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An Introduction to Tools and Techniques
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This table summarises some of the Safety Assessment Tools and Techniques available to the safety assessor. Each of these tools has its own advantages and disadvantages and the extent to which these can be used during various phases of the product lifecycle, and the degree to which they can be applied to safety assessments, vary. For a list of Advantages and Limitations of each, see Appendix A to Aircraft System Safety: Military and Civil Aeronautical Applications.
It is extremely important to note that as the complexity of the tool increases so does the degree of training required for the user and/or the need for an experienced evaluation team to conduct the evaluation. On the plus side, the data derived from the more complex methodologies may be more supportable. Unfortunately, the primary disadvantage of such tools is that "trained subject matter experts" may have limited experience in the actual operational environment and, therefore, their evaluations may not be entirely applicable to the certification process.
To hide this text and give you more room to view the table of tools and techniques, click the "minus" sign symbol at the top right of the container surrounding this introduction.
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Tools and Techniques
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| | Name | Description |
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| Electromagnetic Compatibility Analysis | The analysis is conducted to minimize/prevent accidental or unauthorized operation of safety critical functions within a system. Adverse electromagnetic environmental effects can occur when there is any electromagnetic field. Electrical disturbances may also be generated within an electrical system from transients accompanying the sudden operations of solenoids, switches, choppers, and other electrical devices, Radar, Radio Transmission, transformers. [Tarrents, 1980] |
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| Energy Analysis | The energy analysis is a means of conducting a system safety evaluation of a system that looks at the "energetics" of the system. The technique can be applied to all systems, which contain, make use of, or which store energy in any form or forms, (e.g. potential, kinetic mechanical energy, electrical energy, ionising or non-ionising radiation, chemical, and thermal.) [Tarrents, 1980] |
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| Energy Trace Analysis | This hazard analysis approach addresses all sources of uncontrolled and controlled energy that have the potential to cause an accident. Examples include utility electrical power and aircraft fuel [FAA System Safety Handbook, Chapter 9] Sources of energy causing accidents can be associated with the product or process (e.g., flammability or electrical shock), the resource if different than the product/process (e.g., smoking near flammable fluids), and the items/conditions surrounding the system or resource of concern (e.g., vehicles or taxing aircraft). A large number of hazardous situations are related to uncontrolled energy associated with the product or the resource being protected (e.g., human error). Some hazards are passive in nature (e.g., sharp edges and corners are a hazard to a maintenance technician working in a confined area). The purpose of energy trace analysis is to ensure that all hazards and their immediate causes are identified. Once the hazards and their causes are identified, they can be used as top events in a fault tree or used to verify the completeness of a fault hazard analysis. Consequently, the energy trace analysis method complements but does not replace other analyses, such as fault trees, sneak circuit analyses, event trees, and FMEAs. |
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| Energy Trace and Barrier Analysis | Is similar to Energy Analysis and Barrier Analysis. The analysis can produce a consistent, detailed understanding of the sources and nature of energy flows that can or did produce accidental harm. The technique can be applied to all systems, which contain, make use of, or which store energy in any form or forms, (e.g. potential, kinetic mechanical energy, electrical energy, ionising or non-ionising radiation, chemical, and thermal.) [Tarrents, 1980] |
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| Energy Trace Checklist | Similar to Energy Trace and Barrier Analysis, Energy Analysis and Barrier Analysis. The analysis aids in the identification of hazards associated with energetics within a system, by use of a specifically designed checklist. The analysis could be used when conducting evaluation and surveys for hazard identification associated with all forms of energy. The use of a checklist can provide a systematic way of collecting information on many similar exposures. [Tarrents, 1980] |
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| Environment Analysis | Human error reliability assessment technique.
The Environment Analysis can be performed concurrently along with the user and task analysis. Activities or basic tasks that are identified in the task analysis should be described with respect to the specific environment in which the activities are performed (Whiteside, Bennett, & Holtzblatt, 1988; Wixon et al., 1990). |
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| Environmental Risk Analysis | The analysis is conducted to assess the risk of environmental noncompliance that may result in hazards and associated risks. The analysis is conducted for any system that uses or produces toxic hazardous materials that could cause harm to people and the environment. [Tarrents, 1980] |
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| Event and Casual Factor Charting | Utilizes a block diagram to depict cause and effect. The technique is effective for solving complicated problems because it provides a means to organize the data, provides a summary of what is known and unknown about the event, and results in a detailed sequence of facts and activities. [Tarrents, 1980] |
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| Event Tree Analysis (ETA) | ETA is an inductive technique which considers the consequence of an initiating event and the expected frequency of each occurrence.
It is a graphical technique which starts from an initial occurrence (e.g. lightning strike or system condition, such as a rupture of a fuel pipe or loss of power supply) and builds upon this by sequencing the possible events.
It is illustrated as a tree of possible TRUE/FALSE outcomes against each mitigating Mechanism.
Event Tree Analysis starts with a hazard, but instead of working backwards as in the Fault Tree, it works forward to describe all the possible subsequent events and so identify the event sequences that could lead to a variety of possible consequences.
Originally devised to access the protective systems and safety of nuclear reactors, it operates with inductive (i.e. forward) logic by asking the question: "What happens if...".
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| Explosives Safety Analysis | This method enables the safety professional to identify and evaluate explosive hazards associated with facilities or operations.
Explosives Safety Analysis can be used to identify hazards and risks related to any explosive potential, i.e. fuel storage, compressed gases, transformers, batteries.
[Tarrents, 1980] |
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