Preliminary Hazard Analysis and

Contracts were awarded in March 2000, and preliminary EDPs were drafted by the technology providers in June 2000. Each EDP includes drawings and documentation, a preliminary hazards analysis, and projected life-cycle costs and schedules for the technology package to be implemented at a particular site. The final EDPs were released in December 2000. Experimental tests to support the EDPs were begun in June 2000, but some had not been completed when this report was prepared. Einal reports are expected to be published in mid-2001. 

Medium-risk facilities normally require at least a preliminary hazard analysis and some user involvement. 

Preliminary drawings or sketches may be adequate to prepare a preliminary hazard list. More detailed drawings are required for a preliminary hazard analysis, and even more detail is required for subsystem and system hazard analyses. Analytical trees, copies of maintenance and operating procedures (if available), and site maps may also be helpful. 

Prior hazard analyses (for example, preliminary hazard list, preliminary hazard analysis, and failure mode and effects analysis) should also be... 

The second and more common hardware FMEA examines actual system assemblies, subassemblies, individual components, and other related system hardware. This analysis should also be performed at the earliest possible phase in the product or system life cycle. Just as subsystems can fail with potentially disastrous effects, so can the individual hardware and components that make up those subsystems. As with the functional FMEA, the hardware FMEA evaluates the reliability of the system design. It attempts to identify single-point failures, as well as all other potential failures, within a system that could possibly result in failure of that system. Because the FMEA can accurately identify critical failure items within a system, it can also be useful in the development of the preliminary hazard analysis and the operating and support hazard analysis (Stephenson 1991). It should be noted that FMEA use in the development of the O SHA might be somewhat limited, depending on the system, because the FMEA does not typically consider the ergonomic element. Other possible disadvantages of the FMEA include its purposefiil omission of multiple-failure analysis within a system, as well as its failure to evaluate any operational interface. Also, in order to properly quantify the results, a FMEA requires consideration and evaluation of any known component failure rates and/or other similar data. These data often prove difficult to locate, obtain, and verify (Stephenson 1991). 

Concept Analysis of the Technical Plant after Planning. Preliminary hazard analysis and system structure analysis are intended to facilitate safety evaluation of the planned installation from the basic concept. Comprehensiveness of observation depends on the danger level of the installation. After concluding this work, basic changes in the technical procedure frequently become necessary and must be incorporated into the planning. 

Due to the need to check all safety measures, this part of the system analysis can become very voluminous. The method becomes difficult due to the constant change from the overall review of the plant to the review of individual components. For this reason it is important, in the case of major systems, to place preliminary hazard analysis and system structure analysis ahead of the evaluation of the planning concept. The advantages of this work plan are the following ... 

R. H. Perry, Preliminary Hazard Analysis and Risk Assessment for Wood Centre Development,... 

Introductory Information The analyst should provide basic information in this section of the report which describes the purpose and scope of the FMEA along with any limitations imposed on the analysis as a result (i.e., items not specifically within the scope of the analysis). The scope will also identify the type of FMEA (i.t., functional or hardware). Also included in the introduction section is an explanation of the methodology used to perform the analysis such as, but not limited to drawing reviews, examination of previous analyses (if applicable), evaluation of lessons learned, use of Preliminary Hazard List and/or Preliminary Hazard Analysis, and so on. Finally, any preestablished ground rules that may have been agreed upon should be provided here. Such ground rules typically limit or further narrow the scope of the FMEA, or just a portion of it, and should therefore be explained in the introductory pages of the report. 

As a practical matter, having knowledge of three risk assessment concepts will be sufficient to address most, but not all, risk situations. They are Preliminary Hazard Analysis and Risk... 

Systems Hazard Analysis (SHA) is a qualitative method combining aspects of preliminary hazard analysis and failure-mode and effect analysis (Firenze 1973). Its emphasis is on work-tasks performed in various operational procedures. SHA adds two important pieces of information to those methods previously discussed the standards or regulations violated and the relevant subsystem. It chooses a task activity or a dynamic event as the focal point of the analysis rather than a more static component. As with the other methods, an analyst with detailed knowledge of the system is required. 

A critical assembly is a split bed on which fissionable material used to mock up up a separated reactor core that is stacked half on each half. One half is on roller guides so that the two halves may be quickly pulled apart if the neutron multiplication gets too high. Use the Preliminary Hazards Analysis method described in section 3,2.1 to identify the possible accidents that may occur and the qualitative probabilities and consequences. List the initiators in a matrix to systematically investigate the whole process. Don t forget human error. 

What if Approaches Hazind and Operability (HAZOP) Studies Preliminary Hazard Analysis (PLHA) Process Hazard Analysis (PHA)... 

If several processes require PrHAs, the PrHAs must be prioritized. A preliminary hazard analysis (PHA) may be used to determine and document the priority order for conducting PrHAs. At a minimum, the PSM Rule requires the prioritization to consider the potential severity of a chemical release, the number of potentially affected employees, and the operating history of the process, including the frequency of past chemical releases and the age of the process. 

Partial what-if analyses for the two example processes described in Section 4.0 are shown in Tables 4.9 and 4.10. Although for actual, more complex analyses, the what-if tables for each line or vessel would be separate, for these examples, a single table was developed. A preliminary hazard analysis (PHA) would identify that the intrinsic hazards associated with HF are its reactivity (including reactivity with water, by solution), corrosivity (including carbon steel, if wet), toxicity via inhalation and skin contact, and environmental toxicity. The N2 supply system pressure is not considered in this example. The specific effects of loss of containment could be explicitly stated in the "loss of HF containment" scenarios identified. Similarly, the effects of loss of chlorine containment, including the reactivity and toxicity of chlorine, could be specified for the second example. 

A designer, as part of his facility design analysis, should perform a hazards analysis or risk assessment of the various processes which will be conducted within the facility in order to determine what potential thermal dangers or threats exist to personnel and equipment. A hazards analysis or risk assessment will provide for the identification of potential hazards and of the necessary corrective actions/measures to prevent or control the hazard. Early in the design of a facility, the processes and equipment may be conceptual and at this stage, a preliminary hazards analysis can be performed. It is early in the design that a preliminary hazards analysis can be most helpful because its... 

Assessment. An analysis of the hazards present in this laboratory show the most significant hazard to be the release of vapor CSM from engineering controls and into the workplace. The significance of this hazard mandates further efforts in system safety in the form of a Preliminary Hazard List (PHL) and a Preliminary Hazard Analysis (PHA). The user must in this instance take an active role in the design review process. 

Preliminary Hazard Analysis. The next step in the process is the development of a PHA. This analysis is the core of the FSS program and as such is vital in eliminating or reducing the inherent hazards associated with this laboratory operation. The PHA is used to further analyze the data identified in the PHL. This enhances the hazard control data base and provides specific recommended corrective action for the resolution of hazardous conditions. A combination of the informational sources used in the PHL development and any additional design information should be used in PHA development. 

Preliminary Hazard Analysis Description. The incorporation of this information into a PHA entry is shown as Table II. This entry describes the proposed actions needed to eliminate or control the hazard (column 6), the risk assessment code assigned after controls (column 7), and the identification of applicable codes and standards (column 8). 

Other possible preliminary safety analysis methods are concept safety review (CSR), critical examination of system safety (CE), concept hazard analysis (CHA), preliminary consequence analysis (PCA) and preliminary hazard analysis (PHA) (Wells et al., 1993). These methods are meant to be carried out from the time of the concept safety review until such time as reasonably firm process flow diagrams or early P I diagrams are available. 

Several qualitative approaches can be used to identify hazardous reaction scenarios, including process hazard analysis, checklists, chemical interaction matrices, and an experience-based review. CCPS (1995a p. 176) describes nine hazard evaluation procedures that can be used to identify hazardous reaction scenarios-checklists, Dow fire and explosion indices, preliminary hazard analysis, what-if analysis, failure modes and effects analysis (FMEA), HAZOP study, fault tree analysis, human error analysis, and quantitative risk analysis. 

The EDS II test program includes testing and design studies needed for a preliminary design of a full-scale pilot plant, a preliminary hazard analysis, development of a full-scale cost estimate, and a schedule for construction and operation of a facility employing the AEA technology. 

Preliminary Hazard Analysis (commonly used in the defense and aerospace industry)... 

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