In the design of the interior arrangements, the value of a generous supply of stairways was appreciated, in order that all parts of the structure might be made readily accessible, especially in the boiler house section.  In the boiler house and machinery portion of the plant the stairways, railings, and accessories are plainly but strongly constructed.  The main stairways are, however, of somewhat ornate design, with marble and other trim work, and the railings of the main gallery construction are likewise of ornate treatment.  All exterior doors and trim are of metal and all interior carpenter work is done with Kalomein iron protection, so that the building, in its strictest sense, will contain no combustible material.

[Sidenote:  Chimneys]

The complete 12-unit power house will have six chimneys, spaced 108 feet apart on the longitudinal center line of the boiler room, each chimney being 15 feet in inside diameter at the top, which is 225 feet above the grate bars.  Each will serve the twelve boilers included in the section of which it is the center, these boilers having an aggregate of 72,000 square feet of heating surface.  By these dimensions each chimney has a fair surplus capacity, and it is calculated that, with economizers in the path of the furnace gases, there will be sufficient draft to meet a demand slightly above the normal rating of the boilers.  To provide for overload capacity, as may be demanded by future conditions, a forced draft system will be supplied, as described later.

As previously stated, the chimneys are all supported upon the steel structure of the building at an elevation of 76 feet above the basement floor and 63 feet above the grates.  The supporting platforms are, in each case, carried on six of the building columns (the three front columns of two groups of boilers on opposite sides of the center aisle of the boiler room), and each platform is composed of single-web plate girders, well braced and surmounted by a grillage of 20-inch I-beams.  The grillage is filled solidly with concrete and flushed smooth on top to receive the brickwork of the chimney.

Each chimney is 162 feet in total height of brickwork above the top of the supporting platform, and each chimney is 23 feet square in the outside dimension at the base, changing to an octagonal form at a point 14 feet 3 inches above the base.  This octagonal form is carried to a height of 32 feet 6 inches above the base, at which point the circular section of radial brick begins.

The octagonal base of the chimney is of hard-burned red brick three feet in thickness between the side of the octagon and the interior circular section.  The brick work is started from the top of the grillage platform with a steel channel curb, three feet in depth, through which two lines of steel rods are run in each direction, thus binding together the first three feet of brickwork, and designed to prevent any flaking at the outside.  At a level of three feet above