Process Safety Hazards Risk

Our approaches to process safety metrics will be analogous to those that might be used to assess occupational exposure risk. One can also use different indices that have been developed as metrics for estimating and ranking the safety of a given process or chemical reaction. These include indices such as the Dow fire and explosion index [44], the Stoessel index [46] for hazard assessment and classification of chemical reactions, the Inherent safety index, the prototype index for inherent safety, and others [47, 48]. 

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Listed in Table 2.1 are the essential elements of managing chemical reactivity hazards, as described in Sections 4.1 through 4.10 of this publication. They are mapped to comparable elements in three other, broader process safety and risk management systems ... 

In many cases sulfuric acid is present at the user s site as part of a manufacturing process. The hazard risk is then generally small and under control nevertheless, all operators or company health and safety committees should periodically reexamine their acid handling systems to ensure that all that can be done to prevent dangerous situations occurring is in fact being done. 

Environmental policies Security procedures Insurance programs Finance and purchasing procedures Plant closing policy Employee manuals Hazardous materials plan Process safety assessment Risk management plan Capital improvement program Mutual aid agreements... 

Government regulations reqmre hazard and risk analysis as part of process safety management (PSM) programs. These are part of the process safety programs of many chemical process facilities. 

Process Safety Analysis This part treats the analysis of a process or project from the standpoint of hazards, risks, procedures for making potential damage estimates, and project reviews and audits. It can be helpful to management in assessing risks in a project. It consists of the following ... 

The book does not focus on occupational safety and health issues, although improved process safety can benefit these areas. Detailed engineering designs are outside the scope of this work. This book intends to identify issues and concerns in batch reaction systems and provide potential solutions to address these concerns. This should be of value to process design engineers, operators, maintenance personnel, as well as members of process hazards analysis teams. While this book offers potential solutions to specific issues/concerns, ultimately the user needs to make the case for the solutions that provide a balance between risk... 

Process risk management Industrial hygiene risks should be periodically reviewed as are process safety risks. Some of the process hazard assessment techniques used for PSM can be expanded to include consideration of industrial hygiene issues... 

Banks, W., Wells, J. E. (1992). A Probabilistic Risk Assessment Using Human Reliability Analysis Methods. In Proceedings of the International Conference on Hazard Identification and Risk Analysis, Human Factors, and Human Reliability in Process Safety. New York American Institute of Chemical Engineers, CCPS. 

The Center for Chemical Process Safety s projects fall into a number of general topic areas that comprise a comprehensive program. These topic areas include identification of hazards and analysis of risks, prevention and mitigation of the hazards identified, and better definition of areas affected by a release of hazardous materials. This book is the latest in the series dealing with hazard identification and risk analysis. 

Safety. The MR is much safer than the MASR. (1) The reaction zone contains a much smaller amount of the reaction mixture (hazardous material), which always enhances process safety. (2) In case of pump failure, the reaction automatically stops since the liquid falls down from the reaction zone. (3) There is no need to filter the monolithic catalyst after the reaction has been completed. Filtration of the fine catalysts particles used in slurry reactors is a troublesome and time-consuming operation. Moreover, metallic catalysts used in fine chemicals manufacture are pyrophoric, which makes this operation risky. In a slurry reactor there is a risk of thermal runaways. (4) If the cooling capacity is insufficient (e.g. by a mechanical failure) a temperature increase can lead to an increase in reaction, and thus heat generation rate. 

Opschoor, G., R. O. M. van Loo, and H. J. Pasman. "Methods for Calculation of Damage Resulting From Physical Effects of the Accidental Release of Dangerous Materials." International Conference on Hazard Identification, Risk Analysis, Human Factors and Human Rehabihty in Process Safety, January 15-17, 1992. 

These process safety management systems help ensure that facilities are designed, constructed, operated, and maintained with appropriate controls in place to prevent serious accidents. However, despite these precautions, buildings close to hazardous process plants have presented serious risks to the people who work in them. This observation is prompted by the fact that some buildings, because of their design and construction, have collapsed when subjected to comparatively moderate accidental explosions, with serious injury or fatality to the occupants. Conversely, experience indicates that personnel located outdoors and away from such buildings, if subjected to the same blast, may have a lower likelihood of serious injury or fatality. 

One of the most important elements of the PSM Rule is the process hazard analysis (PrHA). It requires the systematic identification of hazards and related accident scenarios. The PSM Rule allows the use of different analysis methods, but the selected method must be based on the process being analyzed. The PSM Rule specifies that PrHAs must be completed as soon as possible within a 5-year period. However, one-fourth of the PrHAs must have been completed by May 26, 1994, with an additional one-fourth completed each succeeding year. The highest risk processes were to be done first. A schedule for PrHAs must be established at the outset of a process safety management (PSM) program to give priority to the highest risk processes. PrHAs must be reviewed and updated at least every 5 years. 

Safety, hazard, and risk are frequently-used terms in chemical process safety. Their definitions are... 

In addition to an overview of government regulations, the book introduces the resources of the AICHE Center for Chemical Process Safety library. Guidelines are offered for hazard identification and risk assessment. The book concludes with case histories drawn directly from the authors experience in the field. 

GENERAL References AICHE/CCI S Guidelines for Chemical Process Quantitative Risk Analysis, 2d ed., American Institute of Chemical Engineers, New York, 2000. AICHE/CCPS, Guidelines for Hazards Evaluation Procedures, 2d ed., American Institute of Chemical Engineers, New York, 1992. Crowl and Louver, Chemical Process Safety Fundamentals with Applications, 2d ed., Prentice-Hall, Englewood Cliffs, N.J., 2002. Mannan, Lees Loss Prevention in the Process Industries, 3d ed., Elsevier, Amsterdam. 

FIG. 23-1 The hazard identification and risk assessment procedure. [Guidelines for Hazards Evaluation Procedures, Center for Chemical Process Safety (CCPS) of the American Institute of Chemical Engineers (AIChE) copyright 1985 AICHE and reproduced with permission. ]... 

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