System safety tasks

Air Force top management support of system safety has not gone unnoticed by contractors. They now seem more than willing to include system safety tasks, not as window dressing but as a meaningful activity [70, pp. 5-11]. 

The government agency (or other procuring organization) for whom a system (or product) is being developed must determine the objectives and specifications for the project. The specifications should include standards of safety performance and define the levels of acceptable risk. The specific system safety tasks and requirements must also be defined. 

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). 

Fignre 2-5 Relative relationship of system safety tasks (analyses and review) to life cycle phases for a simple one-of-a-kind system. 

At the working level, system safety tasks are normally performed by a system safety working group (SSWG). One of the reasons that a system safety working group or a team approach is generally used in system safety efforts is that multiple talents and disciplines are required in order to provide for the first-time safe, efficient operation of the entire system (Fig. 2-6). 

List the three basic system safety tasks. 

Level Two. Procurement activity. At the contracting level, the system safety task is to convert requirements and tasks into contractual specifications. 

It is difficult to explain the whys and hows of the System Safety discipline when there is a lack of agreement within the discipline as to just what the task really is. At a meeting of approximately 50 System Safety engineers, each engineer was asked to provide a definition of system safety. Of those 50 fully-qualified and experienced System Safety engineers, at least 30 had distinctly different ideas of what constitutes the system safety task. Very little standardization currently exists between agencies or even between the directives, regulations, and standards that implement the requirement. (USAF 1987)... 

What are the three broad categories of system safety tasks Who is generally responsible for each category ... 

The purpose of the system safety program plan (SSPP) is to identify the specific system safety requirements for a given project, to include specified system safety tasks, risk assessment methodology and risk acceptance criteria, system safety products and milestones, and system safety organization. 

Figure 9-5 An example of a continuation milestone chart depicting system safety tasks and relative timing for a simple system safety program. SSWG+ indicates that persons other than, or in addition to, the SSWG may be involved.

Like the RAC, the quality of the TREC is dependent on the quality of the input data. A very important system safety task is validating and updating the... 

Managnag activity The organizational element of DoD assigned acquisition management responsibility for the system, or prime or associate contractors or subcontractors who wish to impose system safety tasks on their suppliers (MIL-STD-882B). 

System safety management An element of management that defines the system safety program requirements and ensures the planning, implementation and accomplishment of system safety tasks and activities consistent with the overall program requirements (MIL-STD-882). 

As Stated previously, system safety developed or evolved as a direct result of a need to ensure, to the greatest extent possible, reliability in the safe operation of a system or set of systems (especially when a given system is known to be hazardous in nature). While no system can be considered completely or 100% reliable, system safety is an attempt to get as close as practical to this goal. Over the years, numerous techniques and methods used to formally accomplish the system safety task have also evolved and have further expanded our capabilities to examine systems, identify hazards, eliminate or control them, and reduce risk to an acceptable level in the operation of that system. These analytical methods and/or techniques are known by many names such as— but certainly not limited to—the following common system safety tools ... 

The job safety analysis (JSA) [also referred to as the job hazard analysis (JHA)], which is a more simplified form of task analysis, has been a longstanding tool for task and function analysis. JSA has been available and utilized in general industry for many years by the industrial safety community. However, many practitioners do not understand or are simply unfamiliar with the connection between the JSA and the system safety tasks of hazard identification and analysis. It has even been suggested by some in the profession that the JSA itself is a type of oversimplified system safety analysis and, if performed earlier in the job development phase, could be used as the basis of a preliminary hazard analysis for a specific task or set of tasks. However, because JSA is often (if improperly) used to analyze a function only after it has been implemented, much of the data is not factored into the system safety process. The primary purpose of the JSA is to uncover inherent or potential hazards that may be encountered in the work environment. This basic definition is not unlike that previously discussed regarding the various system safety analyses. The primary difference between the two is subtle but important and is found in the end-use purpose of the JSA. Once the job or task is completed, the JSA is usually used as an effective tool for training and orienting the new employee into the work environment. The JSA presents a verbal picture of a specific job. 

System Safety Tasks Those activities, such as hazard analysis, associated with the system safety engineering discipline that are performed to accomplish the system safety program objective. 

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