Proper care in setting and looking after smoke pipes connecting with
chimneys would greatly lessen the number of fires chargeable to defective
construction.
In fitting the smoke pipe no opening should be left around it, and the
pipe should not project into the flue lining. (See fig. 8.) The joint
should be made air-tight by a closely fitting collar and boiler putty or
fireproof cement. The proper construction is shown in figure 8-B, but
if the pipe extends into the flue a shelf is formed on which soot will
accumulate, the flue area will be reduced and a poor draft may result.
Smoke pipes should enter the chimney horizontally, and the connection
through the chimney wall to the flue should be made with fire clay or
metal thimbles securely and tightly set in the masonry. If the walls are
furred, no wood should be within 12 inches of thimbles or any part of
the smoke pipe. The space between the thimble and wood furring should be
covered with metal lath and plaster.
[Illustration: Fig. 9.--Smoke pipe passing through a partition. A,
7/8-inch sides of partition; B, 2 by 4 studs in partition; C, ventilating
holes in the double galvanized iron ventilating thimble D. Thimble should
be at least 12 inches larger than pipe S.]
Flue holes when not in use should be closed with tight fitting metal
covers. If the room is papered the metal covers may also be papered,
provided there is no other smoke connection with the flue, or provided
a protective coating of asbestos paper is first applied over the metal.
If there is another connection the metal may become hot enough to scorch
the unprotected wall paper or set it afire. No smoke pipe should be
permitted within 18 inches of any woodwork unless at least that half of
the pipe nearest the woodwork is protected properly by 1 inch or more of
fireproof covering. A metal casing 2 inches from the upper half of the
pipe is sometimes employed to protect woodwork directly above it. When a
smoke pipe is so protected it should never be less than 9 inches from any
woodwork or combustible material. The storage of wooden boxes, barrels,
or any combustible should not be permitted under or near a furnace smoke
Pipe.
If a smoke pipe must be carried through a wood partition the woodwork
should be properly protected. This can be done by cutting an opening in
the partition and inserting a galvanized iron double-walled ventilating
thimble at least 12 inches larger than the smoke pipe (see fig. 9), or
protection may be afforded by at least 4 inches of brickwork or other
incombustible material. Smoke pipes should not pass through floors,
closets, or concealed spaces. They should not enter a chimney in a
garret. They should be cleaned at least once a year.