What action must be taken when replacing sprinkler system components affecting 20 sprinklers or less?

The correct choice is to follow NFPA 13 guidelines when replacing sprinkler system components affecting 20 sprinklers or less. NFPA 13 outlines the installation, design, and maintenance standards for sprinkler systems, including the proper procedures and specifications for replacing components. This guidance ensures that any modifications to the system maintain its effectiveness and comply with the necessary regulations.

Although guidelines from NFPA 25 pertain to the inspection, testing, and maintenance of water-based fire protection systems, NFPA 13 provides the detailed criteria and requirements for installation and modification. Following NFPA 13 when replacing components helps ensure that the system continues to function as intended and adheres to safety standards.

Documentation of the replacement is indeed important but is not the only requirement. Simply documenting the replacement without following the established guidelines could lead to non-compliance with safety standards, potentially compromising the performance of the fire protection system. Therefore, it's crucial to adhere to NFPA 13 guidelines in this scenario.