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HVACR216 - Hydronics
Fittings and Pipe Support
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Copper tubing
• Copper tubing was developed in the 1920s
to provide an alternative to iron piping in a
variety of uses.
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Desirable features
• Good pressure and temperature rating for
typical hydronic applications.
• Good resistance to corrosion from waterbased system fluids.
• Smooth inner walls that offer low flow
resistance
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Desirable features
• Lighter than steel or iron piping of
equivalent size.
• Ability to be joined by the well-known
technique of soft soldering
Copper pipe size
• Copper pipe is available in a wide range of
sizes and wall thicknesses.
• The type of tubing used in hydronic heating
is known as water tube.
• In the United States, copper water tube is
manufactured according to strict standards.
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ASTM B88
• This standard is known as ASTM B88.
• American Society for Testing and
Materials
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ASTM B88
• According to ASTMB88, the copper water
pipe size refers to the nominal inside
diameter of the pipe.
• The word “nominal” means that the
measured inside diameter is
approximately equal to the stated pipe size.
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Copper tube sizing
• The outside diameter of copper water tubing is
always 1/8” inch larger than the nominal inside
diameter.
• For example, the outside diameter (O.D.) of ¾”
inch type M copper tubing is .875 inches
• This is exactly 7/8” inches, or 1/8” inch larger
than the nominal pipe size.
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Copper tubing wall thickness
• Copper water tube is available in three wall
thicknesses designated as type K, L, and M in
order of decreasing wall thicknesses.
• The outside diameter of K, L and M tubing are
identical.
• This allows all three types of tubing to be
compatible with the same fittings and valves.
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Copper tubing
• The three types of copper tubing are easily
identified by color code printing along the tube.
• Type M copper tube = Red
• Type L copper tube = Blue
• Type K copper tube = Green
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Copper M tubing
• Because operating pressures of residential
and light commercial hydronic heating
systems are relatively low, the thinnest wall
copper tube (type M) is most often used.
• This wall thickness provides several times
the pressure rating of other common
hydronic system components.
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Hard Drawn Tubing
• Two common hardness grades of copper water
tube are available.
• Hard drawn tubing is supplied in straight, rigid
lengths of 10 and 20 feet.
• Because of its straightness and strength, hard
drawn tubing is the most commonly used type
of copper tubing in hydronic systems.
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Hard drawn copper Tubing
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Soft Copper Tubing
• So-called soft drawn tubing is annealed
during manufacturing to allow it to be
formed with simple bending tools.
• It is useful in situations where awkward
angles do not allow proper tubing
alignment with standard fittings.
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Annealing
• In the cases of copper this process is performed
by substantially heating the material (generally
until glowing) for a while and allowing it to cool.
• Unlike ferrous metals which must be cooled
slowly to anneal, copper can be cooled slowly in
air or quickly by quenching in water.
• In this fashion the metal is softened and prepared
for further work such as shaping, stamping, or
forming.
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Annealed copper tubing
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Hard drawn copper tubing support
• Horizontal runs of copper hard drawn tubing
must be supported at a maximum of every 12’.
• Vertical runs of copper hard drawn tubing must
be supported at a maximum of every 10’.
• Always refer to local code for proper
spacing
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Hard drawn copper tubing support
• These support spacings do not include any
allowances for the extra weight of other system
components such as circulators or expansion
tanks.
• When such components are present, the piping
should be supported immediately adjacent to the
component.
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Soft drawn copper tubing support
• Copper soft drawn tubing 1 ¼” and smaller on a
horizontal run must be supported at a maximum of
every 6’.
• Copper soft drawn tubing 1 ½”” and larger on a
horizontal run must be supported at a maximum of
every 10’.
• Vertical spacing for all sizes is 10’
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Pipe support materials
• A number of different types and styles of
supports are available for copper tubing.
Split rings
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Adjustable strap
2 hole pipe strap
J hook
Bell hanger
Clevis hanger
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Pipe insulator
Two hole plastic strap
Strut cushion clamp
Copper strap
Vertical pipe support
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Common pipe fittings
• Many of the pipe fittings used in hydronic
systems are the same as used in
conventional water supply systems.
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Couplings: (standard and reducing)
Standard
Reducer coupling
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Elbows: 90 degree and 45 degree
90 degree
45 degree
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Street elbows: (90 and 45 degrees)
Street 90
Street 45
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Tees: (Standard and reducing)
Standard
Reducing Tee
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Threaded adapters: (Male and female)
Male adapter
Female adapter
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Unions
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Ball valves
Sweat ball valve
NPT ball valve
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Gate valve
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Boiler drain valve
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Boiler Drain T
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Baseboard Tee