Major Hazards Analysis

Bayutt P., 2003. Major Hazards Analysis An improved method for Process Hazard Analysis, Process Safety Progress Vol. 22 (1), pp. 21-26. 

Baybutt, P., 2003. Major hazards analysis an improved method for process hazards analysis. Process Saf Prog. 

The major hazard analysis and control effort is concentrated in the design phase (or phases). The first and in many ways the most important hazard analysis is the preliminary hazard analysis (PHA). 

If a facility does not have a SEMP or SEMS program, one of the first steps in the development of such a program is to conduct a Major Hazards Analysis (MHA). The purpose of this analysis is to identify those areas of the facility that pose the greatest risk. This type of analysis, which will be qualitative in nature, will show, for example, that the risers present a greater risk than the platform s gas compressors. Therefore, the initial focus of the risk management program should be on the risers. An MHA can also be carried out in the early stages of a project. 

If this approach is followed, the first step is to conduct a high-level Major Hazards Analysis with a focus on high-consequence, as distictive as high-risk, hazards. 

The book has two parts one part is mainly related to hazard analysis methods applicable for all disciplines of engineering. The other part is based around recent lEC standards for life cycle analysis for safety instrumented systems (SlSs). The book covers all major hazard analysis methods and safety instrumentation applicable for all industrial plants. The book enjoys granted permission from lEC Switzerland to utilize some figures from their standards lEC 61508 and 61511 the premier international standards for E/E/PEs for SIS and life cycle methods (duly acknowledged). In view of the total coverage of the book, international society IChemE has included the book in their series of technical books. 

There are many well-established and proven ways of conducting a hazards analysis. Atone extreme as simple and relatively unstructured methods such as a Major Hazards Analysis. At the other end of the spectrum lie highly organized methods such as Hazard and Operability Analysis (HAZOP) and Layers of Protection Analysis (LOPA). 

A risk-based approach uses the systems shown in Figures 5.4 and 5.5 but prioritizes the work by levels of risk, starting with a Major Hazards Analysis. 

Hazard analysis (HAZAN) is a quantitative way of assessing the likelihood of failure. Other names associated with this technique are risk analysis, quantitative risk assessment (QRA), and probability risk assessment (PRA). Keltz [44] expressed the view that HAZAN is a selective technique while HAZOP can be readily applied to new design and major modification. Some limitations of HAZOP are its inability to detect every weakness in design such as in plant layout, or miss hazards due to leaks on lines that pass through or close to a unit but cany material that is not used on that unit. In any case, hazards should... 

More inclusive is Table 3.3.1 -3 which is appropriate at depth into the analysis. The major headings in this table address major hazardous subject areas,. iccideni mitigation, protection and repair. I or example, under the first major heading, "Storage of Raw Materials, Products, Intermediates," listed are confinement measures, release nicclumi.sms (valves), procedures for safe operation and limitations that must be observed for safety. 

You can quickly identify these plant sections by reviewing process flow diagrams and valving arrangements. Isolation points are defined by control valves or powered block valves that can be remotely activated. Process hazard analysis techniques help you identify the maximum credible accident scenarios. (Note that manual valves should not be considered reliable isolation points unless they are located to be accessible following a major accident. However, remotely-activated valves can only be considered reliable isolation points if there are adequate reliability engineering and maintenance programs in place.)... 

The project began with an extensive evaluation of 900 reported incidents involving failures of fixed pipework on chemical and major hazard plant. As part of the analysis a failure classification scheme was developed which considered the chief causes of failures, the possible prevention or recovery mechanism that could have prevented the failure and the underlying cause. The classification scheme is summarized in Figure 2.13. A typical event classification would be... 

The human factors audit was part of a hazard analysis which was used to recommend the degree of automation required in blowdown situations. The results of the human factors audit were mainly in terms of major errors which could affect blowdown success likelihood, and causal factors such as procedures, training, control room design, team communications, and aspects of hardware equipment. The major emphasis of the study was on improving the human interaction with the blowdown system, whether manual or automatic. Two specific platform scenarios were investigated. One was a significant gas release in the molecular sieve module (MSM) on a relatively new platform, and the other a release in the separator module (SM) on an older generation platform. 

A seismic stress analysis is not made as a routine procedure in the design of vessels for sites in the United Kingdom, except for nuclear installations, as the probability of an earthquake occurring of sufficient severity to cause significant damage is negligible. However, the possibility of earthquake damage may be considered if the site is a Major Hazards installation, see Chapter 9, Section 9.9. 

Cox, R. A., "An Overview of Hazard Analysis," in Proceedings of the International Symoisum on Prevention of Major Chemical Accidents, p. 1.37, Center for Chemical Process Safety/AIChE, New York, NY (1987). 

Identify Chemical Reactivity Hazards Process Risk Management Process Hazard Analysis Identification of Major Hazards... 

The concept of a safety case comes from the requirements of the European Union/European Community (EU/EC) Seveso Directive (82/501/EC) and, in particular, regulations that the United Kingdom and other member states used to implement that directive. United Kingdom regulations (Control of Industrial Major Accident Hazards [CIMAH], 1984 replaced by Control of Major Accident Hazards Involving Dangerous Substances [COMAH] in 1999) require that major hazardous facilities produce a safety report or safety case.64 The requirement for a safety case is initiated by a list of chemicals and a class of flammables. Like the hazard analysis approach (Section 8.1.2), experts identify the reactive hazards of the process if analysis shows that the proposed process is safe, it may be excluded from additional regulatory requirements. 

These major process hazards are to be determined by a formal process hazard analysis. The PHA determines which parameters are critical for the process (defined as Critical Operating Parameters - COP s)... 

Identify major hazards and inherent process risks (toxic, explosive). Systematic quantitative analysis of hazards and definition of measures to reduce them. 

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