4.2.13

1. 4.2.13 Installing Buried Distribution Lines Using Polyethylene Pipe & Heat Fusion Persons who install polyethylene (PE) pipe and join it using heat fusion must be aware of the code requirements and material standards that apply to the operation. Installing personnel must be qualified to perform this task, and aware that more rigorous qualification requirements apply to installers who install PE or repair PE distribution lines in jurisdictional pipeline systems. • In this module you will learn to identify: • Characteristics and standards that apply to polyethylene pipe, tubing, and associated fittings • Qualifications/functions required of installing personnel • Appropriate responses to abnormal conditions • Procedures for joining polyethylene pipe with heat fusion • Safety practices and precautions used with PE pipe

2. Characteristics & Standards that Apply to PE Tubing, & Associated Fittings Polyethylene (PE) pipe and tubing is the only type of plastic listed for use for [buried distribution] gas piping in NFPA 58, LP-Gas Code.Polyethylene is what is known as a thermoplastic and may be joined either by heat fusion (welding) or by mechanical fittings. Polyamide (PA) tubing is approved for use in emergency shutdown systems for bulk plant and cargo tank tanks in the 2004 edition of NFPA 58.

3. Characteristics & Standards that Apply to PE Tubing, & Associated Fittings • PE tubing must be • Installed underground with a minimum burial depth of 18 inches below grade or other protection must be provided if the minimum 18 inch depth cannot be attained • Used in propane vapor service only and not subject to operating pressures in excess of 30 psig • Fully supported in the burial trench and protected from sharp objects and rock in the backfill material • Provided flexibility by “snaking” the tubing in the burial trench • Terminated by the use of an approved protective riser where PE emerges from the ground in the form of an anodeless riser or field-assembled service head adapter • Provided a buried insulated electrical wire or conductive locating and warning tape installed above the tubing for the purpose of tracing and locating the buried PE tubing

4. Figure 1. Sample Manufacturer’s Production Code Markings Characteristics & Standards that Apply to PE Tubing, & Associated Fittings NFPA 58, LP-Gas Code, 2001 edition requires that piping and tubing manufacturers meet identified specification requirements in the manufacturing and testing of those materials. Distribution system installers must ensure that the materials used in piping systems are designated by the manufacturer as conforming to the required standard(s).

5. Figure 1. Sample Manufacturer’s Production Code Markings Characteristics & Standards that Apply to PE Tubing, & Associated Fittings Polyethylene pipe [& tubing] must be marked in compliance with the product marking requirements of ASTM D2513, and must include the • Manufacturer’s name or trademark • Standard Dimensional Ratio (SDR) of the pipe • Size of the pipe (either copper tubing size—CST, or iron pipe size—IPS) • Designation polyethylene (PE) • Date manufactured • Designation ASTM D2513

6. Figure 1. Sample Manufacturer’s Production Code Markings Characteristics & Standards that Apply to PE Tubing, & Associated Fittings The required markings must appear at least every two feet of pipe or tubing length. All fittings used to join polyethylene pipe or polyethylene tubing shall be tested and recommended by the manufacturer for use with polyethylene (PE) pipe and shall be installed according to the manufacturer’s written procedure. Polyethylene pipe cannot be joined by a threaded or miter joint.

7. NFPA 58 NFPA 58 2001 2004 PE Installation Personnel Qualifications 1.5 Qualification of Personnel. Persons… whose primary duties fall within the scope of this code shall be trained in proper handling procedures. Refresher training shall be provided at least every three years. The training shall be documented. 4.4 PE tubing and pipe installed in jurisdictional pipeline systems must be installed by persons qualified to install PE materials, valves and fittings as required by 49 CFR Part 192. In some cases, such as repair of existing PE piping, personnel qualifications must be documented in compliance with the pipeline operator’s written Operator Qualification Plan.Persons working on jurisdictional pipelines, and pipeline operating companies must comply with requirements of 49 CFR 192.285 and 287 that apply where NFPA 58 is silent or any that exceed the requirements of NFPA 58.

8. PE Installation Personnel Qualifications Inspecting PE Pipe— When shipments of pipe are delivered they should be inspected to ensure a quality product is received. PE pipe must be carefully inspected for cuts, gouges, deep scratches, and other defects before use. During shipment the entire load of pipe should be covered to protect it from diesel exhaust. When the cover is removed, examine the pipe for diesel fuel contamination. The segment of pipe containing defects shall be cut out. The only exception is that pipe with scratches and gouges with a depth less than 10% of the wall thickness can be used. Storing PE Pipe—PE pipe and tubing should be stored to minimize the material being damaged by crushing, piercing, or extended exposure to direct sunlight.

9. Figure 2. Cutting Polyethylene Pipe PE Installation Personnel Required Functions Handling PE Pipe

10. PE Installation Personnel Required Functions • Trenching and Backfilling— • PE pipe or tubing shall be laid and continuously supported on undisturbed or well‑compacted soil. Do not use blocks or allow pipe to rest on rocks or large clods of dirt, because this will set up shearing stresses in the pipe, or may cut or puncture it during backfilling. • In rock excavation, pad the ditch line with at least six (6) inches of clean fill material such as sand. • Allow for contraction by "snaking" the pipe from one side of the ditch to the other. • Prior to beginning backfilling, the entire trench is to be examined to make sure the PE pipe is continuously supported at all points on undisturbed or well‑compacted soil.

11. Figure 3. Critical Stress Area PE Installation Personnel Required Functions Trenching and Backfilling—The area of the service line extending out from the point where it is connected to the main is a critical stress area. The backfill in this area should be compacted around and under tie‑ins. Also, a protective bridging sleeve should support the service line in this critical area.

12. Figure 4. Trench Construction and Terminology PE Installation Personnel Required Functions Placing Pipe in Trenches—PE piping may be joined in the trench or above grade, although most joining is done above grade prior to lowering pipe into the trench. When heat fusion is used, sufficient time must be allowed for the joint to set‑up before moving the pipe. Allow [heat] fusion joints to cool at least 10 minutes before stressing pipe either by lowering into ditch or pressure testing.

13. Figure 5. Installing Tracer Wire PE Installation Personnel Required Functions Installing Tracer Wire— A metallic wire called a "tracer wire" or electrically conductive warning tape is placed in the trench with the pipe during the backfilling operation. It is inserted after the pipe is installed and half-way through the backfilling process. The tracer wire is used as a conductor of the electrical signal when an underground pipe locator is used to locate the polyethylene pipe. Tracer wire should be placed in the trench above and separated from the PE pipe by approximately 6 inches of soil before the trench is completely back filled with soil.

14. Appropriate Responses to Abnormal Operating Conditions Damaged Pipes and/or Fittings— Each imperfection or damaged pipe or fitting that would impair the serviceability of PE pipe must be repaired by a patching saddle, or removed and/or replaced. Leaking Pipe and/or Fittings— When a leak is found it should be promptly scheduled for repair according to company procedures. Exposed Piping— PE piping that has been exposed or deformed must be appropriately supported and covered.

15. Figure 6. Typical Butt Fusion Joint Figure 7. Heater Used for Butt Fusion Procedures for Joining Polyethylene Pipe with Heat Fusion The principle of heat fusion is to heat two surfaces to a designated temperature, then fuse them together by applying a sufficient force. It is essential to follow the pipe manufacturer’s procedures when making a heat fusion joint.

16. Figure 8. Butt Fusion Machine for Small Diameter Pipe Procedures for Joining Polyethylene Pipe with Heat Fusion Butt Fusion Figure 9. Facing Tool & Facing Procedure

17. Procedures for Joining Polyethylene Pipe with Heat Fusion Butt Fusion Figure 10. Aligning Pipe Ends Figure 11. Heating Pipe Ends to be Joined

18. Procedures for Joining Polyethylene Pipe with Heat Fusion Butt Fusion Figure 12. Manufacturer’s Specifications for Heating Temperatures and Time Cycles

19. Procedures for Joining Polyethylene Pipe with Heat Fusion Figure 13. Well Formed Bead (Roll-Back)

20. Procedures for Joining Polyethylene Pipe with Heat Fusion Figure 14. Bead Sizes

21. Procedures for Joining Polyethylene Pipe with Heat Fusion • Inspect the fusion joint for a uniform melt pattern around the circumference of the pipe. • Ensure the bead size is in the range specified by the pipe manufacturer. • Ensure the ends of the pipe section are within the acceptable range of alignment (15 mils for 2” pipe).

22. Figure 15. Butt Fusion Joint Procedures for Joining Polyethylene Pipe with Heat Fusion • A characteristic of an acceptable butt fusion joint is indicated by a two-bead roll-back encircling properly aligned pipe. Visual indication of an inadequate butt fusion joint includes the following: • Melted bead formed only on one side • Ends of the pipe are not aligned • Displaced melt bead • Melt bead not fully formed

23. Figure 16. Standard Socket Fusion Joint Procedures for Joining Polyethylene Pipe with Heat Fusion Socket Fusion

24. Figure 17. Squaring & Cleaning the Pipe Figure 18. Ensuring Proper Insertion Depth With Cold Ring Clamp and Chamfering the Pipe End Procedures for Joining Polyethylene Pipe with Heat Fusion

25. Procedures for Joining Polyethylene Pipe with Heat Fusion Figure 19. Inserting Pipe and Fitting on the Heater Faces

26. Procedures for Joining Polyethylene Pipe with Heat Fusion Figure 20. Socket Fusion Time Cycles

27. Procedures for Joining Polyethylene Pipe with Heat Fusion Figure 21. Joining Socket to Pipe End

28. Procedures for Joining Polyethylene Pipe with Heat Fusion Figure 22. Allowing the Joint to Cool Figure 23. Socket Fusion Joint

29. Procedures for Joining Polyethylene Pipe with Heat Fusion Visual indication of an inadequate socket fusion joint may show: • Incomplete melt pattern • Excessive melt • Pipe is inserted to fuse into the socket leaving a gap • Pipe is not inserted into the socket far enough—this is sometimes caused by not using a depth ring and cold clamp Figure 23. Proper Socket Fusion Joint

30. Procedures for Joining Polyethylene Pipe with Heat Fusion Saddle Fusion This technique consists of simultaneously heating both the external surface of the pipe and the matching surface of the “saddle” type fitting until both surfaces reach fusion temperature. The melted pattern is inspected and the fitting is placed on the heated section of the pipe, held in place under pressure for the prescribed time and allowed to cool. Figure 24. Typical Saddle Fusion Joint Saddle fusion is used to join saddle fittings and tapping tees to main lines and requires a special application unit for joining.

31. Procedures for Joining Polyethylene Pipe with Heat Fusion Figure 25. Roughening the Pipe

32. Procedures for Joining Polyethylene Pipe with Heat Fusion Figure 26. Positioning Heating Tool Between the Pipe (Main) and Fitting

33. Procedures for Joining Polyethylene Pipe with Heat Fusion Figure 27. Saddle Fusion Time Cycle Guidelines for 2406

34. Procedures for Joining Polyethylene Pipe with Heat Fusion • Remove the fitting from the heating tool and the heating tool from the main, insuring no melt has stuck the heater faces. Make sure the heater face corners do not dig into the pipe wall. • Check to ensure the melt pattern on the main and fitting are complete. • Press the fitting on the main very quickly with firm pressure until a final bead is developed around the entire base of the fitting. • Lock the jig into the hold and cooling position. Figure 28. Bead Width Guidelines for 2406

35. Procedures for Joining Polyethylene Pipe with Heat Fusion Check to ensure that melt has been squeezed out completely around the base of the saddle. ·Check to ensure the saddle fitting is entirely within the pipe melt pattern. Evaluate the particular areas indicated in Figure 29 Figure 29. Saddle Fusion Joint

36. Procedures for Joining Polyethylene Pipe with Heat Fusion Visual indicators of an inadequate saddle fusion include the following: • Incomplete melt pattern • Melt pattern appears only on the edges • Excessive melt pattern • Voids in the melt pattern • Saddle fitting excessively pushed into the main pipe body or misaligned with the main pipe Figure 29. Saddle Fusion Joint

37. Critical Safety Practices During PE 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.

38. Critical Safety Practices During PE Repair Operations • 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. • 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. • 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.

39. Critical Safety Practices During PE Repair Operations 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. Figure 30. Wrapping Polyethylene Pipe to Control Static Electricity

40. 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.

41. Controlling Static Electricity During Repair Operations 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 31. Controlling Static Electricity When a Squeeze-off Tool is Used

42. Stopping the Flow of Propane with Squeeze-Off Tools 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. Courtesy: Allied Corrosion Industries, Inc. Figure 33. Squeezing-Off Plastic Pipe Figure 32. Four-Inch IPS Squeeze Tool with Static Electric Grounding Device

43. Courtesy: Allied Corrosion Industries, Inc. Figure 32. Four-Inch IPS Squeeze Tool with Static Electric Grounding Device Stopping the Flow of Propane with Squeeze-Off Tools The use of squeeze-off tools to stop the flow of propane in a polyethylene pipe creates turbulence within the carrier pipe and increases the velocity of the propane flow at the point of squeeze-off. Both the increased turbulence and increased velocity of propane flow significantly increases the accumulation of static charges on the pipe surfaces. Electrically ground the squeeze-off tools before approaching or contacting the pipe. Open three bell holes, one for the pipe work area and two for the squeeze-off tools, as illustrated in Figure 31.

44. Purging Plastic Pipe 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. Figure 34. Purging Plastic Pipe of Propane Gas

45. Time to See If You Got the Key Points of This Module… • Complete the Review on pages 32 - 34. • See if you are ready for the Certification Exam by checking off the performance criteria on pages 35 - 37.