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Risk Assessment Using the Three Dimensions of Probability (Likelihood), Severity, and Level of ControlTraditional hazard analysis techniques utilize a two-dimensional representation of the results determined by relative likelihood and severity of the residual risk. These matrices present a quick-look at the Likelihood (Y-axis) and Severity (X-axis) of the probable outcome of a hazardous event. A three-dimensional method, described herein, utilizes the traditional X and Y axes, while adding a new, third dimension, shown as the Z-axis, and referred to as the Level of Control. The elements of the Z-axis are modifications of the Hazard Elimination and Control steps (also known as the Hazard Reduction Precedence Sequence). These steps are: 1. Eliminate risk through design. 2. Substitute less risky materials for more hazardous materials. 3. Install safety devices. 4. Install caution and warning devices. 5. Develop administrative controls (to include special procedures and training.) 6. Provide protective clothing and equipment. When added to the twodimensional models, the level of control adds a visual representation of the risk associated with the hazardous condition, creating a tall-pole for the least-well-controlled failure while establishing the relative likelihood and severity of all causes and effects for an identified hazard. Computer modeling of the analytical results, using spreadsheets and threedimensional charting gives a visual confirmation of the relationship between causes and their controls
Document ID
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Watson, Clifford
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 24, 2013
Publication Date
May 19, 2010
Subject Category
Statistics And Probability
Report/Patent Number
Meeting Information
Meeting: Fourth International Association for the Advancement of Space Safety
Location: Huntsville, AL
Country: United States
Start Date: May 19, 2010
End Date: May 21, 2010
Distribution Limits
Work of the US Gov. Public Use Permitted.
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