CSLB Class B General Contractor's License Practice Exam

What type of valve can shut off water to an entire building?

1. Pressure relief valve

2. Full bore valve

3. Gas cock valve

4. All of the above

The correct answer is: Full bore valve

A full bore valve is designed to allow for unrestricted flow of water through its opening. This type of valve can be used to isolate the water supply to an entire building, allowing for maintenance or repairs without needing to shut off water to other connected systems. Full bore valves typically have a larger diameter opening than other valve types, facilitating quick and efficient shutting off of water flow. In contrast, a pressure relief valve serves a specific function to relieve excess pressure in a system, preventing damage to pipes and fixtures. It is not designed for isolating the supply of water to a building. The gas cock valve is used to shut off the gas supply, and thus, it is not applicable to shutting off water. The option indicating 'All of the above' cannot be correct since not all the valves mentioned serve the same purpose related to shutting off water to a building. Thus, the focus on the full bore valve explains its suitability for shutting off water supply comprehensively.