System safety efforts

This complacency factor is so common that any system safety effort must include ways to deal with it. SUBSAFE, the US. nuclear submarine safety program, has been particularly successful at accomplishing this goal. The SUBSAFE program is described in chapter 14. 

The upper left loop represents the Space Shuttle safety program, which when operating effectively is meant to balance the risks associated with loop Rl.The external influences of budget cuts and increasing performance pressures, however, reduced the priority of safety procedures and led to a decrease in system safety efforts. 

Adding to the problems is the fact that system safety efforts led to launch delays when problems were found, which created another reason for reducing the priority of the safety efforts in the face of increasing launch pressures. 

The combination of the decrease in safety efforts along with loop B2 in which fixing the problems that were being found increased complacency, which also contributed to reduction of system safety efforts, eventually led to a situation of unrecognized high risk. 

The roots of the system safety effort extend back at least to the 1940s and 1950s. Accurately tracing the early transition from the traditional trial-and-error approach to safety to the first-time safe effort that lies at the heart of system safety is really impossible, but such a transition occurred as both aircraft and weapon systems became more complex and the consequences of accidents became less acceptable. 

Most agree that one of the first major formal system safety efforts involved the Minuteman intercontinental ballistic missile (ICBM) program. A series of pre-Minuteman design-related silo accidents probably provided at least part of the incentive (U.S. Air Force 1987). 

Early system safety requirements were generated by the US. Air Force Ballistic System Division. Early air force documents provided the basis for MIL-STD-882 (July 1969), System Safety Program for Systems and Associated Subsystems and Equipment Requirements for. This document (and revisions MIL-STD-882A and MIL-STD-882B) became, and remain, the bible for the Department of Defense (DOD) system safety effort (Moriarty and Roland 1983). 

In addition to weapon systems, other early significant system safety efforts were associated with the aerospace industry, including civil and military aviation and the space program. 

In the late 1960s, the Atomic Energy Commission (AEC), aware of system safety efforts in the DOD and NASA communities, made the decision to hire William G. Johnson, retired manager of the National Safety Council, to develop a system safety program for the AEC. 

Developing a new approach to system safety that incorporated the best features of existing system safety efforts... 

The work by Bill Johnson was expanded and supplemented throughout the 1970s by the System Safety Development Center (SSDC) in Idaho Falls, Idaho. The MORT program provides the direction for this second major branch of the system safety effort. 

Significant programs initiated or developed in the 1980s include the facility system safety efforts of the Naval Facilities Command and the US. Army Corps of Engineers and initiatives in the petrochemical industry. 

In 1985, the American Institute of Chemical Engineers (AIChE) initiated a project to produce the Guidelines for Hazard Evaluation Procedures. This document, prepared by Battelle, includes many system safety analysis tools. Even though frequently identified as hazard and operability (HazOp) programs, the methods being developed by the petrochemical industry to use preliminary hazard analyses, fault trees, failure modes, effects, and criticality analyses, as well as similar techniques to identify, analyze, and control risks systematically, look very much like system safety efforts tailored for the petrochemical industry (Goldwaite 1985). 

Name three areas in which system safety efforts were initiated or developed during the 1980s. 

One of the major problems confronting the system safety community is a lack of standardization or commonality. (This problem is discussed in detail in Chapter 4.) Presenting universally accepted definitions to even basic terms is therefore difficult because, by and large, they do not exist. The following terms are defined in nontechnical language to ensure the reader understands each term as used in this book. Specific definitions from documents widely used in the system safety effort are contained in the glossary, and definitions used by specific organizations are included in Chapter 3. 

The safety precedence sequence originated as part of the system safety effort and is one of the few tools that is common to nearly all system safety efforts. 

The system safety effort is sometimes called an approach, a discipline, a concept, a doctrine, and/or a philosophy. 

The system safety effort strives to be proactive by very early identification, analysis, and control of hazards to produce first-time safe systems. 

The government plan for developing, communicating, and monitoring the system safety effort may be called the system safety management plan. 

The primary objectives of the system safety effort are to identify, analyze, and control hazards to the extent possible with constraints of operational effectiveness, time, and money. 

In most organizations that have a reliability effort separate from the safety or system safety effort, an FMEA is considered a reliability tool. The safety version is called a failure modes and effects criticality analysis (FMECA). 

The system safety effort should begin when the project begins and continue throughout the life cycle. The system safety effort concentrates, however, on... 

Management has the overall responsibility for ensuring that system safety programs are established, that they are adequately staffed at all levels, that the training is conducted for all personnel associated with the system safety effort, that safety concerns are identified and communicated, and that adequate resources are allocated. 

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). 

A system safety working group should have representatives from at least four groups or communities. Name them and discuss the skills or knowledge that each representative brings to the system safety effort. 

An important part of the government system safety effort is to assure that system safety requirements are specified clearly and correctly in contract documents. The formats for system safety products or deliverables are generally prescribed by data item descriptions (DIDs). Other specific requirements concerning the exact documents to be produced and delivered are specified in the contractor requirements data list (CRDL). 

Most major DOD agencies and contractors involved in the traditional weapons and aerospace programs have internal system safety organizations to plan and implement system safety efforts. The majority of the nation s system safety engineers tend to work for these organizations and, by and large, provide the membership for the System Safety Society. 

The total system safety effort for complex aerospace programs may involve several levels of organization. A typical six-level system safety effort may be organized as follows ... 

Level One. Corporate or headquarters. The system safety effort at this level usually consists of general oversight of multiple programs and development of policies and standards. 

Level Four. Contractor s engineering system safety program. This level is the working level for the system safety engineer and the program system safety effort. 

There are many similarities between NASA s system safety efforts and those of the Department of Defense, especially the USAF Space Division. The... 

The NASA system safety manual. NHB 1700.1(V-3), is one of the several system safety documents supporting NASA system safety efforts. 

Some of the other key documents in the NASA system safety effort include... 

Low-risk facilities are those with low energy levels and those with which the COE has a considerable amount of trouble-free experience, such as basic administrative buildings and housing. The system safety effort for these facilities may consist primarily of the PHL, with no additional analysis required. 

The HazOp study differs from the FMEA and ETBA in that some suggest that the best time to conduct a HazOp is when the design is fairly firm (Goldwaite 1987). Conventional system safety wisdom dictates that the system safety effort be as far upstream as practical, with a facility preliminary hazard analysis developed as part of the initial design effort and completed by the 35% stage. Also, a HazOp study tends to include human factors and operator errors whereas a traditional FMEA or ETBA normally examines hardware failures only. 

In summary, the broad HazOp effort of the chemical industry is a facility system safety effort. It is one of the first such efforts to originate in the private sector. A sharing of information between the HazOp advocates and those promoting facility system safety should be mutually beneficial. 

Even though MIL-STD-882B and MORT tout the importance of a system safety effort throughout the life cycle, both approaches fall somewhat short of full implementation. The MIL-STD-882B efforts cover all phases of the acquisition cycle, but most have no real application after a system has been deployed. In contrast, MORT probably provides the greatest benefits during the operations phase. 

Discuss the risk categories used in the facility system safety effort. 

What is MORTl What government agency uses MORT as the basis for their system safety effort ... 

Eight general problem areas need to be addressed before the system safety effort can provide the safety services that will be needed in the next century. Many of these problems are interrelated. 

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