Preliminary hazard analysis system description

First, collect the input documents and reference resources. The primary input documents include an analytical tree and/or block diagram, drawings, and narrative descriptions of the system. The most important resources are a data base, lessons learned file, historical data, and/or other source(s) of failure rates or other reliability statistics. The preliminary hazard list (PHL), preliminary hazard analysis (PHA) and any other hazard analyses should also be available. 

This example will develop a hardware FMEA for a proposed system that is well into the design phase of the product life cycle. For informational purposes, it is assumed that a preliminary hazard analysis was previously performed during the early stages of the design phase of this system. The information from the PHA will be used to assist in the development of the hardware FMEA. It should also be noted that the nature of a FMEA requires evaluation of subsystems, subassemblies, and/or components. For this reason, more detailed and specific descriptive information is provided here than that supplied for previous examples discussed in this text. 

Software Preliminary Hazard Analysis This type of analysis is used to identify software program routines that are considered to be safety-critical, and thus is conducted prior to software program coding. To perform the analysis, the analyst should make reference to any available system specifications, interface documentation, functional flow diagrams, software flowcharts, storage and file allocation specifications, and any other program descriptive information. 

Hazard and risk analysis To determine the hazards and hazardous events of the EUC and the EUC control system (in all modes of operation), for all reasonably foreseeable circumstances including fault conditions and misuse. To determine the event sequences leading to the hazardous events determined. For the preliminary hazard and risk analysis, the scope will comprise the EUC, the EUC control system and human factors. Further h r analysis may be needed later as the design develops. Information acquired in step 2 Description of and information relating to the hazard and risk analysis. 

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