glossary-term: Key Concept

  • August 2, 2025
    Mode of operation, in functional safety, specifies how often a safety function is required to act—categorized as low demand, high…
  • May 6, 2025
    Validation confirms that the installed SIS performs according to the SRS, usually through integrated testing like SAT or SIT.
  • May 6, 2025
    SC indicates a device's resistance to design-related faults. A SIL 2 device must meet SC 2. Higher SIL = higher…
  • May 6, 2025
    STR is how often a SIF activates unintentionally, causing a false trip or shutdown. Low STR = high availability.
  • May 6, 2025
    The Safety Requirements Specification (SRS) documents all required functions, response times, SIL levels, and proof test details for your safety…
  • May 5, 2025
    SIL is a rating (1–4) that defines how much risk reduction a SIF must achieve. It ties directly to PFDavg…
  • May 5, 2025
    An SIS is the complete safety system made of one or more SIFs. It’s separate from the BPCS and follows…
  • May 5, 2025
    A SIF is a specific function that responds to hazards—using sensors, logic solvers, and final elements to bring the process…
  • May 5, 2025
    RRF is how much a SIF reduces risk—calculated as the inverse of PFDavg. Easier to interpret than small probability values.
  • May 5, 2025
    PSM is the OSHA rule for managing hazardous chemicals. It overlaps with functional safety in SIS design and operation.