The Secret of Silent Plumbing 
MINIMIZING THE NOISES INCIDENT TO THE FLOW OF WATER THROUGH THE PIPES BY PROPER 
INSTALLATIONS AND MODERN FIXTURES—THE EQUIPMENT FOR FIOUSES OF VARIOUS SIZES 
by Edward C. Cuthbert and G. William Isley 
A NY of a hundred and one things may contribute their mite 
or their mightiest to noisy plumbing. Actually, and for¬ 
tunately too, but a few of these many defects occur in the usual 
installation. But as the source of annoyance may be the result 
of one defect in one house and something else in the next house, 
until in a hundred and one houses we find them all, how are 
we to guard against hissing, hammering, gurgling, singing and 
all the rest of the evils, but by making our plumbing installations 
proof against each 
and every one? 
By cautioning 
architects and 
plumbers before and 
at the time of in¬ 
stalling new plumb¬ 
ing we can be rea¬ 
sonably sure of 
avoiding the main 
causes of annoy¬ 
ance. If the plumb¬ 
ing in a house now 
built and occupied 
is defective the sug¬ 
gestions here will 
possibly indicate the seat of trouble and point a way to eliminat¬ 
ing or at least modifying the nuisance. 
The hiss or rumble of water in a supply pipe, which occurs 
when a faucet is opened, is quite common. It may be due to 
small pipe sizes, improper supports, high pressure, poor location 
of piping, undersized stop cocks or valves, and so on. 
For a house with one bathroom, kitchen and laundry fixtures 
and one or two lavatories in bedrooms, the main supply pipe 
should not be less than ^ 4 -inch in size. One-inch is even 
preferable if the pressure is less than thirty-five or forty 
pounds. If the pressure is lower than this the supply pipe 
should be one-inch, anyway—not especially to avoid noise, but 
to provide an adequate volume of water. The size should be in¬ 
creased one size for each extra bathroom — that is, ij4 inches, 
1 1 /-2. inches or 2 inches. Pipe of * 4 -inch size is too small except¬ 
ing for branch connections to single fixtures. 
The pipe to the kitchen range boiler should be ^ 4 -inch in a 
house having one bathroom and i-inch for two or three bath¬ 
rooms. For a larger number of fixtures a separate hot water 
heater with storage tank is usually installed. The pipes to the 
bathroom should be not less than ^4-inch, and if the bathroom 
contains a needle and shower bath, i-inch is desirable. The 
bath tub should have ^4-inch supply pipes; the lavatory R>-inch ; 
the closet ^4-inch; the kitchen 
sink 24 -inch; the pantry sink 
p2-inch ; and the laundry tubs 
24 -inch. These sizes should 
be maintained right up to the 
connection with the fixtures 
even though the actual valves 
or faucets of the fixtures are 
smaller. 
Water flowing through a 
pipe at a high velocity will 
not only hiss within the pipe itself 
but at times cause the pipe to vibrate. 
This is especially true of small pipes. 
The resulting noise is transmitted to 
the timbers, partitions and flooring 
until the whole responds like the 
highly-strung sounding board of a 
piano. Proper supports, placed not 
more than five or six feet apart and 
deadened to prevent the transmis¬ 
sion of sound, are effective remedies. 
A layer of hair felt placed between 
the pipe, with its supporting clamp, 
and the woodwork is a good way to 
stop this trouble. 
At times it is advisable to cover 
pipes with a non-conducting cover¬ 
ing to prevent freezing. This covering 
can be purchased in a manufactured 
form. It is sold in lengths of three feet. It also prevents the 
escape of the sound of running water within the pipe. 
When wrought iron pipe is used for water supply piping (and 
to-day in ninety-nine per cent of houses it is employed) abrupt 
connections cannot be avoided. Lead pipe can be bent into easy 
curves which do not retard the flow of water, while the lead 
itself is a poor conductor of sounds or vibrations. Lead has this 
in its favor even with- a much higher cost as a disadvantage. 
A good pressure of water—between twenty-five and seventy- 
five pounds — is desirable. Higher pressures than these are apt 
to be troublesome and noisy when water is drawn. High pres¬ 
sures can be lowered and controlled by installing a pressure re¬ 
ducing valve, through which all water to the house must pass. 
Water is practically incompressible. With a high pressure the 
sudden closing of a faucet will produce “water hammer that 
is, the momentum that the flowing water has attained when a 
faucet is open will expend itself in hammering within the pipe 
when the velocity is suddenly checked by the closing of a faucet. 
Air chambers are used as cushions to prevent or reduce water 
hammer, and to be effective they should be at least 2 inches or 
2)4 inches; or better, 3 inches 111 diameter and three or four feet 
long. Sometimes they are placed on the water pipe where it 
enters the building. Water is more or less charged with air 
which is released when the pressure is reduced. Air chambers 
depend upon this released air for their effectiveness. If the air 
within the chambers was not continually renewed they would 
become waterlogged and useless. It is best therefore to place 
air chambers at the extreme end of the pipe line, where the 
pressure is lowest. It is not 
always possible to do this, as 
the end of the supply pipe is 
usually in the upper floors of 
the building. A convenient 
point to place air chambers is 
on the supply pipe just in¬ 
side the foundation wall. 
To insure the effective¬ 
ness of air chambers, means 
should be provided to re- 
A layer of felt between pipe and wall deadens 
vibration noises 
At the left is the core of a flat-way stop cock, less desirable than the round-way in 
the center. A complete round-way is at the right 
An air chamber that is re¬ 
charged by closing cock a and 
opening cock b 
( 31 ) 
