One would think that simple math would be sufficient when dealing with safety systems?  For the most part this is true, as today, simplified formulas are widely accepted for modeling safety instrumented systems.  The calculations used to help predict the performance of a specific safety design are derived from statistical formulas that ...

So you’re faced with the question of whether that trusty old transmitter you’ve been using as part of your safety shutdown system can meet the “prior use” requirements described in Section 11.5.3 of ANSI/ISA-84.00.01-2004 (IEC 61511-1 Mod).  Prior use, or Proven-in-use, is defined as a documented assessment showing ...