Introduction to System Safety Engineering Objective Understand the

Introduction to System Safety Engineering

Objective �Understand the role of System Safety Engineering within SE and the life cycle of a product. �Understand key principles, definitions, and concepts. 11/9/2020 2

Systems Safety Engineering �Assumes an understanding of Systems Engineering �Not intended to teach the details of Systems Safety �Enables Systems Engineers, Managers, and others to understand what to expect, what is required, and in what time frame from a Systems Safety Program. �Identifies System Safety activities supporting each phase of a systems life- cycle. 11/9/2020 3

Definitions �Safety ◦ Freedom from conditions that can cause death, injury, occupational illness, damage to or loss of equipment or property, or damage to the environment. 11/9/2020 4

Definitions �System Safety ◦ The application of engineering and management principles, criteria, and techniques to achieve acceptable risk within the constraints of operational effectiveness and suitability, time, and cost throughout all phases of the system life-cycle 11/9/2020 5

Definitions �Systems Safety Engineering ◦ The application of engineering and management principles, criteria, and techniques to optimize all aspects of safety within the constraints of operational effectiveness, time, and cost throughout all phases of the system life cycle 11/9/2020 6

Definitions �System Safety Management ◦ All plans and actions taken to identify hazards, assess and mitigate associated risks, and track, control, accept, and document risks encountered in the design, development, test, acquisition, use, and disposal of systems, subsystems, equipment, and infrastructure. 11/9/2020 7

Definitions �Mishap ◦ An event or series of events resulting in unintentional death, injury, occupational illness, damage to or loss of equipment or property, or damage to the environment. ◦ Mishap includes negative environmental impacts from planned events. 11/9/2020 8

Definitions �Hazard ◦ A real or potential condition that could lead to an unplanned event of series of events (mishap) resulting in death, injury, occupational illness, damage to or loss of equipment or property, or damage to the environment. 11/9/2020 9

Definitions �Severity ◦ The magnitude of potential consequences of a mishap to include death, injury, occupational illness, damage to or loss of equipment or property, damage to the environment, or monetary loss. 11/9/2020 10

Definitions �Probability ◦ An expression of the likelihood of occurrence of a mishap �Risk ◦ A combination of the severity of the mishap and the probability that the mishap will occur. �Risk level ◦ The characterization of risk as either High, Serious, Medium, or Low. 11/9/2020 11

Definitions � Mitigation measure ◦ Action required to eliminate the hazard or when a hazard cannot be eliminated, reduce the associated risk by lessening the severity of the resulting mishap or lowering the likelihood that a mishap will occur. � Acceptable Risk ◦ Risk the appropriate acceptance authority is willing to accept without additional mitigation � Causal Factor ◦ One or several mechanisms that trigger the hazard that may result in a mishap 11/9/2020 12

Definitions �Initial Risk ◦ The first assessment of the potential risk of an identified hazard. Initial risk establishes a fixed baseline for the hazard. �Life-cycle ◦ All phases of the system’s life, including design, research, development, test and evaluation, production, deployment (inventory), operations and support, and disposal. 11/9/2020 13

Definitions �Event Risk ◦ The risk associated with a hazard as it applies to a specified hardware/software configuration during an event. Typical events include Developmental Testing/Operational Testing (DT/OT), demonstrations, fielding, post-fielding tests. 11/9/2020 14

Definitions �System-of-Systems (So. S) ◦ A set or arrangement of interdependent systems that are related on connected to provide a given capability. �Target risk ◦ The projected risk level to achieve by implementing mitigation measures consistent with the design order of precedence. 11/9/2020 15

Definitions �Safety-related ◦ A condition, event, operation, process, or item whose mishap severity consequence is either Marginal or Negligible �Safety-significant ◦ A condition, event, operation, process item that is identified as either safetycritical or safety related 11/9/2020 16

Definitions �Safety-critical ◦ A term applied to a condition, event, operation, process, or item whose mishap severity consequence is either Catastrophic or Critical. �Safety-critical function (SCF) ◦ A function whose failure to operate or incorrect operation will directly result in a mishap or either Catastrophic or Critical severity. 11/9/2020 17

Definitions �Safety-Critical item (SCI) ◦ A hardware or software item that has been determined through analysis to potentially contribute to a hazard with Catastrophic or Critical mishap potential, or that may be implemented to mitigate a hazard with Catastrophic or Critical mishap potential. 11/9/2020 18

Definitions �Re-use items ◦ Items previously developed under another program or for a separate application that are used in a program. 11/9/2020 19

Objectives �Prevent accidents/mishaps �Designed into the system in cost effective manner a timely, ◦ Very costly to redesign later �Hazards are identified, evaluated, and eliminated or the associated risk is reduced to a level acceptable throughout the entire life cycle of a system �Use historical safety data, including lessons learned 11/9/2020 20

Objectives (continued) �Minimum risk is undertaken when using new designs, materials, and production and test techniques �Actions taken to eliminate hazards or reduce risk to an acceptable level are documented. �Retrofit actions are minimized �Minimize hazardous materials. If required, evaluate for safety and ease of disposal 11/9/2020 21

Objectives (continued) �Save your lessons learned for the next project �Hazards identified after production are minimized 11/9/2020 22

Benefits of Systems Safety �Help cause and ensure the safe design of products ◦ Objective approach where both use and possible misuse is considered ◦ Ensure compliance with Laws, requirements, and other contractual items pertaining to safe product design 11/9/2020 23

Benefits of Systems Safety (continued) �To ◦ ◦ ◦ expensive not to have a program Product Recall Product Liability (Lawsuits) Costly Retrofits Accidents resulting in injury and death Punitive damages Negative Publicity 11/9/2020 24

Actions for Systems Safety �Document the Systems Safety Approach �Identify and document hazards �Assess and document risk �Identify and document risk mitigation measures �Reduce risk �Verify, validate and document risk reductions �Accept risk and document �Manage life-cycle risk 11/9/2020 25

Key Principles �A basic requirement of the total system � Must be planned ◦ Integrated and comprehensive ◦ Interrelated, sequential, and continuing ◦ Affects facilities, equipment, procedures, and personnel ◦ Applies to all phases (conceptual, design, production, deployment ◦ Includes transportation and logistics support ◦ Disposal ◦ Includes off the shelf acquisitions 11/9/2020 FAA Ch 3 26

Key Principles (continued) � Inherent safety comes from the basic system design ◦ Improvements to inherent safety are best achieved early � Management resolves conflicts between safety and other design requirements � Design Safety hierarchy ◦ Design to the minimum hazard ◦ Create Safety devices ◦ Include warning devices ◦ Create Special Procedures 11/9/2020 27

System Safety over the System Life Cycle REQMNTS ANALYSIS HAZARD ID AND TRACKING RISK RESOLUTION PHA SAFETY SPEC INPUTS SSHA COMPLIANCE ASSESSMENT SHA REVIEW ECN/ECP DEV/WAIVR O&SHA FCA SRR CONCEPT EXPLORATION & DEM/VAL CDR PDR REQUIREMENTS ANALYSIS & VERIFICATION SAFETY REQRMNTS VERIFICATION PCA SSERs FIELD MONITORING DETAILED HAZARD ANALYSES PROGRAM PHASE & MILESTONES PRODUCTION, OPERATION AND SUPPORT E&MD 11/9/2020 28

� EARLY DESIGN INFLUENCE OFFERS GREATEST OPPORTUNITY TO PROTECT PEOPLE AND OUR ENVIRONMENT High Opportunity to Change Difficulty of Change Low Idea Design Prototype Pilot Production 11/9/2020 Usage Disposal/ Recycle 29

Key Principles (continued) � System Safety requirements must be consistent with other program requirements and must be well defined. � Systems analysis are basic tools for systematically developing design specifications ◦ Analysis are performed to �Identify hazards and corrective actions �Review safety considerations in tradeoffs �Determine/evaluate safety design requirements �Determine/evaluate operational, test , logistics requirements �Validate qualitative/quantitative requirements have been met 11/9/2020 30

Key Principles (continued) �Nature and severity of hazards used to change design requirements ◦ ◦ Called risk assessment Hazard categories Hazard probability Risk Management 11/9/2020 31

Key Principles (continued) �System Safety Management ◦ Defines function, authority, and interrelationships ◦ Exercises appropriate controls ◦ Assures optimum safety ◦ Precludes degradation of inherent safety 11/9/2020 32

Key Principles (continued) �Degree of safety directly dependent upon management emphasis by customer and contractors. �Results of safety effort depend on procurement agency clearly stating objectives/requirements 11/9/2020 33

Key Principles (continued) �Managing activity responsibilities ◦ Plan, organize and implement system safety program ◦ Establish safety requirements for system design ◦ State safety specification in contract ◦ Requirements for activities in contract ◦ Contractually applicable safety data ◦ Ensure complete System Safety Program Plan (SSPP) 11/9/2020 34

Key Principles (continued) �Managing activity responsibilities (continued) ◦ Review implementation of SSPP ◦ Supply historical data ◦ Review contractor system safety effort/data ◦ Ensure specifications are updated with test analyses results ◦ Establish system safety groups 11/9/2020 35

Key Principles (continued) � Software hazard analysis ◦ Begin early in development and may be updated ◦ Is a flow down requirements process followed by an upward-flow verification process � Elements of an effective systems safety program ◦ Planned approach to accomplish tasks ◦ Qualified people ◦ Authority to implement tasks through all levels of management ◦ Appropriate manning/funding 11/9/2020 36

Introduction to Systems Safety Engineering �Benefit from understanding the concepts of systems safety engineering and allow you to better manage your projects ◦ ◦ Risk Acceptance Risk Reduction Expected loss may be estimated Maximum Safety consistent with operational requirements 11/9/2020 AFSS 4 37

Introduction to Systems Safety Engineering ◦ Safety must be designed in. ◦ Requires both engineering and management. ◦ Must be consistent with other program or design requirements. ◦ Human error can void all standards incorporated by the design. 11/9/2020 AFSS 4 38

Wrap-up �System Safety is a key to designing a cost effective and safe system. �Be proactive. Get your safety engineer involved early in the design process. 11/9/2020 39