PHA BPCS IPLs

According to IEC61511, you are not allowed to take more than one IPL from the BPCS (zero IPLs if the initiating event is the BPCS). The only exception would be if you have 2 completely independent BPCS functions. This includes the BPCS controller. Just having a separate sensor and a separate valve is not good enough.

Every plant I’ve worked at has broken this rule. Some intentionally and some unintentionally. What is everyone else doing? Is this the norm? Is it reasonable to break this rule?

Personally I think requiring a separate controller is excessive especially if your plant has good administrative procedures around BPCS IPLs.