Introduction to Systems Safety Engineering
ISE 741 North Carolina State University
ISE 741, Fall 2012
• Faculty Introduction
– Dr. Nancy Currie – Dr. David Kaber – Dr. Guk-Ho Gil
http://www.jsc.nasa.gov/Bios/htmlbios/currie.html http://people.engr.ncsu.edu/dbkaber/ http://www.ise.ncsu.edu/people/staff/gil.php http://courses.ncsu.edu/ise741/lec/001/
• Course Website
– Course Syllabus
– Communication Information
– Course Schedule
• Course Topics
• Systems Safety Process • Hazard Reduction & Safety Standards • Safety Management • Preliminary Hazard List (PHL) • Preliminary Hazard Analysis (PHA) • Subsystem Hazard Analysis (SSHA) • System Hazard Analysis (SHA) • Process Safety Analysis • Probability & Reliability review • Failure Modes & Effects Analysis (FMEA) • • • • • • • • Boolean Logic Review Fault Tree Analysis (FTA) Cut Sets & Path Sets Software Safety Analysis Energy Trace Barrier Analysis Sneak Circuit Analysis Probabilistic Risk Assessment (PRA) Accident Investigation and Reporting
Perspectives on Systems Safety Engineering
• “As our technology expands, as our wars multiply, and as we invade more and more of nature, we create systems – organizations, and the organization of organizations – that increase our risk for the operators, passengers, innocent bystanders, and for future generations.” – Charles Perrow, Normal Accidents “Although many designers can appreciate the difficulty of creating designs without hazards or with effective guards, few designers have a basis (or the expertise) to understand the complexities of designing a warning.” – Ward Allen, “What do design engineers really know about safety?”
“If a sufficient number of management layers are superimposed on top of each other, it can be assured that disaster is not left to chance.” – Norm Augustine, Augustine Laws “Complex systems almost always fail in complex ways.” - Columbia Accident Investigation Board and National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling
A composite, at any level of complexity, of personnel, procedures, materials, tools, equipment, facilities, and software. The elements of this composite entity are used together in the intended operational or support environment to perform a given task or achieve a specific production, support, or mission requirement.
The application of engineering and management principles, criteria and techniques to achieve acceptable mishap risk, within the constraints of operational effectiveness and suitability, time and cost, throughout all phases of the system life cycle
“Systems Safety Engineering”
The application of scientific and engineering principles, criteria, and techniques to identify and eliminate hazards, in order to reduce the associated risk through: Identification of systems hazards and associated causes Development of engineering, operational, or management controls to either eliminate hazards or mitigate their consequences Evaluation of the strength of control measures Continual monitoring of the system to determine any changes in hazards or associated controls
The process of characterizing hazards within risk areas and critical technical processes, analyzing them for their potential mishap severity and probabilities of occurrence, and prioritizing them for risk mitigation actions
* Hazard is a generic reference to potential causal factors of accident scenarios, whether direct or indirect, primary or contributory.
Historical Perspective of Systems Safety Engineering
• Code of Hammurabi - ~1750 BC • First laws covering compensation for injuries codified – Middle Ages • Lloyd’s Register of British...
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