Major Hazards Screening

The order in which hazards analyses are carried out is usually determined by a preliminary consequence ranking i.e., those processes which have the potential for creating the most serious consequences are analyzed first. This can be done through the use of a Major Hazards Screening. In practice, the order in which hazards analyses are carried out is also affected by logistical issues such as the availability of up-to-date P IDs or of key personnel to serve as hazards analysis team members. 

During Phase I, the project team will conduct high-level hazards analyses, probably using some form of Major Hazards Screening. The team will be looking for killer problems that are so serious that the project will have to be canceled. The analysis will not consider details on design or the occupational safety and human factors issues discussed in the previous chapters. 

Fluorine plays another important role in display screen technology, albeit replacing another type of fluorine technology. F2 is often considered to be a dangerous harmful chemical (indeed it has been referred to as the Tyrannosaurus Rex of the elements [80]). However, its very reactivity ensures that it cannot persist in the environment, although its by-products may. The major hazards... 

The hazard analysis may identify many potential accident events. Some may be minor and some significant. For those minor accidents, one can stop here and no further analysis is required. If the hazard analysis indicates that the risk of an accident event is significant, then a detailed quantitative accident analysis will be performed for that accident. The hazard screening allows the major effort of safety analysis to be concentrated on those accidents that are significant. 

However, initially, preliminary hazard analysis is often done for hazard screening processes to assess a major event. This will help in developing an SMS and FSA. Therefore the discussion may be concluded by saying that no potential danger situation is liable for rejection however low the likelihood of its occurrence is. Also if any assumption is considered it must be recorded for further review. 

In the first step, a screening process will be applied to separate the major potential hazards these will be addressed in more detail. QRA techniques are used to evaluate the extent of the risk arising from hazards with the potential to cause major accidents, based on the prediction of the likelihood and magnitude of the event. This assessment will be based on engineering judgement and statistics of previous performance. Where necessary, risk reduction measures will be applied until the level of risk is acceptable. This of course is an emotive subject, since it implies placing a value on human life. 

A number of commercial expert systems have been applied to screen drug libraries. For instance, DEREK, TOPKAT, MultiCASE, and many other systems all have possibilities in this regard. However, it should be noted that for broad screening only compounds with toxicity associated with them can be identified, and hence these are very crude measures of hazard assessment. The use of expert systems to screen libraries is fraught with dangers, not least that no performance statistics are available for these systems being used for such an application. It is also highly probable that the vast majority of predic-... 

Defining positive as the absence of hazard. Using Clean Production Action s Green Screen, the ideal chemicals are defined as those that have low hazard for all relevant hazard endpoints as exemplified by Benchmark 4. While it is anticipated that the majority of chemicals will not ciurently reach Benchmark 4, it is stiU important to have a vision of what good (and... 

---