The continuous venting of fixture traps is sometimes known as "venting in the rough," the origin of the phrase being easily understood after referring to Plate 27, the connections for which are almost wholly made when the roughing is installed. In many towns and cities double apartment houses, with two flats on each side, are very common, and in buildings of this kind the continuous-vent principle may be applied to very great advantage, after the manner shown in Plate 27.
This same style of work may be used in many other buildings where the plumbing fixtures are on two floors, and assembled in a manner similar to the assembling of the fixtures in Plate 27. So long as the stack serves fixtures on two floors only, it does not matter whether the two floors are consecutive, or whether one or more floors intervene between the two on which the fixtures are located.
Plate XXVII. Continuous Venting For Two-Floor Work
Continuous Venting for Two-Floor Work
In double apartment houses the rooms are generally so planned, and the plumbing fixtures so located, that the stacks may be carried up in the wall which divides the two sides of the building. When so arranged, only half the number of vertical stacks is needed that would otherwise be necessary.
Thus, one stack may serve all four kitchen sinks in the four-flat apartment building, the four fixtures being backed up to each other in pairs, on opposite sides of the division wall or partition, under which conditions the system shown in Plate 27 may easily be applied.
The main waste and vent stacks are run in the usual manner, the two being connected above the highest fixture, and below the lowest waste entrance. A novel departure is made in connecting the traps of the two fixtures on the upper floor. Instead of connecting them into the waste stack in the ordinary manner, they are connected into the line that would ordinarily be the main vent stack.
As the upper-floor fixtures are not connected into the waste stack, the line of pipe above the waste fitting of the lower floor is a vent, and into this vent line the vent line from the other two fixtures connects.
In this style of work, neither vertical stack is entirely a waste stack, or entirely a vent stack. While altogether unlike the regular two-floor work, this style of work is perfectly legitimate.
It can be applied only to two floors, for the third-floor fixtures would have to waste into one or the other of the two vertical stacks, and that stack could no longer be used as a vent line.
A comparison of this plate with Plate 28 will show that this statement must be true, and it will also show that the use of the connections such as Plate 27 shows, calls for much less outlay in stock and labor per fixture than does the ordinary method of continuous venting.
As compared with crown venting, the work of Plate 27 calls for far less labor and considerably less stock.
If crown venting were employed, the main vent line would have to be run and connected with the waste stack above and below, as shown.
A fitting on the main vent line would be required at each floor, while the waste fittings would remain the same.
Separate vents would have to be run from the crown of each trap, necessitating, in the case of lead work, a wiped joint on the trap and another at the vent fitting. This comparison will show that the labor involved in the continuous venting of two-floor work of the style shown in Plate 27 is very much less than on the same system installed according to the ordinary methods of crown venting.
While in general it would seem that continuous venting can be done with less labor, it cannot so often be done with less stock, but its advantages are so great that it would appear that in the higher grade of construction, at least, it would soon come into general use. At the present time its use is demanded by some few city ordinances, and recommended by others.
There is this to be said concerning its adoption: the continuous vent cannot always be applied, and in some cases it could not be applied without considerable additional cost.
Owing to these conditions it would seem unwise to attempt to demand its use without regard to circumstances surrounding the fixture, but at the same time, much good work would be provided for in the future, and a long step taken in advance, if plumbing ordinances would call for the use of continuous venting wherever practicable.