(Published In 1891.)

In designing and executing the plumbing in the Plaza Hotel it was necessary to conform to the plans and conditions of the building, and to meet the requirements of the successive changes in construction and system that accompanied the changes made in its owners, architects, builders, and contractors. William Paul Gerhard, C. E., of New York City, was consulting engineer for the drainage and ventilation, and S. & A. Clark, also of New York, were the contractors for the plumbing, various detached features of which are illustrated in this and succeeding parts.

The water supply for the hotel is received from the city mains, passes through Worthington meters, and is delivered through 3-inch pipes A and B from the Fifty-ninth Street and the Fifth Avenue mains respectively. These pipes deliver through branches C C and double ball cocks into the boiler-plate tank D, which rests on the basement floor and affords some storage in case the city mains are shut off, besides preventing a draft on the meters.

PLUMBING IN THE PLAZA HOTEL, NEW YORK CITY.

E is a 6-inch suction pipe connected to all the pumps, and F is a 2-inch emptying pipe; J is a 4-inch overflow pipe which empties freely into the bell-mouthed pipe I. The latter is trapped into the sewer. The top of pipe J has a hinged flap plate K, to which a heavy ball float L is connected by a long arm. When the water in the tank is below the overflow level this float acts as a weight to hold the cover down, tightly closed, and to prevent any discharge of gas, cellar air, etc. above the water. When the tank is nearly full of water the ball L acts as a buoy to open the flap and permit overflow through J. Ordinarily the valve H is open, and all the street water is first received in tank D, but by closing H the pumps may be supplied from the main A directly through branch G. The pumps are also similarly connected with pipe B.

Figure 2 shows the connections of the pump suction and delivery pipes. A A are two Worthington pumps, whose suction pipes B B are connected with the 6-inch header D, which may be supplied from any or all of the branches, E, F, and G. E is a 6-inch pipe to suction tank D, Fig. 1. B is a 3-inch pipe to the cistern which receives the rainwater from the roofs, etc., and G is a 6-inch pipe connected direct to the city mains. The pump-delivery pipes C C are connected to the 4-inch headers H H, which have the branches N N, etc , with valves L L, etc., so arranged that either or both pumps can deliver through anyone or more of the pipes O, P, Q, R, and S, four of which lead to the different roof tanks, and one to the elevator tank. All the pipes are jacketed to prevent the condensation of moisture on their surfaces.

Figure 3 shows the pipe A supplying steam to the pumping engine cylinders B B. When the tank is full its supply pipe is closed and the action of the pump develops pressure in it. This pressure operating on the diaphragm of a pump regulator, produces a pull on chain C which raises the weighted lever D and closes valve E, thereby shutting off the steam and stopping the engine. When the water level is lowered in the tank the weight of W opens valve E, and the pump starts up and so on. F is a throttle valve for independently controlling the steam.