Hazard identification technique

Hazard identification builds the foundation on which subsequent quantitative frequency and/or consequence estimates are made. Many companies have been using the hazard identification techniques listed in Figure 7 for... 

A hazard identification technique in which all known failure modes of components or features of a system are considered in turn, and undesired outcomes are noted... 

An opportimity for error recovery would have been to implement a checking stage by a supervisor or independent worker, since this was a critical maintenance operation. However, this had not been done. Another aspect of the unforgiving environment was the vulnerability of the system to a single human error. The fact that the critical water jacket flow was dependent upon a single pump was a poor design that would have been detected if a hazard identification technique such as a hazard and operability study (HAZOP) had been used to assess the design. 

All of these factors determine the stress experienced by the workers and the extent to which operational errors will be recovered before disastrous consequences have ensued. In this context, hazard identification techniques, such as hazard and operability studies (HAZOP), failure modes and effects and criticality analysis (FMECA), fault trees, and others are useful in making the process environment more forgiving. 

The commonly used management systems directed toward eliminating the existence of hazards include safety reviews, safety audits, hazard identification techniques, checklists, and proper application of technical knowledge. 

Identifying and analyzing fire hazards and scenarios is the next step in a fire risk assessment. The hazard identification should be structured, systematic, audit-able, and address all fire hazards, including nonprocess fires. The result of the hazard identification is a list of potential fire hazards that may occur at the facility, for example, jet, pool, flash, BLEVE, electrical, or Class A fires. This list should also include the location where each fire could occur. Hazard identification techniques used to identify potential hazards are shown in Table 6-1. 

In this section, a selection of commonly used hazard identification techniques is presented. These techniques can be used in the fine chemicals and pharmaceutical industries. The methods presented here are designed to provide a systematic search for hazards with the final objective of providing a comprehensive analysis. 

There exists a whole battery of methods for the identification of hazards in the literature.4 The hazard identification techniques suitable for various stages of a project are shown in Table 3.1. Among the techniques noted in Table 3.1 the most important method is safety audits, which cover the management system and specific technical features at site level and the management system at plant level. 

Table 3.1 Hazard identification techniques appropriate to different project stages...

NUS Corp., HAZOP Study Team Training Manual. Predictive Hazard Identification Techniques for Dow Corning Facilities, Gaithersburg, MD (July 1989). 

A list of the more commonly used hazard identification techniques is provided below. They are discussed in greater detail in later sections of this chapter and also in Chapter 5. 

For process plants involving physical or chemical processes, a formal hazard identification technique such as what-if or a safety checklist is deployed to identify the hazard scenarios... 

Identification of functions (and the compilation of the functional tree) is further complicated by the fact that the preliminary FHA considers only functional hazards and, when issued, often receives criticism for hazards not yet identified (but which will be once hazard identification techniques such as the ZSA, CCA and PRA are employed) to the maturing design. 

In most civil aviation System Safety Assessments, this event originates from a Function Hazard Analysis (FHA, see Chapter 3), but it can also come from any other hazard identification technique (e.g. ZS A or PRA). An FTA is a deductive approach (i.e. top down) that determines how a given state (i.e. the undesired event) can occur. It does not identify all failures in a system in a way that inductive tproaches (such as an FMEA) would. 

Within the limitations described above, particularly the potential to miss new hazards, checklists can be a powerful, cost-effective hazard identification technique. 

Chemical reaction and process hazard identification is an important step before the startup of a manufacturing process. Several of the incidents listed below could have been avoided if hazard identification techniques had been followed by the manufacturer prior to startup. 

In addition to the previously mentioned reaction hazard identification techniques, the following reaction process design considerations need to be considered for avoiding hazards ... 

The method starts with a list of all the process hazards on the installation as identified by HAZOP or other hazard identification technique. The hazards are analysed in terms of ... 

For facilities that are still in the design stage, the actions taken, particularly during the Risk Assessment step, will change for each iteration. For example, early evaluations of risk will use a HAZID (Hazard Identification) technique later on, as detailed engineering information becomes available, the more comprehensive HAZOP (Hazard and Operability Study) method will be used. 

The most suited hazard identification techniques are applied so that in-depth analysis is possible. 

Since hazard identification is the foundation of future courses of action, the selection of a proper identification technique is essential. The following are the features expected of hazard identification techniques ... 

The task analysis technique has been developed mainly to handle human factors (in HAZID and other methods). In HAZID this is helpful in addressing human factors such as human error, man—machine interface, and procedural error. Of the various hazard identification techniques, task analysis is one of the most important. The other techniques are discussed in subsequent chapters, but here discussions will be on task analysis. Task analysis is the study of what users need to do, in terms of actions and/or cognitive processes, to achieve a task objective. There are several factors, such as task duration, repetitive frequency, task allocation, complexity, equipment, ambience, and environmental conditions, which are required for the task and they very much influence the performance. At times, tasks are often used interchangeably with process. 

Step I There are various hazard identification techniques, discussed earlier in the chapter, that can be applied to identify the initiating event. Suppose there is a gas leakage resulting in a fire. In this case, gas leakage is the main initiating event. 

Identification of initiating event Various hazard identification techniques... 

The two main hazardous identification techniques are the comparative and the fundamental methods. 

This is based on considerations of deviation from original design. A hazard study is carried out to identify which events, or actions, may trigger off hazardous situations. Fundamental hazard identification techniques include such techniques as ... 

Failure Mode and Effects Analysis (FEMA)—FEMA is a tabulation of facility equipment items, their potential failure modes, and the effects of these failures on the equipment or facility. Failure mode is simply a description of what caused the equipment to fail. The effect is the incident, consequence, or system response to the failure. It is usually depicted in tabular format and expresses failures in an annual estimation. A FEMA is not useful for identifying combinations of failures that can lead to incidents. It may be used in conjunction with other hazard identification techniques such as HAZOP for special investigations such as critical or complex instrumentation systems. There is also a Failure Modes, Effects, and Criticality Analysis (FMECA), which is a variation of FMEA that includes a quantitative estimate of the significance of the consequence of a failure mode. 

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