Which statement is true regarding the preparation for testing according to NFPA?

The statement regarding specific isolation methods being outlined is true according to NFPA guidelines. The NFPA (National Fire Protection Association) emphasizes the importance of safety and compliance in preparation for testing. This includes detailed procedures for isolating systems to ensure that they do not pose a hazard during inspections or testing.

Isolation methods are critical as they allow for the safe assessment of equipment without risk of accidental activation or pressure release, ensuring both the safety of personnel and the integrity of the systems being tested. These procedures are outlined clearly in NFPA standards to promote uniform and safe practices across the board.

In contrast, while other choices touch on important aspects of safety and preparation, they either oversimplify the requirements or misrepresent the comprehensive guidelines established by the NFPA. Visual preparation alone is not sufficient, air pressure testing is not universally mandatory, and disconnection of all appliances is not always required in every context. The key takeaway is the importance of thorough and specific isolation methods to mitigate risks during testing procedures.