This section is from the book "American Plumbing Practice", by The Engineering Record. Also available from Amazon: Plumbing: A working manual of American plumbing practice.
The Demilt Dispensary is at Second Avenue and Twenty-third Street, New York, and in its basement six rain baths and one tub have lately been placed, with provision for increasing the number. The rooms are arranged as shown in Fig. 6 and are open to men and women on alternate days, a charge of 10 cents each being made, unless the bathers are unable to pay,when free tickets are issued to them. The rooms are lighted by gas and heated by steam.
The six rain-bath compartments are duplicates and fitted the same as the Baron de Hirsch baths except that the bath proper is paneled with 1 ¼ - inch blue-veined Italian marble slabs, and the dressing-rooms with wood painted with five coats of Aspinall's special bath enamel. The floor of the office and corridor is of wood, that of the bath being of cement.
Unlike the system adopted for the Baron de Hirsch baths,the douches at this bath have no bibbs, and are not under the control of the bather, but are operated from a valve board in the office. Figure 6 is a general floor plan showing a hot-water heater A, the 200-gallon boiler B, and the valve board C; 1, 2, 3, 4, 5, 6 are the rain baths and 7 is a room for invalids, children, etc., with a high, enameled iron, rolled-edge tub T. Figure 7 is a section at Z Z, Fig. 6. When a bather is undressed he touches the electric button and the attendant at the valve board mixes the hot and cold water and turns it in his douche, afterwards further regulating the temperature if requested to. When the bather has finished he again presses the button and the water is turned off. Figure 8 shows the heating, storing, mixing, and delivering arrangements. Cold water under city pressure is delivered to the boiler B through the 2-inch pipe E; circulates to and from the heater A through 2-inch pipes F F and is delivered through 2-inch pipe G to the 2½ - inch heater H (on the valve board C, Fig. 6). Cold water is also delivered through the pipe D to the heater I. and a branch J from each of these headers unites in the mixing chamber K to form a pair for each of the six rain baths, the numbers of which are painted between them. The water is mixed by valves M M, and when the special thermometer N indicates the required temperature (normally ico° Fahr.), valve O is opened and the water is delivered through pipe L to whichever bath compartment is indicated by the electric annunciator P, which rings a bell and raises a pendulum bob attached to the corresponding numeral above. A is a safety valve, R an emptying pipe, and S S S pipe legs supporting the boiler B. T is a drip pipe for emptying lines I I, etc. Meter experiments by Mr. Gerhard showed that with both cocks open the bathtub was filled to within 5 inches of the overflow (45 gallons) in two minutes, and that the douche with both valves half open, under the same water pressure, about 20 pounds discharged about 7.1 gallons per minute, so that, allowing three minutes douche for each bather, not quite half a tub-ful of water is used. Probably, however, it is used much more lavishly in practice, as the attendant states that the 200-gallon boiler does not suffice well for more than six simultaneous baths.