Figure 4-24.Types of pipe insulation.
Sponge felt paper can be purchased in blocks of
straight and preformed shapes for valves and fittings.
Cork pipe covering is a granulated material
processed from the bark of cork trees. Granulated cork
is compressed and molded to size and shape and
finished with a coating of plastic asphalt. Cork pipe
covering, as shown in view B, figure 4-24, is an ideal
covering for brine, ammonia, ice water, and all kinds
of cold waterlines, and it insulates well over a wide
low-temperature range. Cork pipe covering does not
rot or support combustion. Clean, sanitary, and odor
free, it is available in a wide variety of sizes and shapes
to fit various sizes of pipes and fittings.
Wool felt is made of matted fibers of wool, wool
and fur, or hair, worked into a compacted material by
pressure rolling. It is used on cold-water service and
hot-water return lines. Wool felt preformed pipe
covering is manufactured in thicknesses of l/2 to 1
inch, with a canvas jacket, as shown in view C, figure
4-24. It is manufactured in 3-foot lengths for straight
runs of pipe.
Flex rubber insulation, shown in view D, figure
4-24, is a tough, flexible rubber material constructed
of millions of uniform closed cells. It has
good-insulating qualities, good-cementing qualities,
excellent weather-aging qualities, and it is ideal for the
prevention of sweating cold-water lines. In addition,
it is water and flame resistant. Flex rubber insulation
is recommended for covering tubing used in
refrigeration and cold-water lines in homes, as well as
in industrial plants and commercial buildings. This
rubber insulating material comes in random lengths,
with a wall thickness size of 3/8 to 3/4 inch. It is made
to fit pipe sizes up to 4 inches.
Flex rubber insulation can be installed on pipes
and tubing by slipping the insulation over the pipe
when it is being assembled or by slitting the rubber
lengthwise and sealing it with cement. Before
installing flex rubber insulation on iron or galvanized
pipes, paint the pipes with an asphaltic base primer to
prevent corrosion caused by condensation.
Fiber glass pipe insulation, shown in view E,
figure 4-24, is composed of very fine glass fibers,
bound and formed together by an inactive resin type
of mixture. It is formed into a flexible hollow cylinder
and slit along its length for applying to pipes or tubing.
It is furnished in 3-foot lengths with or without jackets.
The insulation comes in thicknesses from l/2 to 2
inches and fits pipes from l/2 to 30 inches. Fiber glass
insulation has a long life; it will not shrink, swell, rot,
or burn. It is easily applied, light in weight, saves
space, and has excellent insulating qualities.
Antisweat insulation, shown in view F, figure
4-24, is designed for cold-water pipes. It keeps the
water colder in the pipes than most types of insulation;
and when installed properly, it prevents condensation,
or sweating, of the pipes.
The outstanding feature of antisweat insulation is
its construction. It is composed of an inner layer of
asphalt-saturated asbestos paper, a 1/2-inch layer of
wool felt, two layers of asphalt-saturated asbestos felt,
another l/2-inch layer of pure wool felt, and an outer
layer of deadening felts with asphalt-saturated felts.
The outer layer has a flap about 3 inches long that
extends beyond the joint to help make a perfect seal.
A canvas jacket is placed around each 3-foot length to
protect the outer felt covering.
Frostproof insulation, shown in view G, figure
4-24, is manufactured for use on (1) cold-water service
lines that pass through unheated areas and (2) those
lines exposed to outside weather conditions.