MCC-NH Gas Fitters Practice Exam

Where is the shut-off valve typically located on a dual regulated LP system?

1. At the appliance connection

2. At the meter set

3. At the tank and the inlet of the second stage regulator

4. At the first stage regulator

The correct answer is: At the tank and the inlet of the second stage regulator

In a dual regulated LP (liquid propane) system, the shut-off valve is typically located at the tank and the inlet of the second stage regulator. This is essential for ensuring safety and proper handling of the gas system. The reasoning behind this placement involves both safety and system management. Having a shut-off valve at the tank allows for immediate access in case of emergencies, such as a leak or the need for maintenance. It enables gas supply to be stopped right at the source, providing a first line of defense in hazardous situations. Meanwhile, placing another shut-off valve at the inlet of the second stage regulator permits isolation of the downstream system, ensuring that the gas flow can be controlled more effectively during maintenance or repair work without affecting the entire propane supply. The other locations mentioned in the potential answers, while relevant to gas supply systems, do not provide the same level of safety and control. For instance, having a shut-off valve only at the meter set or at the appliance connection would not allow for the same comprehensive control over the system, especially during emergencies or maintenance operations. Additionally, placing it solely at the first stage regulator may not provide the same operational safety or isolation capabilities as having valves in both specified locations.