The fitting may also be obtained with a waste opening at K. Such a waste could not be used, however, if the fitting were provided with the branch L, as this would mean that the same pipe served as both waste and vent, which is not right under any circumstances. A waste opening at K would provide a continuous vent with waste for a lavatory or sink.

All the special fittings shown in Figs. 143 to 146, and 152 to 155, with the exception of the vented T-Y of Fig. 143, are known as F and W combination vent, revent, and drainage fittings. They are of great practical value, and are coming into use to a considerable extent. As already indicated, they save a large amount of labor, reduce the number of joints, and make the work compact.

Figs. 152 155.   The Use of Special Water Closet Waste and Vent Fittings.

Figs. 152-155. - The Use of Special Water-Closet Waste and Vent Fittings.

Their use also allows continuous vents to be obtained under almost all conditions. It may be stated that these fittings constitute only a small part of the full line of such special fittings. Others, for use in connection with other fixtures than water-closets, will be seen elsewhere.

Owing to the nature of the waste which the water-closet receives, it should be surrounded with the best possible sanitary conditions. This is especially true, also, of the urinal. With our present knowledge and appliances, however, it is not now so difficult to install these fixtures under difficult conditions and still obtain good results, as it once was.

The water-closet should never be installed in a dark or unven-tilated place, for light and ventilation are absolutely necessary if this fixture is to be kept from becoming a foul nuisance. When properly provided for in these two respects, however, this fixture need prove scarcely more obnoxious than any other fixture. That this is true, is evidenced by the fact that the atmosphere of the modern well-lighted, well-ventilated bath room, provided with first-class fixtures and a properly constructed sanitary system, is scarcely more tainted than the atmosphere of the remaining rooms of the house.

The location of water-closets in cellars is always poor practice, though quite common in some sections. Whenever thus located, the water-closet compartment should be built with one of the cellar windows opening into it, in order that ventilation and light may be obtained as far as is possible under the conditions.

Whenever possible, the lighting of any room or compartment containing a water-closet or any other plumbing fixture, should be direct, rather than by means of light shafts. Exterior lighting, by means of which the benefit of sunlight may be obtained, is very desirable, as the action of sunlight is especially destructive to filth or germ life.

The natural ventilation of rooms through windows and doors is greater than commonly supposed, but when the water-closet is installed in any room, artificial ventilation is generally needed to keep the atmosphere of the room sufficiently pure. This matter is taken up in the chapter on local venting.

Considerable space has been devoted in this chapter to the venting of water-closets. A few additional remarks on the subject may be of value.

The water-closet is a more difficult fixture to siphon than any other to be found on the plumbing system. It is nevertheless true, however, that it may be siphoned. In a majority of cases, the water-closet trap is siphoned gradually, a few drops at a time, rather than completely at one such operation.

It is undoubtedly true that the venting of water-closets is sometimes demanded under conditions which actually make such provision unnecessary. For instance, when the water-closet is located close to its soil stack, on the top floor, it would be impossible in a plumbing system provided as the modern system is, with roof ventilation, to bring to bear upon its trap seal sufficient siphonic influence to produce even the smallest amount of siphonic action. Many other instances might be noted of water-closets located close to soil stacks in small plumbing systems, where it is really unnecessary to vent them. A water-closet located close to the foot of a stack serving a number of fixtures, or when located on a horizontal line, or when set at a distance from its stack, should always be vented, as siphonic influence on its trap seal under each of these conditions is sufficiently great to make its use necessary.

There are certain practices in connection with water-closet work which should not be followed, and which are of sufficient importance to demand special remark. It is a very common practice to connect the waste from other fixtures into the lead bend of the water-closet, rather than to provide a separate entrance into the stack for these fixtures. There is often a temptation to perform the work in this manner, as it certainly can be done at much less cost, and as it is sometimes difficult to do the work in the proper manner. Nevertheless, the practice is a poor one, for several reasons. In the first place, if the waste is thus connected, a stoppage in the lead bend will not only prevent the use of the water-closet itself, but also of any other fixture whose waste is connected into the bend.

The wiping of a waste into the lead bend cannot usually be accomplished without the forming of spines of solder reaching inside the bend, which will inevitably catch lint and paper and other materials entering the water-closet.

If, however, the waste of another fixture must be connected into the lead bend, it should never be connected into the heel of the bend, as shown in Fig. 156, or into the upright section. It should be connected into the horizontal part of the bend, and as high up on its circumference as possible.

Fig. 156.   Waste Connected into Heel of Lead Bend.

Fig. 156. - Waste Connected into Heel of Lead Bend.

The connection of the vent to the water-closet bowl has been mentioned elsewhere as a poor practice.