BS ISO 19706:2011 pdf download
BS ISO 19706:2011 pdf download.Guidelines for assessing the fire threat to people.
7.1.5 Optical density of smoke
The obscuration of smoke over a chosen distance is obtained by measuring the degree of interruption of a light beam across a known path length. The scattering by an aerosol is wavelength-dependent, so it is necessary to correct the result for the response of the human eye A relationship exists between mass density and optical density of fire efflueni
NOTE See Reference (15j.
7.1.6 Heat
The rate of heat release can be measured using oxygen-consumption calorimetry (preferable) or by
measuring the temperature uicrease in the surroundings,
7.1.7 Radiant flux
A calibrated radiometer can measure the energy transmitted radiatively from the burning specimen. The value depends strongly on the size of the burning test specimen, the lurrwnosity of the flame and the location of the instrument relative to the flame.
7.1.8 Dose-response curve
If labOratory animals are to be used to obtain ECo information, they should be exposed to varyrng concentrations of effluent.
NOTE See ISO 13344
7.2 Effluent potency
7.2.1 Living organisms provide the most direct relationships between exposure to fire effluent and the possible effects from the exposure, However, most information is now generated using chemical and physical measurement of the effluent, combined with information deduced from prior human and laboratory-animal exposures. This International Standard provides guidelines for obtaining information with and without the use 01 laboratory animals.
7.2.2 Laboratory animals provide a direct measure of the effect of a single effluent component or a combination of components. They also integrate the effect of total fire effluent. It is necessary to relate the quantitative response of the selected animal species to the equrvalent response in people. For the lethal and incapacitating effects of some effluent components, there are toxicological conventions and data for audi relationships. For sub-lethal effects from some components, these relationships might be too uncertain or might not exist. There is some variability among animals of a given species, which it is necessary to include in the assessment of experimental uncertainty.
7.2.3 In many cases, conducting animal testing can be impractical.
7.2.3.1 Non-vertebrate bioassay is not yet applicable to the complex mixtures of components found in fire effluents due to the yet-unknown pathological mechanisms of the Individual and combined effluent components.
7.2.3.2 Equations have been deflved that relate the exposure to effluent components to lethal effects in rats and Incapacitating effects in people (ISO 13344, ISO 13571:2007). These equations are empirically derived front studies involving laboratory animals andiom accidental exposures of people. The only input to these equations Is derived from chemical and physical measurements of the effluent components. Thus. components that have not previously been identified as important are oveilooked, and the resulting determination of effluent effects contains an unrecognized uncertainty of unknown ma’iitude. Nonetheless. the contributions of a small set of toxic gases have been shown to estimate rat lethality within about 20 % for a wide variety of materials and products. Since physical incapacitation of rats occurs at effluent exposures of one half of those that cause death (again for a wide variety of materials and products), it Is inferred that rat physical incapacltation can be attributed to a small set of toxic gases. There is an empirical relationship between the exposure to fire effluent that is lethal to rats and the exposure that incapacitates especially smoke-sensitive people.
NOTE 1 For the majonty of products composed of commonly used materials and additives, the toxic potency to humans of combustion product mixtures can be evaluated adequately on the basis of data obtaIned by chemical analysis. For novel materials or additives, research Incorporating some limited animal exposures is Ueiy to be necessary for the evaluation of the combustion toxCty.
NOTE 2 To the extent that unusual toxic phenomena are observed during the bioassay, add ibonal research into the cause can be required. To date, such situations have been very rarety encowitered
7.3 Large-scale fire tests
7.3.1 Fire tests of a complete construction, Interior finish or furnishing product provide the best evaluation of the contribution of that product to a fire.
7.3.2 Each fire stage can be investigated using instrumental andIor animal measurements. The effects of the surrounding air flow conditions and compartment geometry can be investigated
7.3.3 Such tests are expensive, require specialized expertise and facilities to perform, and are time- consuming to cover the effects of different compartment and fire conditions on effluent ymid arid natse,
7.3.4 Measurements beyond those of the effluent components are necessary to relate the measured mass or concentration of the components to the yields of those components.
