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Combustion hazards from building materials

Stec A. A.

Materiały Budowlane

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2014

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nr 10

32--35

EN

Fire smoke has a highly variable composition which is dependent on several factors, including oxygen supply, heating rate, temperature and the chemical structure of the materials that are burning. One area that is particularly important is the determination of volatiles that can have a negative effect on the environment as well as posing a serious hazard to human health. Prediction of toxic fire hazard depends on two parameters: time-concentration profiles for major products. These depend on the fire growth curve and the yields of toxic products; toxicity of the products, based on estimates of doses likely to impair escape efficiency, cause incapacitation, or death. Toxic product yields depend on the material composition, and the fire conditions. The most significant differences in fire conditions arise between flaming and non-flaming combustion. The burning of an organic material, such as a polymer, is a complex process, in which volatile breakdown products react, to a greater or lesser extent, with oxygen, producing a cocktail of products. These range from the relatively harmless carbon dioxide (CO2) and water, to products of incomplete combustion, including carbon monoxide (CO), hydrogen cyanide (HCN), organoirritants etc. In addition, depending on the other elements present, halogen acids, oxides of nitrogen, and sulphur, may be formed. The fire toxicity of building materials were investigated under a range of fire conditions, oxidative pyrolysis (smouldering) and well-ventilated flaming to under-ventilated flaming. The yields of the major toxic products, carbon monoxide, hydrogen cyanide and irritant gases nitrogen dioxide, hydrogen chloride and hydrogen bromide together with polycyclic aromatic hydrocarbons are presented as a function of fire condition. The toxicities of the effluents, showing the contribution of individual toxic components, are compared using the fractional effective dose (FED) model and LC50, (the mass required per unit volume to generate a lethal atmosphere under specified conditions).

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Prediction of rockburst probability given seismic energy and factors defined by the expert method of hazard evaluation (MRG)

Kornowski J., Kurzeja J.

Acta Geophysica

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2012

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Vol. 60, no. 2

472-486

EN

In this paper we suggest that conditional estimator/predictor of rockburst probability (and rockburst hazard, PT(t)) can be approximated with the formula PT(t) = P₁(Θ₁) ••• PN(₁N) • PTdyn(t), where PTdyn(t) is a time-dependent probability of rockburst given only the predicted seismic energy parameters, while Pi(Θi) are amplifying coefficients due to local geologic and mining conditions, as defined by the Expert Method of (rockburst) Hazard Evaluation (MRG) known in the Polish mining industry. All the elements of the formula are (approximately) calculable (on-line) and the resulting PT value satisfies inequalities 0 ≤ PT(t) ≤ 1. As a result, the hazard space (0-1) can be always divided into smaller subspaces (e.g., 0-10⁻⁵, 10⁻⁵-10⁻⁴, 10⁻⁴-10⁻³, 10⁻³-1), possibly named with symbols (e.g., A, B, C, D, …) called "hazard states" - which saves the prediction users from worrying of probabilities. The estimator PT can be interpreted as a formal statement of (reformulated) Comprehensive Method of Rockburst State of Hazard Evaluation, well known in Polish mining industry. The estimator PT is natural, logically consistent and physically interpretable. Due to full formalization, it can be easily generalized, incorporating relevant information from other sources/methods.

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The Ranking of Explosives by Use of Material Indices as Proposed in the Temclev-Ex Method

Piotrowski T., Frączak M., Buczkowski D., Papliński A., Maranda A.

Central European Journal of Energetic Materials

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2006

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Vol. 3, nr 1-2

3-17

EN

The parametric system Temclev-Ex of fire and explosion hazard evaluation for devices and enterprises dealing with condensed explosives is presented. A brief description of the original Temclev method of evaluation and classification of the process hazard in chemical industry is given. The methodics of definition and estimation of the parametric indices characterising hazard level ensuing from constitutive properties of the reactive material is described. An exemplary evaluation of material indices for several explosives is made.