Process hazard analysis application

Process Hazards Analysis (PrHA) - The application of analytical methods to identify and evaluate process hazards to determine the adequacy or control. 

In 1993, the Center for Chemical Process Safety (CCPS) published Guidelines for Safe Automation of Chemical Processes (referred to henceforth as Safe Automation). Safe Automation provides guidelines for the application of automation systems used to control and shut down chemical and petrochemical processes. The popularity of one of the hazard and risk analysis methods presented in Safe Automation led to the publication of the 2001 Concept Series book from CCPS, Layer of Protection Analysis A Simplified Risk Assessment Approach. This method builds upon traditional process hazards analysis techniques. It uses a semiquantitative approach to define the required performance for each identified protective system. 

If a recommendation asks for a change in the process, the action must undergo a formal process hazard analysis (PHA) study, such as a HAZOP or other methodology, before implementation. This systematic and formal approach identifies and evaluates hazards associated with the proposed revisions. The study may uncover failure scenarios, adverse consequences, and obscure relationships that are not immediately apparent. The CCPS publication Hazard Evaluation Procedures i is an excellent guide to selection and proper application of PHA methodologies. 

Process Hazard Analysis (PHA) can be defined as the application of a systematic method to a process design in order to identify potential hazards and operating problems. It determines the causes and consequences of abnormal process conditions that arise from equipment failure, human error or other events. The goal is to determine whether opportunities exist to reduce the risks of the toll s hazards and then to implement warranted action items. The AJChE CCPS guideline Guidelines for Hazard Evaluation Procedures, Second Edition with Worked Examples is a good resource for fully detailed approaches to process hazard analysis. It provides an introduction to hazard evaluation as well as guidance on ... 

Once all what-if analysis questions have been asked and answered along with all completed HAZOP studies of system components, a final report should be written to document all findings and recommendations. In the chemical industry (in the United States), this report is normally referred to as a process hazard analysis. This report is required under both OSHA and EPA regulations for facilities that handle or contain certain chemical commodities at certain defined quantity thresholds. However, when HAZOP studies and what-if analyses are used in general industry application, documentation of the results can be included in a written report along with any other system safety analyses that may have been performed (as described in previous chapters). If the HAZOP and what-if exercises were conducted as standalone analyses, then a final written report should be... 

Crowl, D. A. and J. F. Louvar, Chemical Process Safety Fundamentals with Applications, 2nd ed., Prentice Hall, Englewood Cliffs, NJ, 2002. Dash, S. and V. Venkatasubramanian, Integrated Framework for Abnormal Event Management and Process Hazard Analysis, AIChE L, 49,124 (2003). 

To develop a safe design, it is necessary to first design and specify all equipment and systems in accordance with applicable codes and standards. Once the system is designed, a process safety shutdown system is specified to assure that potential hazards that can be detected by measuring process upsets are detected, and that appropriate safety actions (normally an automatic shutdown) are initiated. A hazards analysis is then normally undertaken to identify and mitigate potential hazards that could lead to fire, explosion, pollution, or injury to personnel and that cannot be detected as process upsets. Finally, a system of safety management is implemented to assure the system is operated and maintained in a safe manner by personnel who have received adequate training. 

A fault tree is a grapliic teclmique used to analyze complex systems. The objective is to spotlight conditions tliat cause a system to fail. Fault tree analysis attempts to describe how and why an accident or otlier undesirable event lias occurred. It may also be used to describe how and why an accident or otlier undesirable event could take place. Thus fault tree analysis finds wide application in hazard analysis and risk assessment of process and plant systems. ... 

While quality was formerly achieved by inspection of final products, it is accomplished now by prevention through controlling critical steps in the production processes along the agri-food chain. Hazard analysis critical control points (HACCP) represent a typical example of such a preventive approach. Although this concept was developed primarily to assure food safety, the basic principle is also applicable to assuring non-safety quality attributes such as color, flavor, and nutritional value. " This section translates the HACCP principles into a critical quality control point (CQP) concept that can be part of a system to assure food quality. 

Zatka, A. V., "Application of Thermal Analysis in Screening for Chemical Process Hazards," Thermochimica Acta, 28,7 (1979). 

The hydrocyclone process is applicable for processing hard and soft wheat flours, and perhaps even wholemeal flour.92 In addition to its versatility in processing different wheat classes, other advantages of the hydrocyclone process compared to the Martin process include an increased yield of gluten, lower water and energy requirements, and manageable levels of effluent. To ensure the food safety of wheat starch, quality programs in many companies dictate the implementation of hazard analysis and critical control points in the hydrocyclone process.24... 

HAZOP and What-If reviews are two of the most common petrochemical industry qualitative methods used to conduct process hazard analyses. Up to 80% of a company s process hazard analyses may consist of HAZOP and What-If reviews with the remainder 20% from Checklist, Fault Tree Analysis, Event Tree, Failure Mode and Effects Analysis, etc. An experienced review team can use the analysis to generate possible deviations from design, construction, modification, and operating intent that define potential consequences. These consequences can then be prevented or mitigated by the application of the appropriate safeguards. 

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