Hey oneye14,My maths maybe a bit skew but I make PFD of 0.015 to be SIL 1.
bit more reading below - there is a lot more to understand !
https://www.crossco.com/resources/a...ntegrity-levels-for-your-process-application/
https://control.com/forums/threads/requirements-for-sil-3-system.45626/