox useful in the framework of ISO/IEC 17025 assessment of any fire laboratory. Examples of existing standards where the information contained in this document can be used are the analytical chemical methods in ISO 19701[2], ISO 19702[3], ISO 5660-1[4], and the chemical measurements in the methods discussed in ISO/TR 16312-2, ISO 16405[6], ISO/TS 19021[7], or their application to fire toxicity assessment using ISO 13571[1] and ISO 13344[8].

This document provides definitions and equations for the calculation of toxic product yields and the fire conditions under which they have been derived in terms of equivalence ratio and combustion efficiency. Sample calculations for practical cases are provided. The methods are intended to be used to produce either instantaneous or averaged values for those experimental fires in which time-resolved data are available. This document is intended to provide guidance to fire researchers for — recording appropriate experimental fire data, — calculating average yields of gases and smoke in fire effluents in fire tests and fire-like combustion in reduced scale apparatus, — characterizing burning behaviour in experimental fires in terms of equivalence ratio and combustion efficiency using oxygen consumption and product generation data. This document does not provide guidance on the operating procedure of any particular piece of apparatus or interpretation of data obtained therein (e.g. toxicological significance of results).

ISO 12828-2:2016 describes tools and techniques for use in validating the analysis of fire gases when an analytical method is developed in a laboratory. It complements ISO 12828‑1, which deals with limits of quantification and detection. The tools and techniques described can be applied to the measurement of quantities, concentrations (molar and mass), volume fractions, and concentration or volume fraction versus time analyses. Fire effluents are often a complex matrix of chemical species, strongly dependent on the materials involved in the fire, but also dependent on fire scenario parameters (see ISO 19706). With such a wide variety of conditions, the analytical techniques available will differ in terms of the influence of the matrix on the methods and on the concentration ranges which can be measured. The analytical techniques available are likely to differ significantly in several respects, such as their sensitivity to the matrix and the range of concentrations/volume fractions which can be reliably measured. For these reasons, a unique reference analytical technique for every fire effluent of interest is, in practical terms, difficult or impossible to achieve. The tools in this document allow verification of the reliable measurement ranges and conditions for the analysis of fire effluents, thereby enabling a comparison among various analytical techniques. Examples of existing International Standards where the information contained in this document can be used are the analytical chemical methods in ISO 19701, ISO 19702, ISO 5660‑1, and the chemical measurements in the methods discussed in ISO/TR 16312‑2, ISO 16405, or their application to fire toxicity assessment using ISO 13571 and ISO 13344. NOTE 1 The variable "concentration" is used throughout this document, but it can be replaced in all places with "volume fraction" without altering the meaning. This does not apply to the Annexes. NOTE 2 Concentration can be calculated from volume fraction by multiplying by the density of the relevant gas at the relevant temperature and pressure.

ISO 19702:2015 specifies requirements and makes recommendations for sampling systems for use in small and large-scale fire tests, for the selection of parameters and use of the FTIR instrument itself and for collection and use of calibration spectra.

ISO 29904:2013 provides a guide to the generation of aerosol particles in fires, defines apparatus and procedures for the sampling and measurement of aerosols, and provides procedures for the interpretation and reporting of the data. It is intended to assist fire test designers and those making measurements at unwanted fires to choose and use appropriate methods for aerosol measurement for differing hazards to people and the environment. ISO 29904:2013 identifies the scope, applicability, and limitations of each method. The interpretation of the data from these measurements is strongly dependent on the end use of the data. Fire-generated aerosols may present a direct risk of restricting escape from fire by obscuring an exit route, or they may produce chronic health and environmental hazards from chemical compounds contained in the aerosol (for example, toxic chemicals like polycyclic aromatic hydrocarbons in soot or radionuclides form nuclear plant fires.) Aerosol particles may be inhaled to various depths in the lungs, depending on their size and density, or may be released into the environment and deposited on land and in watercourses. In particular, it addresses the following aspects of aerosol generation and measurement in fires: Adsorbed/dissolved gas or vapour phase species; Physical mechanisms involved in the transport of aerosols, dispersal in the fire plume, coagulation/agglomeration leading to variation in particle sizes and fractions, "thermophoresis" (main cause of soot deposition), "diffusiophoresis" and, sedimentation. The interactions between gases and vapours and aerosol: adsorption and removal of species from gas phase, transportation of adsorbed gases into the lungs; Sampling and measurement methods, including their principles of operation, method description, the data provided, and in each case their scope, field of application, advantages and disadvantages; Metrology of the measurement methods, and in the generation of "standard aerosols", and the related uncertainties; Physiological and environmental effects of aerosols insofar as these effects can be used to define the measurement method for specific applications; and Hazards of carbon particles present in the fire effluent as visible "smoke" through their size, morphology, chemical nature, and the nature of the effluent in which they are (or were) suspended. ISO 29904:2013 is not oriented toward the aerosols generated from controlled combustion. (e.g. incineration). However, much of the material in ISO 29904:2013 is common to such aerosols.

In ISO 12828-1:2007, limits of detection and limits of quantification are defined and calculated. It provides methods for determining suitable values for these two parameters for a specific analytical procedure and for a specific chemical species. It does not provide detailed guidance on methods of sampling and analysis of specific species which might be present in fire effluents. This guidance is contained in ISO 19701 and ISO 19702.

ISO 19703:2010 provides definitions and equations for the calculation of toxic product yields and the fire conditions under which they have been derived in terms of equivalence ratio and combustion efficiency. Sample calculations for practical cases are provided. The methods can be used to produce either instantaneous or averaged values for those experimental fires in which time-resolved data are available.

ISO 19703:2005 provides definitions and equations for the calculation of toxic product yields and the fire conditions under which they have been derived in terms of equivalence ratio and combustion efficiency. Sample calculations for practical cases are provided. The methods can be used to produce either instantaneous or averaged values for those experimental fires in which time-resolved data are available. ISO 19703:2005 is intended to provide guidance to fire researchers in the recording of appropriate experimental fire data, the calculation of average yields of gases and smoke in fire effluents in fire tests and fire-like combustion in reduced scale apparatus, and the characterization of burning behaviour in experimental fires in terms of equivalence ratio and combustion efficiency using oxygen consumption and product generation data. ISO 19703:2005 does not provide guidance on the operating procedure of any particular piece of apparatus or interpretation of data obtained therein (e.g. toxicological significance of results).

Specifies methods for the individual analysis of airborne concentrations of carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2), hydrogen cyanide (HCN), hydrogen chloride (HCl), hydrogen bromide (HBr), hydrogen fluoride (HF), oxides of nitrogen (NOx), and acrolein (CH2CHCHO) in fire effluents. Annex A gives examples of separation of permanent gases, annex B lists other gases of interest, and annex C describes a new method.