Accident purpose

The purpose of hazard analysis and risk assessment ia the chemical process industry is to (/) characterize the hazards associated with a chemical facihty (2) determine how these hazards can result in an accident, and (J) determine the risk, ie, the probabiUty and the consequence of these hazards. The complete procedure is shown in Figure 1 (see also Industrial hygiene Plant safety). 

The Center for Chemical Process Safety (CCPS) was established in 1985 by the American Institute of Chemical Engineers (AICliE) for the express purpose of assisting the Chemical and Hydrocarbon Process Industries in avoiding or mitigating catastrophic chemical accidents. To achieve this goal, CCPS has focused its work in four areas ... 

The accident reporting procedure should be more than reporting of equipment damage for insurance purposes. The report should show appropriate action taken to prevent a recurrence. 

Sometimes the expected consequences of an accident alone may provide you with sufficient information for decision-making purposes. Conventionally, the form of these estimates will be dictated by the purpose (concern) of the study (safety, economics, etc.). Absolute consequence estimates are best estimates of the impacts of an accident and, like frequency estimates, may have considerable uncertainty. Table 4 contains examples of typical consequence estimates obtained from QRA. These examples point to the difficulty in comparing various safety and economic results on a common basis—there is no common denominator. 

In such emergencies, it is most important to know the local wind direchon at the accident site, so that the area that should be immediately evacuated can be determined. The next important factor is the wind speed, so that the travel hme to various areas can be determined, again primarily for evacuation purposes. Both of these can be estimated on-site by simple means such as watching the drift of cigarette smoke. It would be well to keep in mind that wind speeds are higher above ground and that wind direction is usually different. 

The fault tree identifies component failures that cause the top event. Systems ma be required to respond in different ways to different accidents, suggesting a general top event )r a general purpose fault tree that adapts to specific system configurations. This may result in ambi jity in the top event definition and difficulty in construction. It is better and easier to prec fy... 

Accident simulation Large-scale accidents normally cannot be staged for experimental purposes. It is impossible to put a building on fire in order to see how smoke spreads. In this case, numerical simulation is the sensible approach. 

Risk iuialysis of accidents serves a dual purpose. It estimates tlie probability tliat iui accident will occur and also assesses the severity of the consequences of an accident. Consequences may include dmnage to tlie surrounding enviromnent, financial loss, injury to life and/or deatli. This Part of the book (Part IV) is primarily concerned witli tlie metliods used to identify liazards and causes and consequences of accidents. Issues dealing witli healtli risks have been explored in die previous Part (III). Risk assessment of accidents provides an effective way to help ensure eidier diat a mishap will not occur or reduces the likelihood of an accident. The result of die risk assessment also allows concerned parties to take precautions to prevent an accident before it happens. 

Dedicated facilities are often cited for safety purposes, but this, too, is not a simple truth. Most accidents occur at intersections, and dedicated facilities make intersections far more complex. When the Netherlands allowed their moped riders to travel in the auto lanes instead of the bike lanes, the moped accident rate fell by an astounding 70 percent. The bicycle accident rate would be higher if bicyclists tried to ride at brisk speed m these separated bike lanes. The sub-lO-mph speeds that are considered polite in these countries largely allow bicyclists to compensate for the facilities shortcomings, at the expense of travel time. 

In recent years there has been a tendency to use a.c. in preference to d.c. for industrial purposes, but d.c. systems may still be operating in shipyards, steelworks and similar sites for motive power and also for mobile cranes, lighting and control equipment. The running rails and mountings of such systems are usually in close contact with the earth and severe leakages can be expected to occur, either accidently or eis a result of deterioration with age. 

When ammo is manufactured, an ammunition lot number is assigned in accordance with pertinent specifications. As an essential part of the marking, this lot number is stamped or marked on the item, size permitting, as well as on all packing containers. It is required for all purposes of record, including reports on condition, functioning, and accidents, in which the ammo is involved. To provide for the most uniform functioning, all of the components in any one lot are manufactured under as nearly identical conditions as practicable... 

A pyrotechnic mixture of sulphide/potassium chlorate/aluminium has led to regular detonations. This sulphide incandesces as soon as it is in contact with chloric acid. Mixtures of antimony trisuiphide with alkaline nitrates, which are probably used for pyrotechnic purposes, also lead to detonations. Bengal lights has been made with this mixture, which was used in small quantities in mixtures and no accidents were experienced. Finally, dichlorine oxide detonates in contact with this sulphide. 

When analysing these different lists one realises that the different sources do not agree with each other. So far as the NFPA reactivity code is concerned, codes 2 and 3 have been attributed to epoxides and ethers that are unsaturated. Their purpose is to inform the reader about dangerous polymerisation and not peroxidation risks. The accidents described below also involve compounds such as dibutyl ether that are not considered as dangerous in the regulations or NFPA Extracting a fatty substance and a floor wax with diethyl ether gives rise to a detonation. 

An accident can be defined as "an unplanned event or sequence of events that results in an undesirable consequence." For the purposes of this book, undesirable consequence is defined as an explosion or fire. 

The generic P and U list waste description involves two key factors. First, a P or U listing applies only if one of the listed chemicals is discarded unused. In other words, the P and U lists do not apply to manufacturing process wastes, as do the F and K lists. The P and U listings apply to unused chemicals that become wastes. Unused chemicals become wastes for a number of reasons. For example, some unused chemicals are spilled by accident. Others are intentionally discarded because they are off-specification and cannot serve the purpose for which they were originally produced. 

More important, however, is to consider the contributions—good and bad—which explosives have made to the history of mankind. Any real assessment of this must show that the benefits which explosives have produced far outweigh their misuse in military pursuits. The explosives technologist, who has usually seen and perhaps even experienced the effects of explosives, is the last to want war or to want his products to be used for warlike purposes. It is no accident that Nobel, who founded the modern explosives industry, also founded the Peace Prize associated with his name. In this book the writer has followed his instincts and given pride of place to commercial, beneficial applications of explosives. 

The purpose of a what-if analysis is to identify hazards, hazardous situations, or specific accident events that could produce an undesirable consequence. The what-if analysis is described in detail in Guidelines for Hazard Evaluation Procedures (CCPS, 1992). 

The primary purpose of LOPA is to determine whether there are sufficient layers of protection against a specific accident scenario. As illustrated in Figure 11-16, many types of protective layers are possible. Figure 11-16 does not include all possible layers of protection. A scenario may require one or many layers of protection, depending on the process complexity and potential severity of an accident. Note that for a given scenario only one layer must work successfully for the consequence to be prevented. Because no layer is perfectly effective, however, sufficient layers must be added to the process to reduce the risk to an acceptable level. 

The accident investigation report is written using the principles of technical documentation. Items 1-4 are objective and should not include the authors opinions. Items 5-7 appropriately contain the opinions of the authors (investigation team). This technical style allows readers to develop their own independent conclusions and recommendations. As a result of these criteria, the accident investigation report is a learning tool, which is the major purpose of the investigation. 

Another source of design information is the accident reports made after an accident. They give valuable information of the possible weaknesses that can occur in unit operations, while they are used for certain purposes. In the past many of the unit operations have shown their adverse characteristics. This information is mainly collected to accident reports and included to safety standards. Accident reports tell us for example ... 

The main purpose of this research is to design a protocol which provides companies in the chemical process industry with a better understanding of possible indicators of an accident, to enable them to further enhance their Safety Management Systems (SMS). 

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