Hazard analysis subjectivity

The book does not focus on occupational safety and health issues, although improved process safety can benefit each area. Detailed engineering designs are outside the scope of the book. This book intends to identify issues and concerns in batch reaction systems and provides 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 the book offers potential solutions to specific issues/concerns, ultimately the user needs to make the case for the solutions that best satisfy their company s requirements for a balance between risk reduction and cost. In many instances the book provides one or more sources of additional information on the subject which could be of value to the reader. 

The modified FMEA approach has been used by the API to develop RP14C. In this document ten different process components have been analyzed and a Safety Analysis Table (SAT) has been developed for each component. A sample SAT for a pressure vessel is shown in Table 14-4. The fact that Tables 14-3 and 14-4 are not identical is due to both the subjective natures of a Hazard Analysis and FMEA, and to the fact that RP14C is a consensus standard. However, although the rationale differs somewhat, the devices required are identical. (The gas make-up system in Table 14-4 is not really required by RP14C, as we shall see.)... 

This subject is addressed in the previous section of this chapter. Specific guidelines for performing hazards analysis are contained in API RP 14J. 

Hazard Analysis Report - Hazard and Operability Study (HAZOP), failure mode and effect analysis, quantitative fault tree analysis or what/if check list (sec Part IV for details in theses subjects)... 

The facility is subjected to a process hazard analysis commensurate to the level of hazard the facility represents (i.e., Checklist, PHA, HAZOP, What-If review, Event Tree, FMEA, etc.). The results of these analyses are fully understood and acknowledged by facility management. Where high risk events are identified, quantifiable risk estimation and effects of mitigation measures should be evaluated and applied if productive. 

Hazard and risk analysis is a vast subject by itself and is extensively covered in the literature [22]. In order to plan to avoid accidental hazards, the hazard potential must be evaluated. Many new methods and techniques have been developed to assess and evaluate potential hazards, employing chemical technology and reliability engineering. These can be deduced from Fault Tree Analysis or Failure Mode Analysis [23], In these techniques, the plant and process hazard potentials are foreseen and rectified as far as possible. Some techniques such as Hazards and operability (HAZOP) studies and Hazard Analysis (HAZAN) have recently been developed to deal with the assessment of hazard potentials [24]. It must be borne in mind that HAZOP and HAZAN studies should be properly viewed not as ends in themselves but as valuable contributors to the overall task of risk management... 

Whereas no quantitative consequence analysis is required by this legislation, the process hazards analysis must include a qualitative evaluation of the possible effects of failure of controls on employees. Details concerning development and implementation of programs for these subjects are available... 

The reader is urged to read Initiation of Explosives by Impact in Vol 7,135-R ff of this Encycl, Whereas that article dealt principally with the testing of expls, we shall want to include propints in the discussion. There is probably no subject in hazards analysis which is so actively studied as the role of impact, shock and thermal effects on the safety of expls and proplnts and which is as poorly understood. We have alluded to this incomplete state of theoretical development in the section of this article on Application of Computer Programming... 

Not every reaction should be subjected to full chemical hazard analysis, as some reactions, e.g., the hydrolysis of an ester in water, will have little... 

The sampling procedure used will obviously depend on the type of sample whether it is liquid or solid fresh, chilled or frozen and the type of container e.g. tinned, bottled). Other major problems are the frequency of sampling and the position on a production line from which a sample is taken. For example, when sampling from a food production line is carried out, an important consideration is whether or not the food has been subjected to sterilisation, or any form of pasteurisation after the point from which the sample was taken. This is considered further in the chapter on food microbiology under the concept of Hazard Analysis Critical Control Point (HACCP). Whatever the form of the sample, it should be collected in a sterile container using aseptic techniques, returned to the laboratory under conditions identical to those from which it was taken, and processed as rapidly as possible. 

The control of chemical hazards at SNL is documented in the Primary Hazard Screen and Hazard Analysis process for every project or facility. Work-specific technical work documents provide more detailed chemical hazard controls. Hazard control is based on the hierarchy of controls engineering controls first, administrative controls next, and personal protective controls last. ES H subject matter experts provide input on appropriate controls to chemical users and their management. 

Unfortunately, no tools exist for identifying hazards. It takes domain expertise and depends on subjective evaluation by those constructing the system. Chapter 13 in Safeware provides some common heuristics that may be helpful in the process. The good news is that identifying hazards is usually not a difficult process. The later steps in the hazard analysis process are where most of the mistakes and effort occurs. 

Based on my observation of the < clienfs > hazards analysis tracking system and my inquiries of knowledgeable plant personnel, it is my professional opinion that, as of this date, < client > has addressed and resolved, in accordance with applicable standards and good engineering practices, every condition that is ranked in any of the above-referenced hazards analyses as an A- or B-level risk. It is also my professional opinion that, as of this date, < client > is addressing, and has a timetable for resolution, of every condition that is ranked in the subject analyses. 

An accident occurring in an area that has been subject to a hazards analysis and for which the analysis generated a finding, but the follow-up was inadequate or tardy. This situation could generate a willful finding from an agency. 

Details of statistical analyses for potential toxicities that should be explicitly considered for all products and AEs of special interest Aiialyses for these events will in general be more comprehensive than for standard safety parameters. These analyses may include subject-year adjusted rates, Cox proportional hazards analysis of time to first event, and Kaplan-Meier curves. Detailed descriptions of the models would typically be provided. For example, if Cox proportional hazards analysis is specified, a detailed description of the model(s) that will be used should be provided. This would generally include study as a stratification factor, covariates, and model selection techniques. More advanced methods, such as multiple events models or competing risk analyses, should be described if used (as appropriate). It is recommended that graphical methods also be employed, for example, forest plot and risk-over-time plot (Xia et al., 2011). 

Replacing a subject matter expert (SME)/core competency [e.g., relief sizing, risk assessment, mechanical integrity, incident investigation, process hazard analysis (PHA), or hazard identification... 

To be effective, safety professionals must understand hazards, risks, the relationship between hazards and risks, and hazards analysis and risk assessment techniques. In the use of hazard analysis and risk assessment matrices, judgments of incident probability and consequence will often be made on a subjective basis. And such systems can be made to work. They should be considered more art than science. 

Why should that history be relevant It indicates that where subjective judgments prevail at the outset, tittle is gained in making laborious computations as the hazard analysis proceeds. 

Learned speculations are to be made on the consequences of an occurrence the number of fatalities, injuries, or illnesses the value of property or equipment damaged the time for which productivity will be lost and the extent of environmental damage. Historical data can be of great value as a baseline. On a subjective basis, the goal would be to decide on the worst credible consequences should an incident occur, not the worst conceivable consequence. When the severity of consequence is determined, a hazard analysis will have been completed. 

To properly communicate with decision makers, a risk ranking system should be adopted so that priorities can be established. Since the hazard analysis and risk assessment exercise is subjective, the risk ranking system would also be subjective. 

Plan the work carefully. At the beginning of an extended project, formally analyze the proposed program for possible hazards and consider the consequences of possible failures or errors. Ask a colleague to review the hazard analysis with you. Being too close to a subject often leads to overlooking potential problems. Unfortunately, even with the best plans, eventualities will exist which no one thinks of, and these are just the ones which may result in accidents. 

Although system safety, as a separate discipline, has existed since the early 1900s, it is still subject to the ever-changing hazard reduction needs of modern-day industry. Its techniques and methods undergo constant modification and tailoring depending on a specific hazard analysis requirement or set of requirements. 

Recent developments take the risk assessment subject to a higher level within the practice of safety. By formalizing the hazard analysis and risk assessment process, a better appreciation of the significance of individual risks is achieved. As risks levels are categorized and prioritized, more intelligent decisions can be made with respect to their elimination or reduction. For the hazard analysis and risk assessment process, it is necessary to arrive at definitions of hazards, hazards analyses, risks, and risk assessments. 

The excerpt above is all that is said in the standard about hazard analysis and risk assessment. The subject is addressed further in Annex A which is informative. However, the intent of the hazard analysis and risk assessment provision is amplified in the shall provision Contained in Section 4.4.7, Management of Change ... 

Subject to the rules and procedures set forth in 29 CFR 1926.59(i) (1) through (12), employees and their designated representatives shall have access to trade secret information contained within the process hazard analysis and other documents required to be developed by this standard. 

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