Hazard analysis calculation techniques

Other computer models and analytical tools are used to predict how materials, systems, or personnel respond when exposed to fire conditions. Hazard-specific calculations are more widely used in the petrochemical industry, particularly as they apply to structural analysis and exposures to personnel. Explosion and vapor cloud hazard modeling has been addressed in other CCPS Guidelines (CCPS, 1994). Again, levels of sophistication range from hand calculations using closed-form equations to numerical techniques. 

For the most rigorous examination each event in the fault tree can be given a probability, allowing the total frequency of the final event to be calculated. This is the technique of hazard analysis or Hazan. 

Modern techniques oftenallowworkwithmuchsmalleramountsofmaterialthan was possible only a few years ago. When working with radioactive materials, full advantage should be taken of any efficient and effective procedure forusing less of the radioactive substance, not only at any given time, butoverthecourseofthe research. A carefully constructed written research plan and hazard analysis, in which the amounts of materials needed foreach procedure are calculated, will help the minimization process. 

Introduction Theprevious sections dealt with techniques for the identification of hazards and methods for calculating the effects of accidental releases of hazardous materials. This section addresses the methodologies available to analyze and estimate risk, which is a function of both the consequences of an incident and its frequency. The apphcation of these methodologies in most instances is not trivial. A significant allocation of resources is necessary. Therefore, a selection process or risk prioritization process is advised before considering a risk analysis study. 

In Chapter 1 structural design was outlined as a process of synthesis followed b an analysis of the likely hazards which might threaten the success of the propose structure. These hazards were split into three types, limit states, external randoi hazards, and human errors (Table 1.2). In this chapter, present calculatio techniques to deal with the first, the limit states, will be outlined and illustrate by the use of a simple worked example. However, in using these methods, cannot be emphasised too strongly that they deal with only part of the problen The designer must always remember that the possibility of human error and tl possibility of the occurrence of random hazards, such as fires and floods, are nc taken into account in these calculations. 

Often the success of a decontamination operation is expressed in terms of a cost-benefit analysis, i. e. a comparison of the expenses incurred during execution of the total procedure to the cumulative dose exposure (man-rems) which can be expected to be saved as a consequence of the reduced radiation levels. The problem with such an analysis, which is mainly in use in the USA, lies in the difficulty in translating radiation dose exposures saved into an equivalent amount of money. The result of such an analysis, therefore, depends highly on the equivalent assumed. On the basis of such cost-benefit analyses, substantial radiation exposure savings to the staff have been calculated, in particular when decontamination was carried out prior to inspection, repair or replacement work. As was shortly mentioned above, the initial concerns of the plant owners with regard to the costs, the potential success and the potential hazards of such an action have been largely dissipated and, at many plants, decontamination of particular systems has become a standard technique. However, as the measures taken for reduction of plant contamination buildup (see Sections 4.4.3. and 4.4.4.) will prove to be more and more successful in the future, the need of operational decontamination in the plants is expected to decrease. 

Mathematical Details of SAC-FEMA Technique The SAC-FEMA method (Pinto et al. 2004) is one of the popular methods to perform vulnerability analysis. In the SAC-FEMA approach, the seismic hazard P[IM = s] is defined in terms of spectral acceleration ordinates, calculated at the fundamental period of the structure. In this method the failure occurs when the maximum demand over the duration of the seismic excitation exceeds the correspraiding capacity. The seismic hazard is combined with the drift demand to define drift hazard as follows ... 

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