1 / 42

4.1.8

4.1.8. Selecting Piping and Tubing. After completing the gas customer profile and examining construction drawings, you are ready to apply code requirements and equipment sizing methods to produce the system layout and materials specifications. In this module you will learn to identify:

vasilis
Download Presentation

4.1.8

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 4.1.8 Selecting Piping and Tubing After completing the gas customer profile and examining construction drawings, you are ready to apply code requirements and equipment sizing methods to produce the system layout and materials specifications. • In this module you will learn to identify: • NFPA code requirements for vapor distribution systems • Characteristics and applications for piping and tubing materials • Sizing methods for buried distribution lines • Sizing methods for distribution lines on half-pound systems • Distribution lines requirements for 2-pound systems

  2. NFPA 58 2004 NFPA 54 2002 NFPA Code Requirements for Vapor Distribution Systems Two primary codes are used in designing propane distribution systems: • NFPA 58, LP-Gas Code, covering the propane supply container(s), the first and second-stage regulators, and the connecting distribution lines between the regulators • NFPA 54, National Fuel Gas Code, covering gas piping systems from the outlet of the second-stage or 2-PSI service regulator, into the building, and to installed gas appliances

  3. NFPA Code Requirements for Vapor Distribution Systems Figure 1. The Dividing Line for Applying NFPA 58 and NFPA 54

  4. NFPA 58 NFPA 58 2001 2004 NFPA Code Requirements for Vapor Distribution Systems NFPA 58 requirements for piping and tubing are found:

  5. NFPA 54 2002 NFPA Code Requirements for Vapor Distribution Systems NFPA 54 requirements for piping and tubing are found: Materials and installation requirements for building piping system components are found in Chapter 5: Gas Piping System Design, Materials, and Components Chapter 6: Gas Piping Installation.

  6. Characteristics of Piping and Tubing Materials Steel Pipeis durable, widely available, and very economical for use inside homes and businesses.Steel pipe is not a proper choice for piping runs in concealed spaces that require joining methods that are not accessible in the event of a leak or required piping modification. Figure 2. Steel Pipe

  7. Characteristics of Piping and Tubing Materials Copper Tubing Copper tubing is a highly flexible material often used as the buried distribution line. In small vapor distribution systems, copper tubing is economical and relatively simple to install. 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. Installers must exercise care when flaring copper tubing. If a flare is made that contains splits or other imperfections, 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, personnel must know not to use pipe thread sealing compounds and how to properly tighten brass fittings to assure gas-tight joints in copper lines without splitting the tubing or flare nut.

  8. Characteristics of Piping and Tubing Materials Polyethylene (PE) Tubing is increasingly used for buried distribution lines, especially with underground tank installations. It does not contribute to galvanic corrosion of underground tanks. Figure 3. PE Tubing & Mechanical Fitting of Anodeless Riser

  9. Characteristics of Piping and Tubing Materials Polyethylene (PE) Tubing— Service Limitations 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 • 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

  10. Characteristics of Piping and Tubing Materials Polyethylene (PE) Tubing— Special Considerations Persons who install PE tubing and fittings should be qualified by the manufacturer, supplier, or qualified trainers, and be thoroughly familiar with manufacturer written joining and installation procedures. Persons who make repairs of PE distribution lines that have been in service must be familiar with the ignition source hazard that PE pipe and tubing create due to static electricity, and should know and apply proper excavating and grounding methods to apply before and during repair operations. They should also use appropriate personal protective equipment, ignition prevention, and fire control measures throughout PE distribution repair operations.

  11. Characteristics of Piping and Tubing Materials Figure 4. Buried Polyethylene Tubing and Associated Fittings

  12. Characteristics of Piping and Tubing Materials Corrugated Stainless Steel Tubing (CSST) is widely used in new construction and modifications to existing vapor distribution systems. CSST is typically used in 2-PSI systems, but if properly sized, may be used for relatively short runs in half-pound systems. Figure 5. CSST and Fittings

  13. Characteristics of Piping and Tubing Materials Corrugated Stainless Steel Tubing (CSST)— Special Considerations: CSST can be used in 2-PSI systems or half-pound systems. Installers should be qualified by CSST manufacturers, suppliers, or qualified trainers and thoroughly familiar with the manufacturer’s installation procedures and instructions. Special carbon steel protective devices or plates are required to protect CSST where it is concealed, constrained from moving, or routed to areas within 3 inches of locations subject to puncture strikes.

  14. Characteristics of Piping and Tubing Materials Figure 6. In-Wall Sleeve Seal Figure 7. In-Slab Installation of CSST for an Island Appliance

  15. Sizing Methods for Buried Distribution Lines The term “pipe sizing” means the selection of the diameter of pipe or tubing which must be used. When sizing buried distribution lines select the diameter of pipe (or tubing) needed to deliver an hourly Btu load of gas for a specific distance with a loss of pressure of not more than 0.5 psig.

  16. Sizing Methods for Buried Distribution Lines Polyethylene (PE) Piping/Tubing — System Components Figure 8. Polyethylene Tubing Buried Distribution Line for a Two-Stage System

  17. Sizing Methods for Buried Distribution Lines Polyethylene (PE) Piping/Tubing — System Components Figure 9. Anodeless Riser with Stab Connector Figure 10. Cutaway View of PE Inside Coated Steel

  18. Sizing Methods for Buried Distribution Lines Polyethylene (PE) Piping/Tubing — System Components Figure 11. Closer Cutaway View of “Stab” Mechanical Connector Fitting Figure 12. Field Assembled Service Head Adapter Used Here for Transition to 1st Stage Regulator

  19. Sizing Methods for Buried Distribution Lines Polyethylene (PE) Piping/Tubing — System Components Figure 13. Installing Insulated Locater Wire Figure 14. Locater Tape in Trench Above PE

  20. NFPA 54 1999 Sizing Methods for Buried Distribution Lines Polyethylene (PE) Piping/Tubing — To properly size a PE buried distribution line, the length of the line from the outlet of the gas riser to the inlet of the service head adapter must be measured. Add one foot for “snaking” the tubing in the trench. Figure 15. PE Tube Sizing Table 9.33

  21. Sizing Methods for Buried Distribution Lines Polyethylene (PE) Piping/Tubing — Figure 16. Two-Stage Appliance Distribution System Total run is:26 feetTotal system demand is:338,000 Btuh Use: ½” CTS PE

  22. NFPA 54 1999 Sizing Methods for Buried Distribution Lines Copper Tubing— Sizing is done in a similar manner to PE; just use the appropriate sizing chart from NFPA 58 or 54. Figure 17. Copper Tube Sizing Table 9.27 Total run is:26 feetTotal system demand is:338,000 Btuh Use: ½” Type L

  23. Sizing Methods for ½-Pound Distribution Lines The inner surfaces of all piping or tubing resist the flow of propane, thus slowing it down and reducing its pressure as it passes through. This friction loss is commonly known as pressure drop. The term pipe sizing means the selection of the diameter of pipe or tubing which must be used. When sizing pipe, the service person selects the diameter of pipe needed to deliver an hourly Btu load of gas for a specific distance with a loss of pressure of not more than a specified amount, such as 0.5" water column in the 10.5 to 11 inches w.c. sections of a half-pound system.

  24. Sizing Methods for ½-Pound Distribution Lines • According to NFPA 54 the following factors must be considered: • Allowable loss in pressure from point of delivery to equipment burner • Maximum gas demand • Length of piping and number of fittings • Specific gravity of the gas • Diversity factor • Foreseeable future demand

  25. Sizing Methods for ½-Pound Distribution Lines Using Capacity Tables

  26. Sizing Methods for ½-Pound Distribution Lines Using Capacity Tables

  27. Sizing Methods for ½-Pound Distribution Lines Using Capacity Tables

  28. Sizing Methods for ½-Pound Distribution Lines Diversity Factor Diversity factor is a comparison of the maximum probable demand (Btuh) to the maximum possible demand 9Btuh) and is expressed as a fraction or ratio: The use of a diversity factor is not recommended unless the fraction is greater than 1. If it is less than 1, because a diversity factor is an estimate, it does not reflect actual conditions in the piping system, and its use can lead to selection of piping which is not of sufficient size to handle full appliance demand.

  29. Sizing Methods for ½-Pound Distribution Lines Sizing Distribution Lines for Half-Pound Systems Using a 1st & 2nd-Stage Regulator—To determine the sizes of piping or tubing required for the two-stage propane gas installation in Figure 19 use the following method: Figure 19. Two-Stage Propane Gas Installation

  30. Sizing Methods for ½-Pound Distribution Lines

  31. Sizing Methods for ½-Pound Distribution Lines

  32. Sizing 2-PSI System Distribution Lines Distribution lines in 2-PSI systems use smaller diameters in the 2-PSI sections of the system compared to half-pound (11 inches water column) distribution systems. A number of different distribution layouts can be used in 2-PSI systems. Examples using different line materials and line regulator locations are illustrated on the following pages.

  33. Sizing 2-PSI System Distribution Lines Example 1 Figure 20. 2-PSI Single Manifold Distribution System

  34. Sizing 2-PSI System Distribution Lines Example 1: Method for Single Line Regulator Systems with No Branched Runs Off a Single Manifold

  35. Sizing 2-PSI System Distribution Lines Example 1: Method for Single Line Regulator Systems with No Branched Runs Off a Single Manifold

  36. Sizing 2-PSI System Distribution Lines Example 2 Figure 21. 2-PSI Single Manifold with Branched 11” w.c. Line

  37. Sizing 2-PSI System Distribution Lines Example 2: Method for Single Line Regulator Systems with a Branched Run Off the Manifold

  38. Sizing 2-PSI System Distribution Lines Example 2: Method for Single Line Regulator Systems with a Branched Run Off the Manifold

  39. Sizing 2-PSI System Distribution Lines Example 3 Figure 22. 2-PSI Branched Lines & Multiple Manifold Layout

  40. Sizing 2-PSI System Distribution Lines Example 3: Method for Single Line Regulator Systems with a Branched Run Off the Manifold

  41. Sizing 2-PSI System Distribution Lines Example 3: Method for Single Line Regulator Systems with a Branched Run Off the Manifold Although CSST distribution lines were used for Examples 1-3 illustrating 2-PSI systems, remember that steel pipe and copper tubing can be used in 2-PSI systems as well. Some system designs may call for a combination of these materials. Regardless of the materials used in the piping runs, be sure that the correct sizing methods and capacity charts are used when determining the diameter for each type of material used, and its place in the distribution system.

  42. Time to See If You Got the Key Points of This Module… • Complete the Review on pages 25 & 26. • See if you are ready for the Certification Exam by checking off the performance criteria on page 27 & 28.

More Related