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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:
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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: • Characteristics and specifications of copper tubing used in propane vapor distribution systems • Common practices used in working with tubing • Guidelines for installing copper tubing
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.
Characteristics & Specifications of Copper Tubing Approved for Propane Figure 1. Dimensions of Nominal Size Copper Tubing (ASTM-B88)
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.
Characteristics & Specifications of Copper Tubing Approved for Propane Figure 2. Common Flare Fittings
Common Practices Used in Working with Tubing UnrollingShort 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. CuttingAfter 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.
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. Figure 5. Die Block Flaring Tool Figure 6. Flared Tubing Connection and Assembly
Figure 7. Incorrectly Formed Tubing Flare– Too Small Figure 8. Incorrectly Formed Tubing Flare– Too Large Figure 9. Correctly Formed Tubing Flare Common Practices Used in Working with Tubing
Common Practices Used in Working with Tubing 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 gas-tight seal. Do not use pipe thread sealing compounds on the seats of brass flare fittings. Flared copper connections are metal-to-metal seals that may not seat and seal properly if thread sealing compounds are used.
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: Figure 10. Figure 11.
Common Practices Used in Working with Tubing Figure 12. Figure 13.
Common Practices Used in Working with Tubing Figure 14. Figure 15.
Common Practices Used in Working with Tubing Figure 16.
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.
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 gas-tight joints in copper lines without splitting the tubing or flare nut.
NFPA 54 2002 Guidelines for Installing Copper Tubing Distribution Lines Inside Homes and Businesses 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.
Figure 17. Sediment Trap (as shown in Figure 8.5.7 in NFPA 54, 2002 edition) 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.
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.