← Learn CONCEPTS · LEARN Functional safety From risk to SIL: how a safety function reduces risk in a demonstrable way. 1 pages · 8 min 1 Practitioner 8 min From risk to SIL: how a protection is sized SIL is not a label you pick, it is a level you calculate from the risk. Here is the chain of reasoning, from the hazard to the required integrity level — with the numbers.