ISO/TC 92/SC 3/WG 5 - Prediction of toxic effects of fire effluents

ISO/TR 13571-2:2016 describes the practical application of ISO 13571 as a tool to evaluate effects of fire effluents on people. The method of application, performance criteria and evaluation of the impact are explained and illustrated by two families of examples: application to real-scale tests (Annex A and Annex B) and application to Fire Safety Engineering (Annex C, D and E).

ISO 13344:2015 provides a means for estimating the lethal toxic potency of the fire effluent produced from a material while exposed to the specific combustion conditions of a physical fire model. The lethal toxic potency values are specifically related to the fire model selected, the exposure scenario and the material evaluated. Lethal toxic potency values associated with 30-min exposures of rats are predicted using calculations which employ combustion atmosphere analytical data for carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2) (vitiation) and, if present, hydrogen cyanide (HCN), hydrogen chloride (HCl), hydrogen bromide (HBr), hydrogen fluoride (HF), sulfur dioxide (SO2), nitrogen dioxide (NO2), acrolein and formaldehyde. The chemical composition of the test specimen may suggest additional combustion products to be quantified and included. If the fire effluent toxic potency cannot be attributed to the toxicants analysed, this is an indication that other toxicants or factors must be considered. ISO 13344:2015 is applicable to the estimation of the lethal toxic potency of fire effluent atmospheres produced from materials, products or assemblies under controlled laboratory conditions and should not be used in isolation to describe or appraise the toxic hazard or risk of materials, products or assemblies under actual fire conditions. However, results of this test may be used as elements of a fire hazard assessment that takes into account all of the factors which are pertinent to an assessment of the fire hazard of a particular end use; see ISO 19706. The intended use of fire safety-engineering calculations is for life-safety prediction for people and is most frequently for time intervals somewhat shorter than 30 min. This extrapolation across species and exposure intervals is outside the scope of ISO 13344:2015. ISO 13344:2015 does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of ISO 13344:2015 to establish appropriate safety and health practices.

ISO 13571:2012 is one of many tools available for use in fire safety engineering. It is intended to be used in conjunction with models for analysis of the initiation and development of fire, fire spread, smoke formation and movement, chemical species generation, transport and decay, and people movement, as well as fire detection and suppression. ISO 13571:2012 is to be used only within this context. ISO 13571:2012 is intended to address the consequences of human exposure to the life-threatening components of fire. The time-dependent concentrations of fire effluents and the thermal environment of a fire are determined by the rate of fire growth, the yields of the various fire gases produced from the involved fuels, the decay characteristics of those fire gases and the ventilation pattern. Once these are determined, the methodology presented in ISO 13571:2012 can be used for the estimation of the time at which individuals can be expected to experience compromised tenability. With care, this guidance can also be applied to estimation of the time limit for rescuing people who are immobile due to injury, medical condition, etc. ISO 13571:2012 establishes procedures to evaluate the life-threatening components of fire hazard analysis in terms of the status of exposed human subjects at discrete time intervals. It makes possible the estimation of the time at which occupants can experience compromised tenability. It enables estimation of a compromised tenability endpoint for each of the fire effluent components, with the most important endpoint being the earliest to occur. Although the concept of compromised tenability is consistent with the definition of incapacitation (see ISO 13943), the latter term is not used in ISO 13571:2012 due to its potentially broad interpretation to include many effects, including collapse and unconsciousness, that are not addressed. ISO 13571:2012 focuses specifically on compromised tenability as influenced by both physiological and behavioural responses resulting from exposure to a fire's life-threatening components. The life-threatening components addressed include fire-effluent toxicity, heat, and visual obscuration due to smoke. In cases where the effluent composition is available, the toxic gas model is to be used for assessment of fire-effluent toxicity. For those cases where the effluent composition is unknown, an additional mass-loss model using generic toxic potency values is provided.

ISO 13571:2007 is only one of many tools available for use in fire safety engineering. It is intended to be used in conjunction with models for analysis of the initiation and development of fire, fire spread, smoke formation and movement, chemical species generation, transport and decay and people movement, as well as fire detection and suppression. ISO 13571:2007 is to be used only within this context. ISO 13571:2007 is intended to address the consequences of human exposure to the life threat components of fire as occupants move through an enclosed structure. The time-dependent concentrations of fire effluents and the thermal environment of a fire are determined by the rate of fire growth, the yields of the various fire gases produced from the involved fuels, the decay characteristics of those fire gases and the ventilation pattern within the structure. Once these are determined, the methodology presented in ISO 13571:2007 can be used for the estimation of the available escape time. ISO 13571:2007 provides guidance on establishing the procedures to evaluate the life threat components of fire hazard analysis in terms of the status of exposed human subjects at discrete time intervals. It makes possible the determination of a tenability endpoint, at which time it is estimated that occupants are no longer able to take effective action to accomplish their own escape. The life threat components addressed include fire-effluent toxicity, heat and visual obscuration due to smoke. Two methods are presented for assessment of fire-effluent toxicity: the toxic-gas model and the mass-loss model. ISO 13571:2007 does not consider aspects such as the initial impact of visual obscuration due to smoke on factors affecting the time required for occupants to escape, the toxic effects of aerosols and particulates and any interactions with gaseous fire-effluent components and adverse health effects following exposure to fire atmospheres.

ISO 13344:2004 provides a means for estimating the lethal toxic potency of the fire effluents produced from a material while exposed to the specific combustion conditions of a physical fire model. The lethal toxic potency values are specifically related to the fire model selected, the exposure scenario and the material evaluated. Lethal toxic potency values associated with 30-min exposures of rats are predicted using calculations which employ combustion atmosphere analytical data for carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2) (vitiation) and, if present, hydrogen cyanide (HCN), hydrogen chloride (HCl), hydrogen bromide (HBr), hydrogen fluoride (HF), sulfur dioxide (SO2), nitrogen dioxide (NO2), acrolein and formaldehyde. If the fire effluent toxic potency cannot be attributed to the toxicants analysed, this is an indication that other toxicants or factors must be considered. ISO 13344:2004 is applicable to the estimation of the lethal toxic potency of fire effluent atmospheres produced from materials, products or assemblies under controlled laboratory conditions and should not be used in isolation to describe or appraise the toxic hazard or risk of materials, products or assemblies under actual fire conditions. However, results of this test may be used as elements of a fire hazard assessment that takes into account all of the factors, which are pertinent to an assessment of the fire hazard of a particular end use; see ISO/TS 19706. The intended use of fire safety-engineering calculations is for life-safety prediction for people and is most frequently for time intervals somewhat shorter than 30 min. This extrapolation across species and exposure intervals is outside the scope of ISO 13344:2004. ISO 13344:2004 does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of ISO 13344:2004 to establish appropriate safety and health practices.

ISO/TS 13571:2002 is only one of many tools available for use in fire safety engineering. It is intended to be used in conjunction with models for analysis of the initiation and development of fire, fire spread, smoke formation and movement, chemical species generation, transport and decay and people movement, as well as fire detection and suppression. ISO/TS 13571:2002 is to be used only within this context. ISO/TS 13571:2002 is intended to address the consequences of human exposure to the life threat components of fire as occupants move through an enclosed structure. The time-dependent concentrations of fire effluents and the thermal environment of a fire are determined by the rate of fire growth, the yields of the various fire gases produced from the involved fuels, the decay characteristics of those fire gases, and the ventilation pattern within the structure. Once these are determined, the methodology presented in ISO/TS 13571:2002 can be used for the estimation of the available escape time. ISO/TS 13571:2002 provides guidance on establishing the procedures to evaluate the life threat components of fire hazard analysis in terms of the status of exposed human subjects at discrete time intervals. It makes possible the determination of a tenability endpoint, at which time it is estimated that occupants will no longer be able to take effective action to accomplish their own escape. The life threat components addressed include fire effluent toxicity, heat and visual obscuration due to smoke. Two methods are presented for assessment of fire effluent toxicity, the toxic gas model and the mass loss model. Aspects such as the initial impact of visual obscuration due to smoke on factors affecting the time required for occupants to escape, the toxic effects of aerosols and particulates and any interactions with gaseous fire effluent components and adverse health effects following exposure to fire atmospheres are not considered in ISO/TS 13571:2002.

Provides a means for estimating the lethal toxic potency of the fire effluents produced from a material, while exposed to the specific combustion conditions of a laboratory fire model.

Reviews the progress of bioanalytical methodology, including the application of mathematical models which are available and may be used in the toxicological assessment of fire effluent atmospheres. Attention is also given to the application of such models as a means to minimize the use of laboratory animals in the testing of materials for fire effluent toxicity.