For residential piping systems that lack a readily accessible open burner on an approved appliance with an input of 400,000 Btuh or less, purging of air from the piping system shall be conducted in accordance with what?

The correct answer pertains to Annex H of the B149.1 Code, which specifically addresses the procedures for purging gas lines in situations where an approved appliance does not have an accessible open burner and has an input of 400,000 Btuh or less. This annex provides detailed guidelines on how to safely purge air from the system to ensure proper gas flow and minimize risks associated with gas installations. It is essential for technicians to follow these specific procedures for maintaining safety and compliance in the installation and maintenance of gas piping systems.

The options referencing other sections or annexes of the B149.1 Code do not cover the particular requirements for purging in this context, which is why they are not applicable here. Understanding the distinction between the various sections of the code and their specific applications is crucial for technicians handling gas systems to ensure they adhere to safety standards and regulations.