Redundancy in safety systems refers to having

• A. Multiple identical components performing the same function
• B. Only one component performing a function
• C. Diverse components performing different functions
• D. Active components without backups

Answer: (A)

Redundancy means having backups that can take over the function if the primary element fails. When there are multiple identical components performing the same function, the system keeps that safety capability even if one component deteriorates or fails, so overall reliability is increased. The safety function is only at risk if all copies fail, which is much less likely than a single component failing. This is the standard way to ensure an uninterrupted response in critical systems.

Having only one component provides no backup, so it isn’t redundant. Using diverse components performing different functions is a different strategy called diversity (used to reduce common-cause failures, not redundancy in the strict sense). Active components without backups obviously lack redundancy since there’s no alternate path if the active part fails.