How long must complete unalterable records of tests and operations be kept?

• A. 1 year
• B. 3 or more
• C. 5 years
• D. 7 years

Answer: (B)

The key idea is maintaining an auditable trail of testing and system operation for a minimum period. Complete unalterable records are kept to prove that tests were performed and that systems operated correctly over time, and to preserve the integrity of those records so they can be relied on in audits or investigations. The required minimum is three years, which provides a sensible window to document ongoing maintenance, testing events, and any issues that may arise after installation or service.

Keeping records in an unaltered state is important because it prevents tampering or retroactive changes that could obscure the actual test results or operational history. This can be done with secure, tamper-evident storage—whether physical copies or protected digital logs with timestamps and proper access controls. While some organizations may opt to keep records longer for business reasons, the minimum standard aims for three years to meet regulatory and practical needs.