Hazard identification output

The safety core-process itself starts with the Preliminary Hazard Identification (PHI) and the Preliminary Hazard Assessment (PHA). During diat phase a preliminary hazard list with severities is created via brainstorming and the use of historical data and checklists. Outputs are the preliminary hazard list, including severities and hazard target rates, and initial development process integrity level allocations as detailed in various standards, e.g. Safety Integrity Level (SIL) in lEC 61508 or CENELEC EN 50128. 

Bow-tie diagrams can be used as a stand-alone qualitative hazard identification tool or as the first step in a quantified risk assessment. Depending on the software used, the data on a bow-tie diagram may be output as a hazard register and responsibilities for ensuring that barriers are effective may be assigned. 

Output 2 examines the situation where the hazard had not been identified in the risk assessment, and the system of work had not changed since tlie assessment. The implications are that the hazard identification process in the original risk assessment failed in some way. There are two potential shortfalls here as shown... 

The main output of HAZID is the documentation in the form of the hazard register where all hazards are listed with identification for each section, and cause and consequence and suitable linking with control measures are recorded. This is done in a logical structure and detailed in Clause 3.2.5 of this chapter, and hence is not repeated. Here, one very important point is that all assumptions, debated issues, and uncertainties must be logically recorded for further review. Another issue connected with HAZID study output is its application. The major application area of HAZID by the operator shall include but not be limited to the following ... 

As already outlined, the process models inform the Change Safety Analysis (CSA). The output of the CSA feeds the hazard log and the identification of the safety requirements, as illustrated by Table 7-12 below. 

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