Which of the following situations require re-acceptance testing to be performed?

Re-acceptance testing is necessary in various scenarios to ensure that the fire alarm system continues to function as intended after modifications. When smoke detectors are added or removed, it directly affects the system's ability to detect smoke effectively and maintain the intended coverage for the protected area. Testing after making such changes ensures that the detectors are properly integrated into the system and will perform reliably during an actual fire event.

Similarly, alterations to control relays can impact the activation of alarm devices or other interconnected systems. Control relays are crucial for the correct signaling of alarms, so any modifications made to these components require re-testing to confirm that the system responds appropriately under emergency conditions.

Additionally, any changes made to system hardware, such as replacing or upgrading components, can alter the dynamics of how the fire alarm system operates. It is vital to perform re-acceptance testing to validate that all hardware is functioning correctly and maintains compliance with safety standards.

Since all three situations—alterations to smoke detectors, control relays, and system hardware—can significantly impact the overall functionality and reliability of the fire alarm system, re-acceptance testing is essential in each of these cases. Thus, an assessment that encompasses the need for testing after each of these types of changes ensures thoroughness