Hazard identification task analysis technique

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. 

Safety and reliability of chemical process plants are such important issues, they deserve the best techniques to prevent problems occurring. To minimize risks resulted from operating problems and hazardous events, process system safety and reliability analysis is often employed. This is a rigorous approach undertaken to improve system reliability and safety. The approach consists of three main tasks hazard identification, risk estimation, and risk control. 

The first task, hazard identification, is crucial in process system safety analysis, because the effectiveness of the other two tasks depends on it. The traditional methods for identifying hazards during the 1960 s (including process reviews , codes of practice , checklists , and safety audit ) were no longer considered adequate in the 1970 s. There was a need for a technique which could anticipate hazardous problems, particularly in areas of novelty and new technology where past experience was limited. 

A typical system safety task for hazard identification would be the preparation of a preliminary hazard list (PHL). Hazard identification or discovery is accomplished by reviewing lessons learned, accident reports, and other historical data. A PHL may be prepared through an informal conference, the use of checklists, and occasionally other techniques such as energy trace and barrier analysis (ETBA). 

The safety community provides expertise in hazard identification, analysis, and control techniques. TTie safety representative may serve as the primary advisor to the chairperson in articulating system safety goals, tasks, and responsibilities. The safety representative frequently has the job of writing or drafting documents generated by the SSWG. 

Hazard identification Identify hazards and consequences of exposure. Hazards are identified by analyzing the tasks grouped by function. During the identification of each task, the risk analysis assesses the potential consequences of exposure to the hazards. The classic problem solving format Who, What, Where, When, Why, and How (How much How Many ) Is used to define the root cause. This method is called the 5W2H method that is used in Six Sigma techniques to help to identify a root cause. 

Where a definitive identification of the contents of the munition is required, it will normally be necessary to breach the munition case and take and analyse a sample of the chemical fill. This is a difficult and hazardous task, and will normally be attempted only in the field, in exceptional circumstances. Techniques for safely penetrating a munition in the field have, however, been developed. One system, developed by the United Kingdom, is based on the use of a commercial nail gun to penetrate the case of thin walled munitions. A special rubber patch is first placed on the wall of the munition and the nail gun, fitted with a specially designed hardened steel pin, is clamped to the wall of the munition. The gun is set up so that it can be fired remotely, and when this is done the steel pin is driven through the rubber patch and penetrates the wall of the munition. The rubber patch reduces the risk of leakage due to any over-pressure present within the munition. Once the pin has been safely inserted, the munition is transferred to a sealed glovebox. The pin can then be carefully removed and a sample of the fill extracted via the resulting hole in the munition wall for chemical analysis. 

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