Side Walls.

glass breaks and none of these are at hand, always shut off the water, or bottom, valve first. By doing this and using care one need not get burned. If steam is shut off first, look out.

When building a bridge wall, put the fire-brick face as shown in Fig. 14.

When the brick on the face are laid up square, the tools used in cleaning the fire will gradually knock off the

top course, and after a time the whole bridge wall disintegrates. Putting in bricks as shown locks the top brick effectually and makes a durable wall.

When building the side walls the same course should be taken in putting in the fire-brick at the furnace as shown at the bottom of the bridge wall. This makes

Fire Brick Arch.

repairs quickly and cheaply done. This is shown in Fig. 14. These are headers above the clinker line, then a stretcher for binding, then all headers, but the top bricks are wedged so as to have the top ones embedded.

This form of construction accomplishes two things: The bricks at the bottom burn out, and they can be taken out up to the stretcher, which will fall out, leaving the remainder of the wall intact. The bottom brick and stretcher can be replaced without the necessity of taking down the whole face.

Where air space is left, it should be 3 or 4 inches next to the outer course of brick.

Fig. 16. Making a Fire Brick Arch.

The walls should be sloped away from the boiler as shown, leaving a space not less than 3 inches from the shell until the wall closes in to the boiler.

Fig. 16 is a design for making an arch with fire brick.

It consists of an iron form, as shown by the heavy line which can be either of wrought iron bent into proper shape for any length or radius of arch desired, or it may be of cast iron.

The brick are built into it tight and the structure is set into place.

It can be used over doors or at rear of boilers.

As the metal is protected by the brick, the arch will last until the brick are burned out, if no mortar is put between them; that is, if the brick are laid solid.

Furnace Plates.

For a plate over the furnace the style shown in Fig. 17 is the best, if cast iron is used. This was designed by the Hartford Steam Boiler Inspection & Insurance Company.

With this form the iron next the fire can expand until the spaces are entirely closed, and the plate will still keep its shape. The casting can be made in the form of a box, so as to take in the sides and top of the door; but it should all be serrated, as shown, on the side towards the fire.

Shell boilers are usually supported by two lugs on each side. The rear lug should rest on rollers. It would

be a better plan to put up columns and channel bars and hang the boilers from these, after the manner in which tube boilers are supported, so as to have them entirely free from the brickwork. This would make the boilers more expensive, and as one reason for putting in this type of boiler is the low first cost, this form of support is rarely attempted.

Fig 14 shows a pipe leading from the safety valve for a distance and then turned up. This is unsafe unless there be a firm support under the ell. Wherever there is an open end just beyond an ell, the ell should be well supported. Pipes like this will break open the valve case when blowing off. One man had one ear partially torn off

Floor Plates.

at one time with a 34-inch drain pipe put up in a similar

manner.

There should also be a drain at the ell. The better plan is not to put any pipe from the safety valve, but let it blow directly into the boiler-room. If this is done, one can always see just what the valve is doing.

At one place where the pipe from the safety valve led out of doors in a horizontal direction, the valve leaked,

Fig. 18. Floor Plates.

and one cold Saturday night the pipe filled with ice. The fires were banked, but during Sunday night the boiler got to making steam, and while the safety valve did its duty the steam could not get away, and an explosion was the result.

For a floor for boiler-house put in Portland ceinent concrete. Where no teaming is to be done on it, 4 inches will be sufficiently thick. Where teams bring in the coal it should be 6 inches. There should be a drain at the

Draining of Floors.

corner of each boiler, leading down into an underground drain.

The floor should slope in all directions to this drain. When this is done all water flows away quickly and the floor can be washed at any time. There should be a 1inch water pipe of cold water brought to the boiler-house, if the pumps are in another place, and plenty of 3/4-inch hose on hand for wetting ashes and washing the floor.

In front of the boilers the floor should be of iron, as this will not wear out with the shovel and will stand hot ashes.

Front of boiler put down a floor of iron plates like Fig. 18. These plates are 3/4 inch thick, diamond tread on top and ribbed on the bottom. They are 24x30 inches, and can be laid in two rows, so as to make the iron floor 4 or 5 feet wide, as desired. They are laid in soft cement, and should be hammered down to place, when they will stand all sorts of hard usage.