Which engineer is called piping engineer mechanical or civil?

Mechanical engineer design the whole lines including connections, valves, bends, pumps, welding, ect, and that is depending on loss calculations, and the system function. In the other hand civil engineer design the structure, and the supports that will carry this system whether it was a steel structure, or a concrete one. 

Sometimes, mechanical engineer do both of them based on the difficulty of the holding structure.