This APP allows the SIL (PFD and RRF) calculation of a SIF modelled as input+logic solver+output. It also calculates the MTTFs as per ISA-84 formulae. The inputs for the calculations are the failure rates in FIT (the app provides a converter from flr/hrs) and a simple wizard to calculate Lambdas from PFD, Proof test interval and MTTF. Addittionally it calculates, given the HFT and the SFF, the architectural constraints supporting both IEC-61508 and IEC-61511 tables. The APP can save and restore csv backups.