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4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 1 4.2.14 Making Repairs or Replacements on Propane Tubing Persons who repair or replace.

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Presentation on theme: "4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 1 4.2.14 Making Repairs or Replacements on Propane Tubing Persons who repair or replace."— Presentation transcript:

1 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 1 4.2.14 Making Repairs or Replacements on Propane Tubing Persons who repair or replace propane distribution tubing must take certain precautions to ensure the new joints are mechanically secure and free of leaks. Also, they must use procedures that minimize the hazards of working in a potentially gaseous atmosphere. In this module you will learn to identify: (1)Procedures basic to the repair or replacement of PE tubing (2)Procedures basic to the repair or replacement of corrugated stainless steel tubing (CSST) or copper tubing

2 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 1 Procedures for the Repair or Replacement of PE Tubing Remove sources of ignition Use non-sparking tools Control the amount of escaping propane vapor Care must be exercised when performing any propane leak repair, such as: Safety Considerations for Mechanical Joints PE pipe being joined mechanically must not be gouged or scratched. Transition connections should be made over firm ground whenever possible. If there is the possibility of excessive ground settlement, a split piece of rigid pipe which spans the settlement area should be installed under the connection.

3 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 2 Procedures for the Repair or Replacement of PE Tubing Critical Safety Practices Required During PE Distribution Line Repair Operations Persons making repairs on PE distribution lines in jurisdictional pipelines should be qualified for this task and preventing accidental ignition according the pipeline operator’s written Operator Qualification Plan. Persons making repairs on PE lines that have been in gas service must be aware of the hazard of accidental fire and explosion inherent in PE line repair operations, and apply appropriate grounding procedures, while using suitable personal protective equipment (PPE) and effective ignition prevention measures.

4 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 2 Procedures for the Repair or Replacement of PE Tubing Critical Safety Practices Required During PE Distribution Line Repair Operations 1.After PE distribution lines are placed into service, an electrical charge accumulates on both the inner and the outer surface of polyethylene piping as well as on any connected metal. 2.A static charge can bleed-off to a lower level by conduction through air, or by progressive induction, or conduction to nearby materials. A swift bleed-off, or a static discharge, may be evidenced by an arc or "jolt" when a person approaches within 6" or less of a charged surface. 3.Static electricity represents an ignition source: The danger occurs when the spark, if over 3,000 volts, generates enough heat to ignite the gas-in-air mixture.

5 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 3 Critical Safety Practices During PE Repair Operations Figure 1. Wrapping Polyethylene Pipe to Control Static Electricity Factors Affecting Grounding of Polyethylene Pipe— Control of static electricity to minimize it as an ignition source is provided by grounding the PE line. Grounding can be accomplished by establishing and maintaining a film of moisture on the pipe surface. After the surface of the exposed plastic pipe has been wetted down [with a mixture of dishwashing detergent & water], wet burlap or cotton (which has been dipped into a bucket of water-liquid dishwashing detergent solution) must also be draped around the plastic pipe starting at the point where the pipe enters the soil.

6 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 4 Preliminary Safety Precautions with Static Electricity Persons working with the pipe should wear flame resistant coveralls, flame resistant gloves, Nomex hoods, hard hats, and air-tight goggles. If available, fresh air breathing apparatus should be used when applicable. Position a manned fire extinguisher near the bell hole opening, taking into consideration the direction of blowing gas and wind direction. Periodically spray the entire exposed surface of the plastic pipe with a water and detergent solution. Ground a broken tracer wire by sticking the exposed ends into the ground away from the plastic pipe. Spray the locating tape or marking tape with a water and detergent solution and tuck the tape into the soil away from the pipe to help prevent contact with the pipe. From the top of the bell hole drape the exposed plastic pipe with burlap completely saturated with a water and detergent solution. Cover the pipe from the ground to the break or area to be cut.

7 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 5 Procedures for the Repair or Replacement of PE Tubing Be certain the wet burlap is in contact with the ground. Ungrounded wet burlap can create a higher static charge than dry plastic pipe, if accidentally discharged. If the pipe is cut with a saw or pipe scissors, ground the cutting tool using a No. 12 AWG standard copper wire brazed to the tool at one end and a ground rod at the other end. Drive the ground rod into the ground before using the cutting tool(s). Figure 2. Controlling Static Electricity When a Squeeze-off Tool is Used

8 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 5 Procedures for the Repair or Replacement of PE Tubing Figure 3. Four-Inch IPS Squeeze Tool with Static Electric Grounding Device Courtesy: Allied Corrosion Industries, Inc. Figure 4. Squeezing-Off Plastic Pipe Before starting repair operations, the flow of gas should be stopped by closing line valves upstream and downstream of the damaged or leaking pipe section, and if applicable, at the supply tank. If gas flow cannot be stopped by closing valves, the use of squeeze-off tools may be necessary.

9 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 7 Purging Plastic Pipe Figure 5. Purging Plastic Pipe of Propane Gas Propane passing through the open end of a polyethylene pipe generates static charges. Therefore, to control the static charge the end of the pipe is grounded the same as a pipe break or modification. Open two bell holes. Open one bell hole to expose the pipe end and one bell hole for the squeeze-off tool.

10 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 8 Repair or Replacement of CSST Figure 6. Damaged CSST If the tubing is damaged determine the severity of the damage and if necessary, the method of repair. Situation Where No Repair is Required. No repairs or replacement of the tubing is necessary if the tube is only slightly dented caused by impact or crushing, as illustrated in Figure 6. Note the damaged area of the tube has reduced the diameter of the tube less than 1/3.

11 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 8 Repair or Replacement of CSST Figure 7. Tubing Significantly Crushed or Dented Figure 8. Kink in CSST Caused by Bending Beyond Minimum Bend Radius Repair of Damage. CSST tubing must be replaced under the following conditions: Note the damaged area of the tube (Figure 7) has reduced the diameter of the tube more than 1/3 of its original diameter. Tubing has been bent beyond its minimum bend radius causing a crease or kink that remains, as illustrated in Figure 8.

12 4.2.14 Student Book © 2004 Propane Education & Research CouncilPage 9 Repair or Replacement of CSST Figure 9. Repair Using the Line Splice Method Method of Repair. A line splice can be made using two straight fittings and a steel coupling, as illustrated in Figure 9. However, if the tube run is short and easily accessible, the preferred repair method is to replace the entire length of the damaged tube.

13 4.2.14 Student Book © 2004 Propane Education & Research CouncilPages 10 - 12 Time to See If You Got the Key Points of This Module… Complete the Review on pages 10 & 11. See if you are ready for the Certification Exam by checking off the performance criteria on page 12.


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