4.2.16
Installing Copper Tubing in
Distribution Systems
Personnel who install copper tubing are required to know
the proper techniques for cutting, bending, joining and
protecting copper tubing, as well as the appropriate code
requirements.
In this module you will learn to identify:
(1) Characteristics and specifications of copper tubing used in
propane vapor distribution systems
(2) Common practices used in working with tubing
(3) Guidelines for installing copper tubing
4.2.16 Student Book  © 2004 Propane Education & Research Council
Page 1
Characteristics & Specifications of Copper Tubing
Approved for Propane
Seamless Copper Water Tubing— Copper water tubing types K and L are
designated by ASTM standard sizes, with the actual outside diameter
always 1/8 inch larger than the nominal size. Each type consists of a series of
sizes with different wall thickness (Figure1). Copper tubing is ordered by its
nominal size.
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Characteristics & Specifications of Copper Tubing
Approved for Propane
Figure 1. Dimensions of Nominal Size Copper Tubing (ASTM-B88)
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Characteristics & Specifications of Copper Tubing
Approved for Propane
Soft Copper Tubing—Since soft copper tubing is flexible and easily bent,
proper installation requires it to be supported by clamps and suitable brackets.
Soft copper tubing is most often connected using flared and brazed fittings.
Solder used for brazing copper propane lines must have a minimum melt
temperature of 1,000° F.
Soft solder should be used only on water lines and is not permitted for use on
gas lines.
Air Conditioning and Refrigeration (ACR ASTM B-280) Tubing— ACR
tubing is usually charged with nitrogen gas to keep it clean and dry until it is
used. When used for propane distribution, it should have the ends plugged
immediately after cutting a length from a piece of stock tubing.
ACR tubing is sized by the actual outside diameter (OD) of the tube.
4.2.16 Student Book  © 2004 Propane Education & Research Council
Pages 2 & 3
Characteristics & Specifications of Copper Tubing
Approved for Propane
Figure 2. Common Flare Fittings
4.2.16 Student Book  © 2004 Propane Education & Research Council
Page 3
Common Practices Used in Working with Tubing
Unrolling Short lengths of tubing are straightened by
repeated rolling of the tubing on a flat surface while
pressing down on the tubing with the palms of your
hands. Longer sections of tubing are straightened by
carefully bending the tubing with your hands.
Cutting After the cut is made, remove any metal chips
on the outside of the tubing with a file. Also, remove the
burrs on the inside of the tubing with a reamer and make
a bevel on the leading edge of the flare.
Figure 4. Tubing Cutter
Bending. Although soft tubing can be bent by hand, a tube bending tool should be
used to protect the tubing from kinks and flat spots during bending. Two types of
tubing benders are the spring-type bender and the lever-type bender.
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Common Practices Used in Working with Tubing
Flaring and Connecting Flared Tubing. In
order to flare the end of a piece of soft copper tubing,
a special flaring tool called a die block is used to
form the flare.
Step 1:
Select the appropriate flare nut.
Step 2:
Place the flare nut on the tubing before
putting the tubing in the die block.
Figure 5. Die Block
Flaring Tool
Figure 6. Flared Tubing Connection and Assembly
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Common Practices Used in Working with Tubing
Step 3:
Flare the end of tubing according to the
operating instructions for the flaring tool.
The following examples illustrate
incorrect and correct flaring:
Figure 9. Correctly
Formed Tubing Flare
Figure 7. Incorrectly
Formed Tubing Flare–
Too Small
Figure 8. Incorrectly
Formed Tubing Flare–
Too Large
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Common Practices Used in Working with Tubing
Step 4:
Clean the flare nut threads on the flared end of the tubing
and the threads on the flare fitting before assembling the
flared tubing connection.
Step 5:
Tighten the flare nut onto the flare fitting by hand first before
using a wrench.
Step 6:
Once the flare tubing connection is hand tight, use two
wrenches—one to hold the flare fitting and one to tighten
the flare nut onto the flare fitting.
Do not over-tighten. Over-tightening can produce a crack in
the metal of the flare nut, leading to a split and loss of the gastight seal.
Do not use pipe thread sealing compounds on the seats of
brass flare fittings. Flared copper connections are metal-tometal seals that may not seat and seal properly if thread
sealing compounds are used.
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Common Practices Used in Working with Tubing
Connecting Copper Tubing by Brazing. Silver brazing is another method
to connect copper tubing. When silver brazing, follow these steps:
Step 1:
Measure, mark and cut the tubing to the
required length.
Step 2:
Use the reaming tool on the tube cutter to
remove the burr from the inside of the tube.
Figure 10.
Figure 11.
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Common Practices Used in Working with Tubing
Step 3:
Clean the inside of each fitting by scouring
with a fitting brush. Apply a thin layer of flux
to the surfaces to be joined, then slide the
tubing ends and fittings together.
Step 4:
Apply a thin layer of flux to the silver alloy
brazing rod. Hold the tip of the torch flame
against the fitting until the flux begins to
sizzle, then move the flame around to the
other side of the fitting to ensure even heat.
(When the flux begins to bubble, the
connection should be hot enough for
brazing.)
Figure 12.
Figure 13.
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Common Practices Used in Working with Tubing
Step 5:
Touch the end of the brazing filler to the
pipe just below the fitting. If it melts and is
drawn into the joint, the pipe is sufficiently
hot.
Step 6:
Quickly apply the brazing filler along both
seams of the fitting, allowing it to be drawn
into the fitting by capillary action. When
correctly brazed, the joint will show a thin
bead of silver-colored brazing around each
seam.
Figure 14.
Figure 15.
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Common Practices Used in Working with Tubing
Step 7:
Allow the joint to cool until the brazing material has a
frosty appearance rather than a shiny silver color one.
Then, wipe away any excess material with warm water, a
wet cloth, and a brush. (Brazing filler will harden in a
minute or less if the joint has not been overheated.)
Figure 16.
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Guidelines for Installing Copper Tubing
Buried Distribution Lines— Where copper tubing is used in an underground
tank installation, a dielectric union should be installed at the building service
entrance to electrically isolate the copper tubing from steel pipe or tubing used in
the building distribution lines. Non-conductive insulating material should also be
installed to prevent contact between the copper tubing and the steel of the
underground tank, dome, and riser.
Buried copper tubing should be one continuous piece. Buried brass fitting joints
should be avoided.
Distribution Lines Inside Homes and Businesses
•
In accordance with NFPA 54, 2002, 6.3.2, flared connections are not permitted
in concealed spaces, while brazed connections are permitted.
•
Unprotected copper tubing should not be used in wall partitions or other
locations that potentially subject it to puncture by nails, screws or other
fasteners. If copper is located where it is subject to potential puncture or other
damage, it must be a single unsecured run and protected by a minimum 0.0508
inch thick steel pipe casing or suitable metal plate strike barrier.
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Guidelines for Installing Copper Tubing
Distribution Lines Inside Homes and Businesses
•
Copper tubing cannot be continually bent back and forth without eventual
breakage. For this reason, it must not be used to connect appliances subject to
being moved for cleaning or other purposes by the customer. The bending
action and stress on the tubing is especially severe at the points where the
connections are made.
•
Installers must exercise care when flaring copper tubing. If a flare is made that
contains splits or other imperfections, or is too large or too small for the flare
nut, it must be cut off, and a proper flare made. Because flared copper tubing
joints are metal-to-metal formed seals, do not use pipe thread sealing
compounds. Also, know how to properly tighten brass fittings to assure gastight joints in copper lines without splitting the tubing or flare nut.
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Guidelines for Installing Copper Tubing
Distribution Lines Inside Homes and Businesses
NFPA 54
2002
5.6.5 Workmanship and Defects. Gas pipe, tubing, and fittings shall
be clear and free from cutting burrs and defects in structure or
threading and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe, tubing, and fittings shall not be repaired. Defective
pipe, tubing, and fittings shall be replaced.
7.1.1.1 Prior to acceptance and initial operation, all piping installations shall be
inspected and pressure tested to determine that the materials, design, fabrication,
and installation practices comply with the requirements of this code.
7.1.1.3 Where repairs or additions are made following the pressure test, the
affected piping shall be tested. Minor repairs and additions are not required to be
pressure tested provided that the work is inspected and connections are tested
with a non-corrosive leak-detecting fluid or other leak-detecting methods approved
by the authority having jurisdiction.
7.1.1.4 Where new branches are installed from the point of delivery to new
appliance(s), only the newly installed branch(es) shall be required to be pressure
tested. Connections between the new piping and the existing piping shall be tested
with a non-corrosive leak-detecting fluid or approved leak-detecting methods.
4.2.16 Student Book  © 2004 Propane Education & Research Council
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Guidelines for Installing Copper Tubing
8.5.7 Sediment Trap. If there is no sediment trap, one shall be installed as
close to the inlet of the equipment as practicable at the time of equipment
installation. The sediment trap shall be either a tee fitting with a capped nipple in
the bottom outlet as illustrated in Figure 8.5.7, or another device recognized as
an effective sediment trap. Illuminating appliances, ranges, clothes dryers,
decorative appliances for installation in vented fireplaces, gas fireplaces, and
outdoor grills shall not be required to be so equipped.
Gas supply inlet
To
equipment
inlet
Pipe tee
Figure 17. Sediment Trap
(as shown in Figure 8.5.7 in NFPA 54, 2002 edition)
Pipe nipple
3 inches
minimum
4.2.16 Student Book  © 2004 Propane Education & Research Council
Cap
Page 12
Time to See If You Got the Key Points of
This Module…
• Complete the Review on pages 13 & 14.
• See if you are ready for the Certification
Exam by checking off the
performance criteria on pages 15 &
16.
4.2.16 Student Book  © 2004 Propane Education & Research Council
Pages 13 - 16