How close must a union be installed from an MP regulator connected to rigid piping?

The correct distance for installing a union from a manual shutoff valve (or an MP regulator in this context) connected to rigid piping is 12 inches. This requirement is established to ensure that adequate space is available for maintenance and repairs, as well as to get a proper seal and prevent any potential leaks at the joint.

When unions are not installed at the appropriate distance, it can lead to difficulties in servicing the equipment. The 12-inch standard also accounts for minimizing stress on the piping system that can occur during thermal expansion and contraction. Proper spacing helps maintain the integrity of the connection, ensuring safe and effective operation of the piping system.

Understanding this distance is crucial for compliance with plumbing codes and ensuring the safety and functionality of the mechanical system involved.