System should be observed in the arrangement of valves so that in case of emergency, without loss of time, water can be cut off from the line affected. A system of valving should consist not only of controlling each separate line and branch in the supply system with a valve, but also in so arranging them that they will be accessible, and that valves for like purpose will bear the same relative position in relation to the system. For instance, each distributing main* should be valved close to where it is connected to the distributing manifold; each distributing branch+ should be valved where it is connected to the distributing main, and each fixture branch# should be valved where it is connected to the distributing branch. Where a number of valves are clustered together, as for instance, near the distributing manifold, each valve should be provided with a brass tag stating what lines of pipe it controls, or else stamped with a letter or number which, by referring to a valve chart, will tell the line of pipe controlled.

Fig. 96 - End Elevation

Fig. 96

Emptying-Pipes And Valves

In all systems of piping provision should be made to empty the pipes when the water is shut off. This is usually accomplished by placing valves in the distributing and circulating mains just above the distributing manifold and connecting them to emptying pipes discharging into a water supplied sink. The manner of connecting and valving emptying pipes can be seen in Figs. 95 and 96.