New hazards analysis

These four types of inadequate control actions are used in the new hazard analysis technique described in chapter 8. 

The most common form of inconsistency occurs when one or more process models is incomplete in terms of not defining appropriate behavior for all possible process states or all possible disturbances, including unhandled or incorrectly handled component failures. Of course, no models are complete in the absolute sense The goal is to make them complete enough that no safety constraints are violated when they are used. Criteria for completeness in this sense are presented in Safeware, and completeness analysis is integrated into the new hazard analysis method as described in chapter 9. 

STAMP provides a direction to take in creating these new hazard analysis and prevention techniques. Because in a system accident model everything starts from constraints, the new approach focuses on identifying the constraints required to maintain safety identifying the flaws in the control structure that can lead to an accident (inadequate enforcement of the safety constraints) and then designing a control structure, physical system and operating conditions that enforces the constraints. 

Technical Authority (ITA) recommended in the report of the Columbia Accident Investigation Board. The risk analysis itself is described in the chapter on the new hazard analysis technique called STPA (chapter 8). But the first step in the safety or risk analysis is the same as for technical systems to identify the system hazards to be avoided, to generate a set of requirements for the new management structure, and to design the control structure. 

As designed, this safety control structure looks strong and potentially effective. Unfortunately, it has not always worked the way it was supposed to work and the individual components have not always satisfied their responsibilities. Chapter 8 describes the use of the new hazard analysis technique, STPA, as well as other basic STAMP concepts in analyzing the potential risks in this structure. 

For every new tolling situation a process hazard analysis should be conducted using one of several acceptable methodologies in common use. The goal is to select a methodology appropriate to evaluate the hazards of the toll process in question. 

A PHA has heen performed for new facilities. The management of change documentation packages and referenced documents should indicate when a process hazard analysis was performed for the modification or new facility. The PSSR Team should verify all of the PHA recommendations have been implemented or otherwise resolved before the toll process can be judged ready to operate. 

For new facilities, the initial process hazard analysis (PHA) has been performed and recommendations have been resolved. ... 

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... 

After potential hazards have been identified, site access and hazard controls should be developed and put in place before work begins. This process of recognizing and evaluating new hazards and putting controls in place continues until the task or job analysis is complete. In addition, as mentioned earlier, as new information is discovered or becomes available, this should be immediately considered. If an amendment is in order, this should be completed and communicated to all involved. 

Our reaetion should inelude a new look at the unexpeeted work aetivity. One effeetive way to do this is through a job hazard analysis. Job hazard analysis was diseussed in detail in a previous ehapter, but for now, keep in mind that when the unexpeeted oeeurs you should reaet quiekly and get the whole team involved. Make sure to inelude the field supervisor and worker. 

Detailed guidanee on the eontent and applieation of proeess hazard analysis methodologies is available from the Ameriean Institute of ehemieal Engineers Center for Chemieal Proeess Safety, 345 E. 47th Street, New York, New York 10017, (212) 705-7319. Also, see the diseussion of various methods of proeess hazard analysis eontained in the Appendix to this publieation. 

Hazards analysis techniques fall in two broad categories. Some techniques focus on hazards control by assuring that the design is in compliance with a pre-existing standard practice. These techniques result from prior hazards analysis, industry standards and recommended practices, results of incident and accident evaluations or similar facilities. Other techniques are predictive in that they can be applied to new situations where such pre-existing standard practices do not exist. 

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. 

The above data should be useful for tlie planning to be accomplished by tlie local emergency planning committee and first responders, especially fire departments and HAZMAT teams. Both tlie hazards analysis (discussed in detail in Parts II and IV) and tlie development of emergency countermeasures should be facilitated by the availability of MSDS information. If significant new information regarding a chemical is discovered, revised material safely data sheets must be submitted. 

If the process is a new design, the experience requirement may be satisfied by bringing in a person from a sister plant or from a similar or precursor process. In addition, at least one member of the team must be knowledgeable in the hazard analysis methodology being used (see note at the end of Section 1.0). 

The update team must develop a new PrHA report to document the scope and approach of its analysis as well as any new hazards, scenarios, and action items. Justification must be provided for removing any scenarios from the original PrHA. The report should receive close scrutiny, both for compliance with the PSM Rule and for explanations of new action items. Guidance for reporting the PrHA results is given in Section 5.1. The updated report is submitted to management for review and approval, following the same procedure as an initial PrHA. 

Although risk analysis of new facilities is required by Ref. 39, the method of conducting the analysis is left quite open. The reference suggests fault hazard analysis, fault tree analysis, or sneak circuit analysis. Ref. 41 is an example of a thorough hazards evaluation and risk analysis for a new facility at Radford Army... 

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). 

Mosley et al. (2000) describe a "chemistry hazard analysis" approach, similar to a hazard and operability (HAZOP) study method applied at the early development stages of a new process. Deviations from an intended chemical reaction are identified using typical HAZOP guidewords. Examples of deviations and consequences developed using this approach are shown in Table 4.10. Analyzing the basic chemistry of a process, where chemical reactions are intended to occur, can help ensure the consequences of deviating from the intended reaction are understood. 

Following this page is a blank material technical sheet used to accumulate technical data on the materials used within the unit. It is not intended that new data be generated for all our chemicals just to fill in the blanks on the sheet. It is intended that data necessary to support the Process Hazard Analysis of this unit, the design, and the operation of the unit be consistent, accurate, and available. 

Once a new process is identified as feasible, it goes through a process hazard analysis (usually HAZOP) to evaluate issues such as reactive chemistry. 

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