What should appliances and equipment not involved in the pressure test be?

The correct answer highlights that appliances and equipment not involved in the pressure test should be isolated or disconnected from the piping. This practice is essential for several reasons. First, isolating the equipment ensures that only the sections of the piping relevant to the pressure test are subjected to testing conditions. This prevents any potential damage to appliances or equipment that may not be designed to withstand the pressures exerted during the test.

Furthermore, disconnection from the system eliminates the risk of false readings or leaks that could involve the appliances, which might compromise the integrity of the test results. Ensuring that only the designated piping is being tested allows for accurate identification of weaknesses or failures in the system, ensuring the safety and functionality of the overall installation. This procedure is a standard practice in maintaining compliance with safety regulations and standards in plumbing and gas-fitting operations.