What You Should Know About Plumbing 
THE ESSENTIAL CONSIDERATIONS FOR SANITARY EQUIPMENT—VENTS, DRAINS 
AND TRAPS—WHERE TO LOOK FOR TROUBLE AND HOW TO TEST NEW PLUMBING— 
THE ADVANTAGE OF DECIDING ON FIXTURES BEFORE THE HOUSE IS COMPLETED 
by Mark Dean 
Photographs by Mary H. Northend and Ph. B. Wallace 
S O gradually has plumbing become a 
permanently large part of our econo¬ 
mics, that few people realize the important 
part it plays in our civilization. 
If the plumbing system were removed 
from any large city, its absence would quick¬ 
ly cause an intolerable pestilence; and as the 
plumbing of any house forms a complete 
unit, the collection of which units forms the 
city system, it would seem unnecessary to 
caution builders further as to the importance 
of giving this subject careful attention. 
A household plumbing system consists of 
one or more stationary fixtures, such as a 
basin, bath-tub, toilet, sink, laundry tub, etc., 
to which water is automatically supplied and 
from which waste is automatically removed 
upon the opening of a bib, the pulling of a 
plug, or some such simple operation. 
The piping may be divided into three 
classes; i. e. supply, waste and vent pipes. The 
supply pipes are quite small, seldom exceed¬ 
ing one inch in diameter; and are therefore 
easily installed, and may conveniently be 
placed between floors and partitions. If 
properly installed, which includes the neces¬ 
sary protection against freezing, the supply 
pipes seldom give trouble. The waste pip¬ 
ing is much larger then the supply piping, 
the main waste pipe of an ordinary house 
being four inches internal 
diameter; and when there 
is a water closet connected 
with it, it should never be 
smaller than four-inch 
pipe. The vent piping is 
also large and is con¬ 
nected directly to the 
waste piping, one of the 
main vents being a' full 
size continuation of the 
main waste pipe. The 
waste piping, unlike the 
supply piping, can have no 
valves or other fixtures 
which would stop the flow 
of waste. And yet, be¬ 
cause of the filth which 
gathers on its inner walls, 
there must be some sort of 
seal which will prevent 
gases from this piping 
escaping into the rooms of 
the house. To this end, a 
water filled bend in the 
pipe, called a trap is 
placed close to each fix¬ 
ture. A form of such trap is seen in nickel 
beneath the basin in the center illustration on 
page 38. This permits a free passage of waste 
and at the same time keeps all air in the pip¬ 
ing from escaping into the room by retain¬ 
ing water in the trap as shown in sectional 
view on page 50. This trap should have a 
vent at its crown as indicated by the dotted 
lines, otherwise it is apt to syphon the water 
out, which is equivalent to an open invitation 
to microbes. 
The writer's first lesson in syphonage was 
given many years ago by his father who took 
a crooked green onion stem, cut off both ends, 
filled it with water, and with a finger over 
each end, placed it over the side of a tub full 
of water as shown on page 51. When his 
fingers were removed, the water flowed from 
the tub through the onion stem until with his 
knife, he made a small puncture in the stem (at 
the point marked “A” in the diagram). The 
tendency of the water in each leg was to flow 
down; but for each to have flowed down would 
have created a vacuum within the onion stem, 
and the weight of the water was not sufficient 
to do this. This pressure was exerted by the 
greater weight of water in the outer leg of 
the stem and by as much of the water of the 
inner leg as was above the water level of the 
tub. Consequently the inner leg was over¬ 
balanced, and the water 
flowed from the tub. But 
wffien a puncture was 
made in the stem, the 
tendency of the pressures 
was no longer to create a 
vacuum but to draw in 
air, and so the stem was 
emptied and the syphon¬ 
age ceased. 
With these facts in 
mind it will be easier to 
consider the two main 
classes of plumbing sys¬ 
tems and their advantages. 
These are the non-ven- 
tilated and ventilated sys¬ 
tems. The former is not 
universally regarded as 
desirable. It consists 
merely of a main waste 
pipe that branches from 
the fixtures through traps 
placed close to the fix¬ 
tures. It is dangerous; 
first, because the air being 
confined and having no 
opportunity to circulate in 
A ventilated system with an opening at the 
roof, connecting with the bathroom fixtures 
and joined by a vent which is an extension 
of the main waste pipe. This arrangement 
of the traps and fresh air inlet insures 
proper air circulation 
A modern bathroom showing how the visible piping is restricted to but a few 
lengths of pipe, and this made attractive with nickel fittings and beautiful finish 
