Offshore oil and gas platforms are well known for their compact geometry, high degree of congestion, limited ventilation and difficult escape routes. A small mishap under such conditions can quickly escalate into a catastrophe. Among all the accidental process-related events occurring offshore, fire is the most frequently reported. It is, therefore, necessary to study the behavior of fires and quantity the hazards posed by them in order to complete a detailed quantitative risk assessment. While there are many consequence models available to predict fire hazards-varying from point source models to highly complex computational fluid dynamic models—only a few have been validated for the unique conditions found offshore.
In this paper, we have considered fire consequence modeling as a suite of sub-models such as individual fire models, radiation model, overpressure model, smoke and toxicity models and human impact models. This comprehensive suite of models was then revised by making the following modifications: (i) fire models: existing fire models have been reviewed and the ones most suitable for offshore conditions were selected; (ii) overpressure impact model: a model has been developed to quantify the overpressure effects from fires to investigate the possible damage from the hot combustion gases released in highly confined compartments; (iii) radiation model: instead of a point/area model, a multipoint grid-based model has been adopted for better modeling and analysis of radiation heat flux consequences. A comparison of the performance of the revised models with the ones used in a commercial software package for offshore risk assessment was also carried out and is discussed in the paper. 相似文献
The results of the UN test O.1 for oxidizing solids are shown to be incorrect when specimens contain certain inertant additives, illustrated for the case of oxidizers in the ammonium nitrate fertilizer family. Test results for three different AN-based products containing inertants show that two of the three (including calcium ammonium nitrate, CAN, a long-known safer alternative to AN) would be misranked with the O.1 test. An analogy between the heat release rate of substances containing fire retardant (FR) chemicals is established and several ways by which FR behavior can be achieved are demonstrated. It is shown that the O.1 test implicitly adopts only one model of inertant action, and that chemicals which rely on a differing mode of inertant action are liable to be incorrectly treated. It is further shown that the physical basis of the O.1 test—an intimate mixture of finely-comminuted fuel and oxidizer—misrepresents the most common type of accidents involving oxidizers, and that such test results do not correspond to scenarios of a less extreme nature. The new O.3 test improves the analysis method, but does not resolve the problem of excessive commingling of fuel into oxidizer. It is recommended that the intermediate-scale arrangement used by the Bureau of Explosives be adopted for further development and standardization, in preference to the O.1 or O.3 test arrangements. 相似文献