BS ISO 29903-1:2020 pdf download.Comparison of toxic gas data from different tests Part 1: Guidance and requirements.
This document provides principles for characterizing the measured production of toxic gases from alaboratory fire test and provides bases for comparing the results between different types and scales ofsuch tests. It also includes consideration of the uncertainties in the gas determinations. The combineduncertainty is a key factor in the ability to establish similarity or diference of test results.
The sufficiency of the agreement between a bench-scale test and a real-scale test depends on theprecision needed in the fire hazard or risk assessment, which is not covered by this document.
This document defines the relevance and significance of toxic gas data from measurements in differentfire tests. With such a definition it is possible to provide generic guidance on how such data can becompared between different sizes and types of fire tests.
The combustion conditions represented by the fire test, other specific characteristics of the test and thetest specimen, the sampling strategy of the fire effluents, and the analysis technique for the toxic gasspecies are the most important factors when defining the significance of the toxic gas data.
This document is intended to serve as a tool for the
a) definition of the relevance and significance of toxic gas data from fire tests,
b) comparison of toxic gas data from fire tests of different scales and characteristics, and
c) prediction of toxic gas data from a large-scale test based on small-scale data or vice versa.
This document gives general guidance regarding comparison of toxic gas data between physical firemodels of different scales, but is principally developed for the gases listed in lSo 13571, i.e. carbondioxide (Co2), carbon monoxide (Co), hydrogen halides (HCl,HBr, HF), sulfur dioxide (SO2), hydrogencyanide (HCN), nitrogen oxides (NO, NO2), formaldehyde (CH20) and acrolein (C3H40).
This document is not applicable to characterization and comparisons of the toxicity of the effluentsfrom fire tests.
2Normative references
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document.For dated references, only the edition cited applies. Forundated references, the latest edition of the referenced document (including any amendments) applies.ISO 5725-1,Accuracy (trueness and precision) of measurement methods and results — Part 1: Generalprinciples and definitions
ISO 13344,Estimation of the lethal toxic potency of fire effluents
ISO 13571, Life-threatening components of fire — Guidelines for the estimation of time to compromisedtenability in fires
ISO 13943, Fire safety— Vocabulary
4Combustion conditions4.1General
The yields and nature of the fire effluent component from a fire test of any scale are determined by theinvolved fuels and the prevalent thermal and oxidative conditions in the current stage of the fire. Theseconditions also determine the burning rate of the products/materials and thus the rate of effluentgeneration. See ISo 16312-1.
During a fire test of a finished product, the combustion conditions are likely to change. These changesinclude the chemistry of the combustible item and the sufficiency of the ventilation.
Whether decomposition is flaming or non-flaming is a dominant factor in the production of toxic gases.The combustion conditions under which toxic gas data are developed shall be as close to equivalent aspossible between the physical fire models or test scales compared (see Clause 6).
NOTE1 A large change in the rate of combustion can affect the degree of oxidation of the emitted effuent.Smaller changes in combustion rate can have no significant effect.
NOTE 2 Fire stages and the corresponding combustion conditions are described in ISo 19706.4.2Thermal environment
The thermal boundary conditions in a test include the external applied heat flux and the heat flux fromany flaming combustion.Also of importance is the heat flux distribution among radiation, convection,and conduction.
The thermal environment sensed by thetestspecimen during combustion includes bothgas temperatureand the temperature of the sample material, as defined by the thermal boundary conditions.
4.3Ventilation
The oxygen availability (ventilation) in the physical fire models compared determines the combustionconditions. Comparison among different methods requires characterization of the ventilationconditions in order to assess the degree of similarity.BS ISO 29903-1 pdf download.
BS ISO 29903-1:2020 pdf download
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