System safety and reliability analyses identify and document hazards, hazard controls, and critical components to ensure known hazards are subjected to management review and approval prior to design fabrication and testing. Safety and reliability analyses start at design conception and continue throughout the system lifecycle.

System Assurance Analysis (SAA) is an in-depth safety analysis that consolidates the safety and reliability analyses performed on a system into one report. The SAA typically includes:

  • Criticality Assessment (CA) – Categorizes all system functions as either critical or non-critical. Functions identified as critical require further analysis and evaluation.
  • Failure Modes and Effects Analysis (FMEA) – Analysis of a system to define the worst-case failure effects for each component providing a critical system function. The FMEA is a combined effort across the entire design team and implemented throughout each design process to ensure the system adheres to failure tolerance requirements.
  • Hazard Analysis (HA) – Identifies and addresses hardware, software, and environmental hazards that arise across the lifecycle of the system from the initial design and development phase through implementation and disposal activities. Hazards that take place across systems are considered integrated hazards.
  • Fault Tree Analysis (FTA) – Illustrates the combination of failures that cause an undesired Top Event using software such as Windchill Quality Solutions (formerly Relex FTA). FTAs can be either qualitative or quantitative with SAAs typically containing qualitative FTAs to evaluate events and determine root causes. Mitigations are evaluated to reduce the probability of an adverse event occurring.

Nelson Engineering works with clients and tailors the constituent SAA analysis approaches depending on the type of system being analyzed, its hazardous attributes, and the extent the system design can reasonably eliminate or mitigate hazards and risks.