When replacement of sprinkler system components affects more than 20 sprinklers, what must be followed during installation and testing?

The requirement to follow NFPA 13 during the installation and testing of sprinkler system components when more than 20 sprinklers are affected is based on the specific guidance provided by this standard. NFPA 13 outlines design and installation criteria for sprinkler systems, ensuring that any modifications or replacements made to the system maintain its intended reliability and performance.

When more than 20 sprinklers are replaced, it is essential to adhere to NFPA 13 because the changes may significantly affect the system's hydraulic calculations, spacing, and overall effectiveness in fire suppression. Ensuring compliance with NFPA 13 guarantees that the system will continue to function as intended in the event of a fire, complying with the regulations that govern sprinkler design and installation standards.

Other standards listed, such as NFPA 25, mainly focus on inspection, testing, and maintenance, rather than the installation and design process. NFPA 307 pertains to the fire protection for marine vehicles, which is unrelated to sprinkler systems. NFPA 72 deals with fire alarm systems and their components. Hence, only NFPA 13 is directly applicable when significant changes to the sprinkler system are made.