Floor drains, when used in cellar or basement, should be connected to the leader side of a rain leader trap wherever it is possible. Some sanitary engineers go so far as to say that floor drains should never be used, their objection to them being that the floor is not washed often enough to furnish sufficient water to maintain a water seal at all times against sewer gas ingress, and their argument is well taken, but floor drains in a basement are very convenient, and should be part of a well-installed sanitary sewer system.
In case of a seepage of water through the foundation walls, during a rainy period, it is well to be provided with some means to carry the water away quickly, without having to resort to the laborious practice of pumping.
The evils of a floor drain are not so much due to their inefficiency, as they are to the care taken of them. The cemented floor basement of the modern home today is just as important to be kept clean as the bathroom, and the thorough housekeeper takes just as much pride in it, and realizes the necessity for having it so from a sanitary standpoint.
The old method of installing a floor drain or floor outlet which consisted of placing a running trap in the line of drain pipe to the catch-basin, and running a piece of pipe to the floor level and simply closing the opening with a bar strainer grate is wrong. The grate, even when cemented into the hub end of the pipe, will in time become loosened, and dirt and other rubbish will soon clog up the trap and render it useless.
As before said, the great objection to a basement floor drain in the ordinary house, is that there is seldom sufficient water used on the basement floor, to maintain a perfect water seal in the trap. To neglect to see that the floor drain trap is not always -filled with water and to argue against its installation on that point is wrong.
Floor drains should never be used without a back-water valve, which will prevent sewer water from backing up into the basement. A number of different styles of floor drains are. shown, which are built on the proper lines. The one shown in Fig. 9 is a combination floor drain and back-water gate valve. This accessible cleanout cellar drain flushing cesspool and back-water gate trap valve combination has much to be commended. It has a hinged strainer, through which seeping and floor waste water finds a direct outlet to the trap and sewer. The trap has a deep water seal, which is always desirable, and is always provided with a brass back-water gate valve or flap-valve which will not rust and which will close and hold tight against a back flow from the sewer. It also has a tapped opening to which a water supply pipe can be attached, and by means of a valve being placed on the pipe at some convenient point, the drain trap can be throroughly flushed and cleansed by simply opening the valve for a few minutes at a time.
Another method oftentimes used to provide for a floor outlet to sewer is to run a piece of iron soil pipe from the trap on the sewer to the floor level, and to caulk into the hub of the pipe a brass ferrule or thimble with a brass screwed cover, which is screwed down tight against a rubber gasket, as shown in Fig. 10. An outlet of this character is only opened when occasion demands, by unscrewing and removing the cover until its need is past.
In Fig. 11 is shown an extra heavy cesspool suitable for barns, carriage room and places of like nature. The top is sixteen inches square, the body ten inches deep and has a four-inch outlet, suitable for caulking into the hub of a four-inch iron sewer pipe. The top cover or grating is heavy enough to permit of horses, wagons and carriages passing over it. The second grating or strainer is of finer mesh, which catches any obstacles which might clog up the sewer, it can be lifted out by the knob and easily cleaned at any time. The deep water seal in this trap is one of its good features, the bell or hood not only serves to maintain a water seal, but where used in stables is a shield over the outlet to prevent oats or grain of any description which might fall through the second strainer from getting into the sewer.
Care should be taken to prevent the bottom of the cesspool from filling up with fine strainings.
Fig. 12 is a combination floor strainer and backwater seal and is used in the hub of a sewer pipe which extends down to the trap placed in the sewer run. The rubber ball prevents the flooding of the basement from backing up of water, by being floated to seat above.
In Fig. 13 is shown a floor drain and trap, designed especially for hospital operating rooms and other places where it is desirable not only to cleanse thoroughly the floor, but also to remove all sediment from the trap itself for obvious sanitary reasons. The trap is of cast iron, and is enamelled inside. This gives it an impervious and smooth surface and prevents the trap from becoming coated and slimy. This trap is provided with heavy brass cast flushing rim and has a brass removable strainer.
In the sectional view is shown the method by which the water supply is connected to both the rim and trap, by means of which not only every portion of the body may be cleansed, but also all sediment removed from the jet inlet at the bottom.
The trap is built especially to maintain a deep seal and is three inches in diameter.