lly connected with one lead waste pipe one and a half to two
inches in diameter, with one trap for all the tubs.

=Bath Tubs.=--Bath tubs are made of enameled iron or porcelain, and
should not be covered or inclosed by any woodwork. The branch waste
pipe should be trapped and connected with the main waste or soil
pipe. The floor about the tub in the bathroom should be of
nonabsorbent material.[19]

=Refrigerators.=--The waste pipes of refrigerators should not connect
with any of the house pipes, but should be emptied into a basin or
pail; or, if the refrigerator is large, its waste pipe should be
conducted to the cellar, where it should discharge into a properly
trapped, sewer-connected and water-supplied open sink.

=Boilers.=--The so-called sediment pipe from the hot-water boiler in
the kitchen should be connected with the sink trap at the inlet side
of the trap.

=Urinals.=--As a rule, no urinals should be tolerated within a house;
they are permissible only in factories and office buildings. The
material is enameled iron or porcelain. They must be provided with a
proper water supply to flush them.

=Overflows.=--To guard against overflow of washbasins, bath tubs,
etc., overflow pipes from the upper portion of the fixtures are
commonly provided. These pipes are connected with the inlet side of
the trap of the same fixture. They are, however, liable to become a
nuisance by being obstructed with dirt and not being constantly
flushed; whenever possible they should be dispensed with.

=Safes and Wastes.=--A common usage with plumbers in the past has
been to provide sinks, washbasins, bath tubs, and water-closets, not
only with overflow pipes, but also with so-called safes, which consist
of sheets of lead turned up several inches at the edge so as to catch
all drippings and overflow from fixtures; from these safes a drip pipe
or waste is conducted to the cellar, where it empties into a sink. Of
course, when such safe wastes are connected with the soil or waste
pipes, they become a source of danger, even if they are trapped, as
they are not properly cared for or flushed; and their traps are
usually not sealed. Even when discharging into a sink in the cellar,
safes and safe waste are very unsightly, dirty, liable to accumulate
filth, and are offensive. With open plumbing, and with the floors
under the fixtures of nonabsorbent material, they are useless.

=Water-closets.=--The most important plumbing fixtures within t