that operate at a maximum pressure of 350 psi and in
This section will provide general information on the
water or gas lines that operate at a maximum pressure
piping and tubing that you will use to work on shipboard
of 400 psi.
piping systems. For details on any specific system, see
the ship piping plans (MIL-STD-777) and lists of
CARBON MOLYBDENUM (CMO) ALLOY
materials.
SEAMLESS STEEL TUBING is used in high-pressure
steam lines that work at pressures of 401 to 1200 psi
SEAMLESS STEEL PIPE is available in standard
and have an operating temperature of 875F. CMO
and extra strong wall thicknesses and comes in lengths
tubing is used extensively throughout ships' steam
of 12 to 22 feet. In the standard wall thickness, it is
systems, but as the piping systems wear out, CMO
available in sizes from l/8 inch to 16 inches IPS. Pipe
tubing is being replaced with seamless
sizes l/8 inch to 3/8 inch come with plain ends, while
chromium-molybdenum alloy steel tubing. It is usually
sizes l/2 inch to 16 inches come with beveled ends for
used in 600 psi systems. This tubing comes in lengths
welding. In the extra strong wall thickness, it is
of 12 to 24 feet.
available in sizes from 2 inches to 16 inches IPS. It may
or may not be galvanized. This pipe is ordinarily
stocked with plain ends only. Seamless steel pipe is
ALLOY STEEL TUBING is used in high-pressure
used aboard ship for diesel exhaust systems, overflow
steam lines that work at pressures of 1201 to 1500 psi
lines, sounding tubes, vents, and air intake systems.
and have an operating temperature of 1000F. This
tubing also comes in lengths of 12 to 24 feet.
WELDED STEEL PIPE, either galvanized or
ungalvanized (black), is also available in standard and
NONFERROUS TUBING is used for some
extra strong wall thicknesses. In the standard wall
shipboard piping systems and almost all shipboard heat
thickness, it is available in sizes l/8 inch to 12 inches
exchangers. Nonferrous materials are used primarily
IPS. The galvanized pipe comes in lengths of 16 to 22
feet, while the ungalvanized pipe comes in lengths of
are required. Typical shipboard applications of
12 to 22 feet. This pipe comes with beveled ends for
nonferrous tubing are described in the following
welding. The extra strong wall thickness pipe is
paragraphs.
available in sizes from l/4 inch to 12 inches IPS. It
Several types of SEAMLESS ALUMINUM
comes in lengths of 12 to 22 feet and is ordinarily
ALLOY TUBING are available. Tubing made of the
stocked with plain ends only. Welded steel pipe is used
aluminum alloy 6061 is used primarily for dry lines in
primarily for general service such as plumbing drain
magazine sprinkling systems. It is also used in some
lines aboard ship.
structural applications. Tubing made of the aluminum
STRUCTURAL STEEL TUBING is supplied in
alloy 5052 is used for bilge and sanitary drain systems.
lengths of 12 to 24 feet. This tubing is not intended for
SEAMLESS BRASS TUBING (semi-annealed
pressure applications. It is normally used on such
and light-annealed) is available in types and sizes
structural jobs as 20mm and 40mm gun mounts and
suitable for operating pressures that range from 200 psi
searchlight platforms. Structural tubing made by the
to 4000 psi. It is used in systems for either fresh water
seamless processes has a tensile strength of 60,000 psi.
or another fluid. However, it is not approved for any
The welded structural steel tubing has a tensile strength
seawater applications. The seamless hard-drawn brass
of 50,000 psi.
tubing is used for voice and pneumatic tube
SEAMLESS STEEL TUBING is used in oil, steam,
installations.
and waterline systems. This tubing is available in a
SEAMLESS COPPER TUBING is intended for
variety of types. The type used will depend upon the
general use aboard ship. If it is not joined by threaded
working pressure and temperature that is to be
fittings, you may use flanged joints, soldered joints, or
maintained in the lines.
flared fittings. Other types of copper tubing are
WELDED STEEL TUBING is available in two
available for various uses such as refrigeration
types. Their uses are as follows: Type A is used in
installations, plumbing and heating systems, gasoline
steam and oil lines where the maximum working
systems, lubrication systems, and other shipboard uses.
pressure is 150 psi. It is also used in water and gas lines
COPPER ALLOY TUBING is available in a
that operate at a maximum working pressure of 225 psi.
composition of either 70-30 or 90- 10. The first number
Type B is used in steam lines that operate at a maximum
working pressure of 300 psi. It is also used in oil lines
15-4