Abstract: The breathing air system is made of a pressurized breathing air source, a continuous loop air conduit connected to the pressurized breathing air source for maintaining the breathing air at a defined pressure, a first isolation valve located between the pressurized breathing air source and the continuous loop air conduit, a first splitter is located between the first isolation valve and the continuous loop air conduit, a second splitter is connected to the continuous loop air conduit, a first auxiliary air conduit segment is connected to the second splitter, a second isolation valve connects to the first auxiliary air conduit segment, a reserve manifold is also used and a second auxiliary air conduit segment communicates between the second isolation valve and the reserve manifold to distribute breathing air to at least one reserve manifold from at least two directions wherein the breathing air is grade “D” or better.