iii

CONTENTS

LIST OF TABLES AND FIGURES.................................................. xvii List of Tables ................................................................................. xvii List of Figures .................................................................................. xx

PREFACE.......................................................................................... xxv

ACKNOWLEDGMENTS ............................................................... xxvii

ENGLISH/METRIC CONVERSION FACTORS............................ xxix

INTRODUCTION ................................................................................. 1

The Typical System ........................................................................... 1 The Gas Supply .............................................................................. 1 Pipe Networks ................................................................................ 2 Classification by Pressure Level..................................................... 2 Pressure Regulation ........................................................................ 3

PART I. CAPACITY DESIGN........................................................... 5

CHAPTER 1. SYSTEM LOADS AND DESIGN LOAD ESTIMATION .......................................................... 7

Load Behavior.................................................................................... 7 Demand Profile............................................................................... 7

Residential, Commercial, and Industrial-Firm; Excluding Space Heating ............................................................ 7 Space Heating ............................................................................. 9 Off-peak or Seasonal................................................................... 9 Interruptible................................................................................. 9

Seasonal Load Variations ............................................................... 9 Load Curves.................................................................................. 10

Factors That Determine Demand ..................................................... 12 Weather Factors............................................................................ 12 Customer Factors.......................................................................... 12 Timing Factors.............................................................................. 13

Weather-Load Relationships ............................................................ 13 Degree Days ................................................................................. 14

Applications of Degree Day Index............................................ 16 Wind Effects................................................................................. 18 General Equations......................................................................... 19

Numerical Description of Load Behavior ........................................ 20 Nomenclature ............................................................................... 20 Load Curve ................................................................................... 20 Load Factors ................................................................................. 21 Coincidence and Diversity Factors ............................................... 22 Demand Factor ............................................................................. 24 Ideal Load Characteristics ............................................................ 25 Methods of Obtaining Data on Load Characteristics.................... 26

iv SYSTEM DESIGN

Selection of Customers for Testing............................................27 Group Load Characteristics Studies...........................................27 Need for Continuing Studies......................................................27

Analysis of Results of Demand Meter Studies..............................28 Distribution System Demands ..........................................................28

Customer Demands .......................................................................28 Effects of Conservation .................................................................28

Estimation of Design Loads..............................................................29 The Need for Design Load Estimates............................................29 Design Load Estimation Procedures – General .............................30 Estimating Design Loads for Services ..........................................31 Estimating Design Loads for Mains ..............................................32

Method Based on Connected Load ............................................34 Method Based on Consumption Data ........................................35 Method Based on Average Design Load per Customer..............................................................................38

Design Load Parameters................................................................41 Timing of Peak Demand ............................................................41 Design Weather Conditions .......................................................41 Design Load/Weather Relationship ...........................................42 Design Load Characteristics ......................................................43 Demand Interval ........................................................................44 Leakage Allowance ...................................................................45

Statistical Approach to Design Load Estimation...........................45 Geographical Distribution of Loads..................................................48

Load Gathering by Nodal Areas....................................................49 Load Gathering by Land Area.......................................................49 Computerized Load Gathering ......................................................50

Finder Systems ..........................................................................51 Errors, Pitfalls, and Sources of Inaccuracy................................53

Other Load-Gathering Methods ....................................................55 Validation of Design Load Estimates............................................55

Future Loads .....................................................................................55 Land Growth Patterns....................................................................56 Forecasting ....................................................................................57

Load Records ....................................................................................61

CHAPTER 2. GAS FLOW CALCULATIONS..............................63

Fundamentals of Fluid Flow.............................................................63 Frictional Effects ...........................................................................64 Types of Flow Behavior ................................................................65 Evaluation of Frictional Energy Loss............................................67

The General Flow Equations ............................................................68 Evaluation of Friction/Transmission Factor ..................................69

Moody Diagram.........................................................................70 Transmission Factor for Laminar Flow .....................................73 Transmission Factor for Turbulent Flow ...................................73 Field Measurement ....................................................................74

CONTENTS v

Practical Flow Equations.................................................................. 75 Low Pressure Equations ............................................................... 75 Selection of a Flow Equation........................................................ 77

Equations for Fully Turbulent Flow.......................................... 77 Equations for Partially Turbulent Flow..................................... 78 Determination of Type of Turbulent Flow Behavior ................ 81 The Colebrook-White Equation ................................................ 86

Examples of Flow Calculations........................................................ 87 Manual Flow Calculations............................................................ 88

Resistance Factors..................................................................... 88 Equivalent Length ..................................................................... 91 Equivalent Resistance Factor .................................................... 94 Partial Looping.......................................................................... 96 Capacity Data............................................................................ 98

Modification and Efficiency Factors ............................................ 98 Modifications for Dirty and Rough Pipe .................................... 102 Flow Calculation Applications ................................................... 103

Flow Calculation Aids.................................................................... 104 Flow Computer Programs........................................................... 104 Elevation Corrections ................................................................. 105 High Pressure Systems ............................................................... 105 Low Pressure Systems ................................................................ 105

Pressure Setting Caution ......................................................... 107 Sizing of Individual Mains............................................................. 108

Stub or Dead End Mains............................................................. 108 Undersized Mains in a Network ................................................. 109 Rule-of-Thumb Test of Adequacy.............................................. 111

CHAPTER 3. CAPACITY DESIGN OF SERVICES AND FUEL RUNS ............................................... 113

Services .......................................................................................... 113 Design Load................................................................................ 113

Newly Installed Equipment-Single Residential Unit .............. 113 Newly Installed Equipment-Multiple Dwelling Units ............ 114 Equipment Converted to Gas .................................................. 115

Configuration of the Service....................................................... 116 Route Layout........................................................................... 116 Materials ................................................................................. 116 Fittings and Valves.................................................................. 117

Allowable Pressure Drop............................................................ 118 Flow Calculations ....................................................................... 119

Calculation Aids...................................................................... 120 Fuel Runs ....................................................................................... 123

Sizing and Capacity .................................................................... 124 Allowable Loss in Pressure..................................................... 124 Demand Factor and Maximum Gas Demand.......................... 125 Length of Pipe and Number of Fittings................................... 126 Operating Pressure Limitations............................................... 127

vi SYSTEM DESIGN

Basis of Design............................................................................128 Flow Equations............................................................................128 Design of Vertical Risers ............................................................128

CHAPTER 4. DISTRIBUTION CAPACITY DESIGN PRINCIPLES.........................................................135

Structure of the System Design Problem ........................................135 Constraints...................................................................................136

Operating Limitations ..............................................................136 Delivery Pressure Commitments .............................................136 Source Pressure Available .......................................................137 Pipeline Right-of-Way.............................................................138 Physical Barriers......................................................................138 Safety Considerations ..............................................................138 Reliability of Supply................................................................139 Standardization of Pipe Sizes ..................................................140 Design Policy...........................................................................140

Capacity Design Variables ..........................................................140 Operating Pressure Level.........................................................140 Minimum Allowable Pressure .................................................146 Source Pressure Control...........................................................147 Spacing Between Sources........................................................149 Gradient Pattern .......................................................................152 Gas Velocity ............................................................................154

Reliability and Safety Factors .....................................................154 Looped or Radial System.........................................................154 System Layout and Valve Placement ......................................157 Service Layout .........................................................................158 Regulator Station Design .........................................................159

Development of the Layout for New Systems ................................159 Layout Guidelines .......................................................................159

Constraints ...............................................................................159 Location of Mains....................................................................160 Principles of Design Logic ......................................................160

Layout Procedure ........................................................................163 Performance Criteria ...................................................................164

Reinforcement/Redesign of Existing Systems ................................165 Causes of Need for Redesign/Reinforcement..............................166

Changes in Distribution System Load .....................................166 Deterioration of Existing Pipe Systems ...................................167 Public Works ...........................................................................168

Methods of Reinforcement..........................................................168 Redesign Considerations .............................................................171

Low Pressure Systems .............................................................171 High Pressure Systems ............................................................172 General Considerations............................................................172 Large Loads .............................................................................172 Urban Development.................................................................173

CONTENTS vii

Implementation Planning ........................................................ 173

CHAPTER 5. NETWORK SIMULATION................................. 175

The Importance of Modeling ......................................................... 175 Modeling Design ........................................................................ 176 Modeling in Operations .............................................................. 176 Company-Wide Benefits of Modeling........................................ 176

Engineering Department ......................................................... 176 Operations Department ........................................................... 178 Marketing and Sales Department ............................................ 178 Rate Department ..................................................................... 178 Customer Service Department ................................................ 179 Gas Supply Planning............................................................... 179

Types of Network Simulation Models ........................................... 179 Direct Measurement Model ........................................................ 179 Scale Physical Model.................................................................. 181 Electrical Equivalence ................................................................ 181 Mathematical Models Solved on Digital Computers.................. 182

The Network Modeling Structure .................................................. 182 States of Information .................................................................. 182 Transition From State to State .................................................... 185

The Process: Steady-State Model Formulation and Solution ................................................................................... 186

The Schematic ............................................................................ 186 System Components ................................................................... 187 The System Model...................................................................... 188

The Nodal Approach............................................................... 189 The Loop Approach ................................................................ 191

Modeling Networks With Gas of Various Heating Values ........................................................................... 195 Modeling Networks With Significant Elevation Changes ...................................................................................... 198

The Input: Developing the Database for Network Monitoring ..................................................................................... 198

Describing the Facilities ............................................................. 199 Preparing Customer Load Information ....................................... 199 Assigning Customer Load to the Model ..................................... 200 Derivation of Customer Loads for the Model............................. 201 Supplemental Information Needed for Network Modeling..................................................................................... 201

The Output: Interpretation of Model Results ................................. 202 Typical Result Presentation for Decision-Making...................... 202

Printed Tabular Results ........................................................... 202 Graphical Results .................................................................... 203

Model Checking ......................................................................... 205 Managing the Modeling Function .................................................. 207

Departments Involved in the Modeling Process ......................... 207 Modeling as a Continuous Process ............................................. 208

viii SYSTEM DESIGN

Relationship of the Modeling Function to the Automated Facilities Information System...................................208 Key Ingredients for Successful Network Modeling ....................209

Continual Updating, Checking, and Reporting........................209 Commitment to Network Modeling.........................................209 Sufficient Staffing....................................................................209 Effective Communication of Results .......................................210

Modeling Unsteady Flow in Distribution Systems .........................210 Unsteady Flow as Related to Design...........................................210 Unsteady Flow in Operations Analysis .......................................212

CHAPTER 6. ECONOMICS OF CAPACITY DESIGN .............217

I. Review of Fundamental Concepts...................................................217

Costs ...............................................................................................217 Depreciation ................................................................................218

Straight Line Depreciation.......................................................218 Declining Balance Depreciation ..............................................219

Return on Capital ........................................................................220 Taxes ...........................................................................................223

Income Taxes...........................................................................223 Ad Valorem Taxes...................................................................225 Gross Receipt Tax....................................................................226

Summary of Fixed Costs.................................................................226 Incremental Costs........................................................................226

Time Value of Money.....................................................................227 Time-Line Diagram.....................................................................228 Compound Interest Factors .........................................................229

Net Present Worth....................................................................229 Applications.............................................................................231

Classical Methods of Project Economic Analysis...........................235 Net Present Worth .......................................................................236 Uniform-Annual-Equivalent-Cost Method..................................236 Rate-of-Return Method ...............................................................237

Revenue Requirements Approach to Economic Analysis...............238 Evaluation of the Revenue Requirement for Fixed Costs............238

The Income Tax Factor............................................................239 Example: Automobile Purchase...............................................240 Alternative Formula for Evaluating Capital Costs...................241

The Fixed-Cost-Per-Dollar Factor...............................................242 Decision Criteria for Revenue Requirements..............................244

Feasibility Studies....................................................................244 Comparison of Alternatives .....................................................246

Sensitivity and Breakeven Analysis ............................................247

II. Applications of Economic Analysis...............................................249

Economics of Facility Sizing..........................................................249 Sizing of a Feeder Main ..............................................................249

CONTENTS ix

Break-Even Analysis............................................................... 252 Pipe Sizing Nomograph .......................................................... 254

Sizing of New Distribution System ............................................ 257 Effectiveness Index ................................................................. 257 Other Indices........................................................................... 259 Comparison of Alternatives by Economic Analysis ............... 259

Irreducibles ................................................................................. 259 Reinforcement of Existing Systems............................................ 260

The Benefit Index ................................................................... 261 Regulator Station Economics.................................................. 263 Long-Term Reinforcement Plans............................................ 264

Feasibility Studies for Service to New Areas................................. 264 Example of Economic Analysis for Proposed New Business Extension ............................................................ 266 Year-by-Year Analysis ............................................................... 268 Perspective on Extensions of Service ......................................... 273

PART II. MATERIALS .................................................................. 275

CHAPTER 7. HISTORICAL BACKGROUND.......................... 277

CHAPTER 8. LOAD, STRESS, AND STRAIN ......................... 281

Stress and Strain-General Theory .................................................. 281 Modulus of Elasticity, E ............................................................. 281 Shearing Modulus of Elasticity, G (Modulus of Rigidity).......... 281 Poisson’s Ratio ........................................................................... 282 Yield Point.................................................................................. 282 Proportional Limit ...................................................................... 283 Elastic Limit ............................................................................... 283 Offset Yield Strength.................................................................. 283 Ultimate Tensile Strength ........................................................... 283 Types of Strain ........................................................................... 283

Linear Elastic Strain (Hook’s Law) ........................................ 284 Non-linear Elastic Strain......................................................... 284 Viscoelastic Strain................................................................... 284 Plastic Strain ........................................................................... 284

Stress-Strain Curves ................................................................... 284 Behavior of Material Under Constant Load................................ 285

Tension and Compression Stress and Strain ........................... 285 Shear Stress and Strain............................................................ 286 Torsional Stress and Strain ..................................................... 286 Thermal Stress and Strain ....................................................... 287

Stress in Steel Pipelines ................................................................. 287 Equations for Calculating Hoop Stress....................................... 288

Procedure for Calculating Stress Due to Internal Pressure (SI) ............................................................................ 288 Procedure for Calculating Stress Due to External Loading (SE)............................................................................ 289

External Forces (Loads) Acting on Pipelines ............................. 290

x SYSTEM DESIGN

General Types of External Forces (Loads) ..............................291 External Loading on Buried Pipelines .....................................292

Effects of Earth Loads and Super Loads ..............................293 Interaction of Internal Pressure and External Loading.........294

Calculation of External Loads Acting on Buried Pipelines ......................................................................................294

The General Theory.................................................................294 Methods for Calculating Dead Loads Distributed to the Top of the Pipeline.........................................................296

Standard Vertical Ditch Conditions .....................................297 Negative Projection Embankment Conditions .....................298

Methods for Calculating Live Traffic Loads Distributed to the Top of the Pipeline......................................302

Live Loads Under Rigid Pavement – The Portland cement Association Method ...........................303 Live Loads Under Flexible Pavement – The Spangler Iowa Formula Method....................................307

Stress Research on a Buried Street Pipeline ...................................310 Soil Dead-Load Stresses..............................................................310 Highway and Railroad Crossings ................................................311

Stresses in Steel Gas pipelines Installed on Bridges .......................311 Thermal Stresses .........................................................................312

Effect of Temperature on Pipe Length and Strength ...............313 Maximum Permissible Thermal Stress ....................................314 Design Methods for Thermal Stress ........................................314

Absorption of Stresses..........................................................315 Pipe Loops............................................................................315 Expansion Joints...................................................................315

Support Systems..........................................................................315

CHAPTER 9. METAL MATERIALS IN SYSTEM DESIGN ................................................317

Steel Systems..................................................................................317 Specifications ..............................................................................317

Specifications for Steel Pipe-ASTM API-5L...........................317 Specifications for Steel Tubing-ASTM-539 ............................318 Specifications for Steel Fittings ...............................................318

ANSI-B16.9 .........................................................................318 ANSI-B16.11 .......................................................................318 ANSI-B16.5 .........................................................................318

Fabrication Methods and Characteristics ....................................318 Electrical Fusion Welding .......................................................322 Electric Resistance Welding ....................................................322 Submerged Arc Electric Welding ............................................322 Seamless Pipe ..........................................................................322

Selecting Suitable Pipe................................................................322 Ductility ...................................................................................323 Heat treating ............................................................................324

CONTENTS xi

Impact Resistance ................................................................... 324 Weldability.............................................................................. 324 Pipe Wall Thickness, Operating Pressure, etc......................... 325 Bending Stress ........................................................................ 326 Combined Stress ..................................................................... 327

Mill Inspection............................................................................ 327 Transportation of Pipe ................................................................ 328 Changes in Pipe Direction .......................................................... 328

Mitering .................................................................................. 328 Manufactured Bends ............................................................... 329 Cold or Field Bends ................................................................ 329

Joining ........................................................................................ 329 Welding................................................................................... 330 Compression Couplings .......................................................... 330 Screw Connections.................................................................. 330 Flanged Connections............................................................... 330 Branch Connections ................................................................ 331 Joining Steel to Other Materials.............................................. 332

Cover Requirements ................................................................... 332 Anchors and Supports................................................................. 333 Above Ground Installations........................................................ 334

Flexibility................................................................................ 334 Casing......................................................................................... 335 River Crossings .......................................................................... 335

Water Movement .................................................................... 336 Coatings and Corrosion Control.............................................. 336 Negative Bouyancy ................................................................. 336

Fluid Removal ............................................................................ 337 Corrosion Control ....................................................................... 338

Coating.................................................................................... 338 Corrosion Control Systems ..................................................... 338 HVDC/HVAC......................................................................... 339

Joint Trenching........................................................................... 339 Testing ........................................................................................ 340

Cast Iron Systems........................................................................... 341 Material Characteristics .............................................................. 342 Design of Cast Iron Pipe Systems .............................................. 342 Tapping of Cast Iron Mains........................................................ 343 Joints In Cast Iron Pipe............................................................... 343 Testing Requirements ................................................................. 344 Maintenance ............................................................................... 344

Ductile Iron Systems ...................................................................... 345 Fittings........................................................................................ 345 Design......................................................................................... 345 Joints – General .......................................................................... 346

Mechanical Joints.................................................................... 346 Other Joints ............................................................................. 349

Installation Design Considerations ............................................. 349

xii SYSTEM DESIGN

Laying......................................................................................349 Joint Restraint ..........................................................................349

Test Requirements.......................................................................349 Requirements for Corrosion Control ...........................................350

Copper Systems ..............................................................................351 Materials Dimensions and Testing ..............................................351 Advances of Soft versus Hard Copper Tubing............................353 Copper Applications....................................................................354 Capacity Design ..........................................................................355 Joints ...........................................................................................356 Installation...................................................................................356 Handling......................................................................................358 Corrosion.....................................................................................358

CHAPTER 10. PLASTIC MATERIALS IN SYSTEM DESIGN ................................................361

Overview of Plastic Materials.........................................................361 DOT Regulations.........................................................................362 Strength Measurements ...............................................................362 Basic Dimensional Considerations..............................................365

Pipe ..........................................................................................365 Tubing......................................................................................365

Influences of Temperature...........................................................368 Pipe Strength............................................................................368 Dimensional Change and Resultant Stress...............................368 Example in Determining Thermal Contraction Forces ............371

Statement of Conditions .......................................................372 Statement of the Problem .....................................................372 Values of Variables ..............................................................372 Calculations Assuming Instantaneous Temperature Drop ................................................................373 Calculations for Actual Gradual Temperature Drop ............373

Miscellaneous Stresses ................................................................374 Fittings.........................................................................................374 Joints ...........................................................................................375

Summary of Code Requirements .............................................375 Pullout Forces ..........................................................................377 Force Caused by Temperature Changes ..................................377 Force Caused by Internal Pressure...........................................378 Forces Caused by External Elements.......................................378

Permeability ................................................................................378 Environmental Exposure .............................................................379

Chemical Resistance................................................................379 Weather Resistance..................................................................380

Design Pressure Calculations ......................................................380 Flow of Natural Gas in Plastic Pipe ............................................382

Partially Turbulent Flow (Smooth Pipe Flow) Law.................383 Fully Turbulent Flow (Rough Pipe Flow) Law .......................384

CONTENTS xiii

Resistance to Pullout Forces....................................................... 384 Earth Friction .......................................................................... 384 Earth Interference.................................................................... 385 Fitting Strength versus Pullout Forces .................................... 385 Compression Fittings – Special Considerations...................... 385 Anchoring ............................................................................... 386 Existing Systems ..................................................................... 387

Pipe Behavior Under Earth Loading........................................... 387 External Loads on Pipe .................................................................. 388

Deflection Loads......................................................................... 389 Hydraulic Loads/Negative Pressure............................................ 390 Conditions for Buckling ............................................................. 390

Effect of Pipe Deformation ..................................................... 391 Effect of Soil Support ............................................................. 392

PART III. VALVES AND REGULATORS .................................. 395

CHAPTER 11. VALVE APPLICATIONS IN DISTRIBUTION SYSTEMS................................ 397

Valves at Regulator Stations .......................................................... 397 Valves on Mains ............................................................................ 398 Valves on Service Lines................................................................. 398 General Considerations for Valve Installations.............................. 399

CHAPTER 12. GAS REGULATION AND OVERPRESSURE PROTECTION ...................... 401

Basics of Gas Regulation ............................................................... 401 Principles of Regulator Operation .............................................. 401 Regulator Elements..................................................................... 401

The Sensing Element .............................................................. 403 The Restricting Element.......................................................... 403 The Loading (Responsive) Element........................................ 404

Weight Loading................................................................... 404 Spring Loading .................................................................... 405 Pressure Loading ................................................................. 406

Performance Characteristics ....................................................... 407 Diaphragm Effect.................................................................... 407 Spring Effect ........................................................................... 408 Impingement Effect................................................................. 410 Inlet Pressure Effect ................................................................ 410 Hysteresis Effect ..................................................................... 410 Body Configuration effect ...................................................... 411 Lockup Effect.......................................................................... 412

Proportional Band....................................................................... 412 Control Actions .......................................................................... 413 Regulator Control Methods ........................................................ 414

Self Operated Regulators ........................................................ 414 Self Operated, Velocity Boosting Regulators ......................... 416

xiv SYSTEM DESIGN

Pilot Operated Pressure Loading Regulators ...........................417 Two Path Control (Loading) System....................................418 Unloading System ................................................................419 Instrument Operated Regulators (Control Valves)...............420

Capacity.......................................................................................423 Maximum Capacity .................................................................423 Rated Capacity.........................................................................423 Sizing Methods ........................................................................423

Characteristics of Regulator Valves ............................................425 Regulator Applications ...................................................................425

Appliance Regulators ..................................................................425 Service Regulators.......................................................................426 Industrial Regulators ...................................................................426 Distribution/Transmission System Regulators ............................427 Regulator Noise...........................................................................427 Regulator Freezing ......................................................................428

Basics of Overpressure Protection Methods ...................................428 Relief Valves ...............................................................................428

Liquid Seal Valves...................................................................429 Mechanical Seal Valves...........................................................429

Automatic Shutoff Device...........................................................431 Monitor Regulator .......................................................................431

Nonworking Monitor ...............................................................432 Working Monitor .....................................................................432

Regulation and Overpressure Protection in Commercial and Industrial Applications .............................................................434

Location.......................................................................................434 Design .........................................................................................435 Operation.....................................................................................436 Overpressure Protection ..............................................................437

Control Regulator With a Relief Valve ...................................437 Control Regulator With a Monitor Regulator ..........................438 Control Regulator With Working Monitor Regulator..............438 Control Regulator With a Shutoff Valve .................................439

Accessory Equipment..................................................................439

CHAPTER 13. REGULATOR STATION DESIGN......................441

City Gate Stations ...........................................................................441 District Regulator Stations..............................................................442 Design Criteria................................................................................443 Site Selection ..................................................................................444 Regulator Selection.........................................................................446

Regulator Sizing..........................................................................446 Noise Control ..............................................................................446

Overpressure Protection..................................................................447 Piping and Valves ...........................................................................449 Inlet, Outlet, Bypass, and Control Piping Design ...........................451 Example ..........................................................................................452

CONTENTS xv PART IV. INCIDENT INVESTIGATION.................................... 455

CHAPTER 14. INCIDENT INVESTIGATION ............................ 457

Investigation Fundamentals ........................................................... 457 Types of Pipelines Accidents ......................................................... 458

Material Failure .......................................................................... 458 Human Error............................................................................... 458 Construction Defect/Excavation Damage................................... 459

Management of Accident Investigations........................................ 460 Determining What Constitutes an Accident ............................... 460 Determining Who Is To Investigate............................................ 461 Providing Sufficient Authority To Investigate ........................... 461 Providing a System for Early Notification of Accidents ............ 462 Providing Investigation Training................................................ 462 Providing Specialized Investigative Support .............................. 462 Equipping Investigative Personnel ............................................. 463

Types of Accident Investigations ................................................... 463 One Person Investigations .......................................................... 464 Team Investigations.................................................................... 464 Multi-Disciplinary Investigations............................................... 464

The Investigation............................................................................ 464 Initial action at the Scene............................................................ 464 Principles of Acquiring Accidental Data .................................... 465 Interviewing Witnesses............................................................... 468 Examination of Debris................................................................ 468 General Analysis Data ................................................................ 469

Failure Analysis of Metal Pipe....................................................... 470 Brittle Fracture............................................................................ 470 Ductile Fracture .......................................................................... 472 Major Failure Causes.................................................................. 472

Mechanical Damage................................................................ 472 Welding Defects...................................................................... 473 Corrosion ................................................................................ 474 Stress/Corrosion and Hydrogen .............................................. 474

Samples for Testing .................................................................... 475 Final Report of Findings and Recommendations ........................... 476

APPENDICES, GLOSSARY, NOMENCLATURE AND INDEX ..................................................................................... 479

APPENDIX A. ESTIMATION OF VISCOSITIES OF GAS MIXTURES ........................................... 481

APPENDIX B. DERIVATION OF THE GENERAL FLOW EQUATIONS............................................ 487

APPENDIX C. EXAMPLES OF MANUAL FLOW CALCULATIONS ................................................ 495

xvi SYSTEM DESIGN APPENDIX D. DERIVATION OF EQUATIONS FOR DESIGN OF PARTIALLY PARALLELED OR LOOPED MAINS ...........................................501

APPENDIX E. ADJUSTMENT OF RESISTANCE FACTORS FOR ABNORMALLY ROUGH OR DIRTY PIPE ....................................507

APPENDIX F. DERIVATION OF EQUATIONS FOR LOW PRESSURE ELEVATION CORRECTION......................................................511

APPENDIX G. DERIVATION OF RELATIONSHIP FOR CONCENTRATION OF LOADS ON A STUB MAIN...............................................515

APPENDIX H. BASIS OF RULE-OF-THUMB TEST OF ADEQUACY...................................................517

APPENDIX I. SAMPLE SERVICE CAPACITY TABLES .........519

APPENDIX J. CODES AND STANDARDS................................529

APPENDIX K. DEMONSTRATION THAT THE RATIO OF DESIGN LOAD TO CAPACITY CAN BE EXPRESSED AS A ∆P2 RATIO TERM...............541

APPENDIX L. DEVELOPMENT OF INCOME TAX FACTOR................................................................543

APPENDIX M. DEMONSTRATION THAT THE NUMERATOR OF THE BOYER’S UPSIZING BENEFIT EQUATION IS ∆(∆P2).........................545

APPENDIX N. GRAPHS OF HOOP STRESSES IN PIPE UNDER VARIOUS CIRCUMSTANCES.............547

APPENDIX O. SYSTEM PLANNING TEMPLATE.....................551

APPENDIX P. AKNOWLEDGMENTS........................................567

REFERENCES...................................................................................575

GLOSSARY.......................................................................................587

NOMENCLATURE...........................................................................593

INDEX ...............................................................................................611

xvii

LIST OF TABLES AND FIGURES

LIST OF TABLES

1. Average number of degree days per heating season for American cities ........................................................ 17 2. Examples of constants used in wind correction equation.......... 18 3. Typical load factors for gas customers...................................... 22 4. Examples of demand factors for appliances.............................. 24 5. Typical demand values of gas appliances ................................. 39 6. Information for use in estimating future loads .......................... 58 7. Representative values of peak demand per acre........................ 60 8. Conversion factors for viscosity units....................................... 65 9. Values of flow equation constant, C, for various units ............. 70 10. Formulas and transmission factors for commonly used flow equations................................................................... 76 11. Areas of application of the Mueller, IGT Distribution, and Panhandle A equations for distribution flow calculations ............................................................................... 79 12. Values of the critical Reynolds number and corresponding transmission factor for steel pipe of average wall roughness (k=0.7 mil)...................................... 83 13. Values of the critical Reynolds number and corresponding transmission factor for rougher than normal steel pipe (k=2.0 mil)............................... 83 14. Common flow equation unit length resistance factors .............. 89 15. Unit length resistance factors for Spitzglass high pressure equation .............................................................. 90 16. Unit length resistance factors for Spitzglass low pressure equation................................................................ 90 17. Gas gravity factors .................................................................... 90 18. Dimensions of typical cast iron pipe ......................................... 92 19. Dimensions of steel pipe ........................................................... 92 20. Dimensions of thermoplastic pipe............................................. 93 21 Gas flow rate as a function of pipe diameter and

pressure gradient ....................................................................... 99 22. Suggested efficiency and modification factors for Mueller and IGT Distribution equations ................................. 101 23. Typical demand factors for appliances.................................... 114 24. Equivalent lengths of service fittings ...................................... 117 25. Typical ranges of pressure drop values ................................... 119 26. Trial tabulation of fittings and equivalent lengths................... 121 27. Pipe sizes calculated and specified for Example 3.................. 123 28. Allowable pressure loss for house piping ............................... 124 29. Approximate gas inputs for typical appliances ....................... 125 30. Typical demand factors for appliances.................................... 126

xviii SYSTEM DESIGN 31. Equivalent lengths of standard fittings ....................................126 32. Equivalent lengths of reducing fittings ....................................127 33. Apartment house riser design ..................................................129 34. Results of station spacing study by Consumer’s Power Company ..................................................151 35. Network modeling applications in gas network design and operations ..............................................................177 36. Pipe constants, pipe flows, and node residuals for nodal method......................................................................191 37. Calculation results ...................................................................193 38. Example of DRDB depreciation ..............................................220 39. Example evaluation of return...................................................223 40. Development of compound interest expression .......................229 41. Compound interest factor table................................................232 42. Evaluation of fixed costs-UAE basis for example automobile purchase ................................................................241 43. Basic equations for evaluation of revenue requirements for fixed costs.....................................................242 44. Basic equations for evaluating fixed-cost-per-dollar factors ....................................................243 45. Application of the fixed-cost-per-dollar factor for example automobile purchase ............................................243 46. Evaluation of year-by-year revenue requirements for new business problem ..................................269 47. Deflection and bending moment parameters for circular pipe with load uniformly distributed over top 180 degrees and bottom support distributed over various widths..................................................................290 48. Weights per cubic foot of common backfill materials .............296 49. Values of (Kû) for equation 76 ................................................298 50. Safe working values for the coefficient Cd

to use in Marston’s equation for calculating loads on pipes in trenches ................................................................299

51. AASHO truck loadings............................................................303 52. Load influence coefficient, Cp, for pressure on horizontal subsurface planes for a single load .........................305 53. Load influence coefficient, CT, for pressure above center of pipe of diameter B and length L at depth H below surface .........................................................308 54. Standard dimensions and weights of steel pipe .......................319 55. Pipe functions by diameters (Schedule 40)..............................321 56. Values of S and R for cast iron pipe design.............................343 57. Standard wall thickness values for ductile iron pipe................347 58. Standard specifications for copper pipe...................................351 59. Copper tubing dimensions .......................................................352 60. Chemical requirements for types K and L copper tubing........................................................................352 61. Standard lengths of copper tubing ...........................................353

LIST OF TABLES xix 62. Rated internal working pressure for copper tubing and solder joints ........................................................... 355 63. Corrosion of copper and steel materials in various soils......... 359 64. Values of LTHS and HDB at three temperatures.................... 363 65. Typical values of HDB for widely used PE materials at various design temperatures ................................ 364 66. HDBs for other plastic pipes at 73°F (23°C)........................... 364 67. Wall thickness and standard dimension ratio for thermoplastic pipe ............................................................. 366 68. Maximum allowable operating pressure (psi) of SDR- dimensioned thermoplastic piping systems for given long-term hydrostatic strengths ..................................... 367 69. Plastic tubing diameters, wall thickness, tolerances................ 367 70. Typical properties of PE 2406 pipe......................................... 369 71. Typical apparent modulus of elasticity of PE 2406 pipe......... 369 72. Wall thickness and tolerances for plastic pipe (ASTM A2513)....................................................................... 370 73. Selected operating limitations for plastic pipe operated at 100 psi maximum in class 3 and class 4 locations................................................................ 380 74. Typical maximum flow rates experienced in 60 psi steel or plastic natural gas distribution systems ...................... 382 75. Allowable deflection of polyethylene pipe ............................. 389 76. Critical buckling pressures...................................................... 391 77. Comparison of overpressure protection devices ..................... 450

xx SYSTEM DESIGN

LIST OF FIGURES

1. Diagram of typical gas distribution system .................................1 2. City gate station...........................................................................2 3. Estimated daily gas loads for a year ............................................8 4. Daily load curves for cooking customers ..................................11 5. Effect of temperature on space heating daily load curves for a residential customer ...............................................11 6. Load curves of two types of commercial customers..................11 7. Scatter of average daily gas consumption per customer when plotted against average daily temperature........................14 8. Load nomenclature ....................................................................20 9. Demand factor terms .................................................................23 10. Example of nodal area ...............................................................33 11. Objective of design load estimation...........................................33 12. Extreme low temperature demand factor trends ........................43 13. General risk factor plot for design load .....................................46 14. Relation of coldest day risk factor and design load ...................47 15. Example of nodal area ...............................................................49 16. Chart of customer location code by quarter section in townships...................................................................50 17. Load grouping by regulator feed area using quarter sections ..........................................................................51 18. Street intersection showing node numbers and finders..............52 19. Area load growth pattern ...........................................................56 20. Symbols used in load plotting....................................................62 21. Velocity profile of fluid in laminar flow through pipe ..............64 22. Flow patterns for laminar and turbulent flow ............................65 23. Partially developed turbulence ..................................................66 24. Fully developed turbulence........................................................67 25. Moody diagram of friction factor ..............................................71 26. Plot of transmission factor vs. Reynolds number ......................73 27. Comparison of Mueller, IGT Distribution, and Panhandle A equations transmission factors with smooth pipe flow law ................................................................79 28. Comparison of Spitzglass and Weymouth equations transmission factors with smooth pipe flow law........................80 29. Plot of critical Reynolds number as a function of nominal pipe diameter and internal wall roughness ..................82 30. Pipe sections in series ................................................................94 31. Pipe sections in parallel .............................................................95 32. Cast iron pipe layouts ................................................................95 33. Effect of pipe diameter on capacity .........................................100 34. Diagram of pressure vs. distance along a low pressure gas main laid up-hill ..................................................106 35. Network diagram with stub mains ...........................................108 36. Gas flow rates in a stub main...................................................108

LIST OF FIGURES xxi 37. Flow rates and main lengths for two uniform flow configurations ................................................................. 110 38. Relation between flow rate and pressure loss for a main operated at high pressure ....................................... 111 39. Pipe footages for service described in Example 3................... 122 40. Separation of service described in Example 3 ........................ 122 41. Economics of pressure for small town systems ...................... 142 42. Comparison of relative system costs-60 psig base.................. 143 43. General cost/pressure curve .................................................... 145 44. Cost objectives for new developments in distribution system technology................................................................... 145 45. Idealized piping layout based on Doherty’s principles ........... 150 46. Ideal piping layout developed by Gary ................................... 150 47. Idealized square-mile service area .......................................... 153 48. Typical square-mile service area............................................. 153 49. Fully gridded distribution system ........................................... 155 50. Radial distribution system....................................................... 156 51. Double main system................................................................ 158 52. Design terminal pressure vs. inlet pressure to maintain constant percent overload capacity .......................... 162 53. Portable recording pressure gage ............................................ 166 54. Reinforcement of low pressure system ................................... 168 55. System design capacity vs. inlet pressure with a constant percent overload capacity ......................................... 170 56. Use of tie-in to increase capacity of a distribution system.................................................................. 170 57. Pressure drop vs. temperature ................................................. 180 58. Gas network modeling flow chart........................................... 183 59. Schematic for model formulation ........................................... 184 60. Loop formulation schematic ................................................... 192 61. Variable gravity and Btu content description of variables.............................................................................. 196 62. Definition of volumetric mixing for modeling networks with variable gravity and Btu content ..................... 197 63. Schematic of a simple cross or crossover ............................... 197 64. Printer plot of New York City high pressure facility network ....................................................................... 204 65. High resolution plot delineation of pressures by line style............................................................................. 205 66. Schematic of example for transient analysis ........................... 211 67. 24-hour load profile ................................................................ 211 68. Pressure at node B for three alternatives................................. 212 69. Lost gas calculation schematic before break........................... 213 70. Lost gas calculation schematic after break.............................. 213 71. Flow leaving the system through the break............................. 214 72. Recorded and predicted pressures at node LOAD .................. 215 73. Annual fixed charges vs. time................................................. 227 74. Effect of time value money on future worth of a dollar.......... 228

xxii SYSTEM DESIGN 75. Time-line diagram ...................................................................228 76. Effect of timing on the present worth of a dollar.....................230 77. Diagram of intent.....................................................................246 78. Example of results of sensitivity analysis................................247 79. Information for use in the sample economic analysis associated with selecting the size of a feeder main..................250 80. General plot of installed cost of facility over time ..................251 81. Pipe sizing profitability nomograph ........................................255 82. Economics of district regulator vs. distribution main investments .....................................................................265 83. Decision structure for discretionary projects ...........................270 84. Form for guiding economic decision making – Side 1: Capital Requisition ......................................................271 85. Form for guiding economic decision making – Side 2: Feasibility Estimate .....................................................272 86. Stress-strain curves for different materials ..............................282 87. Behavior of materials under constant load ..............................285 88. Pipe deflection under external loads and internal pressure.......................................................................293 89. Typical condition of bedding and loading on pipe in trenches...................................................................294 90. Free body diagram for ditch pipe.............................................295 91. Installation conditions for earth load calculations ...................297 92. Cn calculation coefficients for negative projection condition.................................................................301 93. Distributed loading – rigid pavements.....................................304 94. Point loading – flexible pavements..........................................307 95. Stress rupture time plots for polyethylene pipe materials, showing influence of temperature ...........................363 96. Average monthly ground temperature (°F), Wilmington, Delaware.............................................................372 97. Stress and force curves calculated for gradual temperature changes, based on Figure 94................................374 98. Gas flow as a function of pipe diameter for cast iron, steel, and plastic pipe ...............................................383 99. Percent pipe deflection as a function of load, trench width, and trench depth.................................................388 100. Reduction factor fo as a function of pipe diameter in an ovaled pipe.......................................................392 101. Support factor fs as a function of SDR.....................................392 102. Pilot operated regulator ...........................................................402 103. Self operated regulator.............................................................402 104. Typical self operating regulator...............................................403 105. Pressure profile across valve ...................................................404 106. Weight and lever loaded regulator...........................................405 107. Spring loaded (appliance) regulator.........................................406 108. Constant pressure loading regulator ........................................406

LIST OF FIGURES xxiii 109. Self operated, constant pressure/spring loaded regulator with downstream bleed............................................ 407 110. Diaphragm effective diameter................................................. 408 111. Regulator performance showing diaphragm effect ................. 409 112. Regulator performance showing spring effect ........................ 409 113. Regulator performance showing inlet pressure effect for single inner valves upstream of orifice.............................. 410 114. Hysteresis effect...................................................................... 411 115. Regulator performance showing body effect .......................... 411 116. High and low recovery valves................................................. 412 117. Regulator shutoff characteristics............................................. 413 118. Rollout type diaphragm........................................................... 415 119. Lever type service regulator.................................................... 415 120. Regulator with seal diaphragm ............................................... 416 121. Regulator with double valves.................................................. 416 122. Performance curve showing effect of velocity boosting..................................................................... 416 123. Variable pressure loading system-bleed to line....................... 418 124. Unloading pilot system on a diaphragm-sleeve regulator.................................................................................. 419 125. Simple instrument control system........................................... 421 126. Set point adjustment................................................................ 421 127. Proportional band adjustment ................................................. 422 128. Reset device ............................................................................ 423 129. Valve characteristics ............................................................... 425 130. Typical oil seal relief valve..................................................... 429 131. Deadweight loaded relief valve............................................... 430 132. Spring loaded relief valve ....................................................... 430 133. Service regulator with internal relief ...................................... 431 134. Automatic shutoff device........................................................ 431 135. Automatic shutoff valve installation ....................................... 432 136. Monitor regulator installation ................................................. 433 137. Working monitor installation .................................................. 433 138. Control regulator with a relief valve ....................................... 437 139. Control regulator with a monitor regulator ............................. 438 140. Control regulator with a working monitor regulator .................................................................... 438 141. Control regulator with a shutoff valve .................................... 439 142. Typical regulator installations................................................. 445 143. Typical underground regulator station.................................... 448 144. Typical above-ground regulator station .................................. 448 145. Aerial view of accident site showing explosive readings taken after accident................................................... 467 146. Relationship of events and causal factors ............................... 471 147. Chevrons pointing right toward origin and opposite the fracture propagation............................................ 472 148. Fracture along gouge............................................................... 473

xxiv SYSTEM DESIGN 149. Girth-weld failure – 5x magnification .....................................473 150. Rough polished cross section of cast iron pipe........................474 151. Fracture resulting from embrittlement .....................................475

Volume IIIDISTRIBUTIONThe American Gas Association

Notices, Disclaimers and Copyright04.Preface.pdfEditor, 2004

05.acknowl.pdf2004OFFICERSDonald M. FieldJames F. WunderlinGeorge JongelingAGA STAFFLori S. TraweekLarry T. IngelsAli QuraishiKimberly DenbowEngineering Services DirectorEngineering Services DirectorEngineering Services DirectorAndrew LuNneka AssingDirector Operations SafetyEngineering Services Manager

08.Chap1-Loads.pdfFACTORS THAT DETERMINE DEMANDExample 2

TABLE 2TABLE 3TABLE 4Information for Use in Estimating Future LoadsInformation for Use in Estimating Future LoadsPeak Gas Demand

09.Chap 2-FlowCalcs.pdfGerald G. WilsonPanhandle A Equations for Distribution Flow Calculations

SPL, 1000sRange of ApplicabilityFor Rougher Than Normal Steel Pipe [k=2.0 mil (0.05 mm)]10Critical ReEXAMPLES OF FLOW CALCULATIONS

G=0.65Resistance Factor**TABLE 17Gas Gravity FactorsTABLE 19

Minimum Wall Thickness [in. (mm)]TABLE 21

10.Chap3-CapaDesign.pdfTABLE 23Demand FactorFittings

TABLE 25TABLE 26Fittings

TABLE 27TABLE 28House Piping

Demand FactorTABLE 31TABLE 33

Riser Design Bb,cSectionRunTSO**EllCock

TotalSectionkBtuRunTSO**ROT†

Section

ThermRunCockTotal

11.Chap4-DesignPrincp.pdfGerald G. Wilson and Samuel I. HymanSYSTEM DESIGN PROBLEMCONSTRAINTSDelivery Pressure CommitmentsSource Pressures AvailablePipeline Right-of-WaySafety ConsiderationsReliability of SupplyStandardization of Pipe SizesDesign PolicyCAPACITY DESIGN VARIABLESOperating Pressure LevelSource Pressure ControlSpacing Between SourcesRELIABILITY AND SAFETY FACTORSLooped or Radial SystemSystem Layout and Valve PlacementRegulator Station DesignDEVELOPMENT OF THE LAYOUT

Location of MainsPrinciples of Design LogicLAYOUT PROCEDURE

OF EXISTING SYSTEMSChanges in Distribution System LoadDeterioration of the Existing Pipe SystemsPublic WorksMETHODS OF REINFORCEMENTREDESIGN CONSIDERATIONSLow pressure SystemsGeneral ConsiderationsLarge LoadsUrban DevelopmentImplementation Planning

12.Chap5-NetworkSim.pdfDesignOperationsPipe Constants, Pipe Flows, andNode SubscriptUNSTEADY FLOW AS RELATED TO DESIGN

13.Chap6-EconCapDesign.pdfGerald G. WilsonD = \(P – L\)/n = \(10 000 – 1 000\)/9 = $1 �

TABLE 38P = 9 ($1 000) + $1 000 = $10 000Example Evaluation of Return

DepreciationWhen federal tax is not deductible in computing state tax-SUMMARY OF FIXED COSTS

TIME-LINE DIAGRAM

TABLE 40F = P (1 + i)n = 2 000(1.10)25 = $21 670�where:A = end of year annuity

P/FF/PA/PA/FP/AF/AP/FF/PA/PA/FP/AF/AP/FF/PA/PA/FP/AF/APROJECT ECONOMIC ANALYSIS

Cost ComponentTABLE 43UAE/$Comparison of AlternativesExample$5 000 = x (UAEFC/$) + $2 000$5 000 = 0.292 7x + $2 000 ( x = $10 249

UAERRA = UAERRB

Net Earnings

16.Chap8-LoadStressStrain.pdfYIELD POINTPROPORTIONAL LIMIT

Tension and Compression Stress and StrainCrossing ConditionsKzKbEffects of Earth Loads and Super Loads

TABLE 48Kind of BackfillExample 1

TABLE 49Step III.Calculate the stress on the pipeline

Example 2Step III. Calculate the stress on the pipeline

TABLE 51Step II. Determine the surface load factor, k, by use of Equation 79Step V. Calculate the stress on the pipeline

L/2HStep V.Calculate total dead and live load per linear foot, W*Step VI.Calculate the stress on the pipeline

THERMAL STRESSES

17.Chap9-MetalMatls.pdfStandardExtra StrongDoubleExtra StrongStandardExtra StrongDouble Extra StrongTABLE 55WeldabilityMiteringFlanged ConnectionsJOINT TRENCHING

Type of PipeSMAINTENANCE

Wall Thickness [in. (mm)] for Depth of Cover [ft (m)] Indicated at Top of Each Column**Wall Thickness [in. (mm)] for Depth of Cover [ft (m)] Indicated at Top of Each Column**TABLE 59

LLTABLE 60TABLE 63

18.Chap 10-PlasticMatls.pdfTABLE 64TABLE 66Piping Material Designation

Table 69, which is based on CTS dimensions, lists diameters, wall thickness, and tolerances for plastic tubing of various nominal sizes.TABLE 67Minimum Wall Thickness [in. (mm)]

TABLE 69ToleranceTemperature

TABLE 72Calculations for Actual Gradual Temperature DropFLOW OF NATURAL GAS IN PLASTIC PIPEEarth Interference

Joint TypeJoint StrengthPipe StrengthCompression Fittings - Special Consideration

TABLE 75Effect of Soil Support

20.Chap11-ValveApplic.pdfSamuel I. Hyman

21.Chap12-Reg&OverPress.pdfDiaphragm EffectSelf Operated, Velocity Boosting RegulatorsTwo Path Control (Loading) SystemNonworking Monitor

22.Chap13-RegStaDesign.pdfTABLE 77INLET, OUTLET, BYPASS, ANDCONTROL PIPING DESIGN

26.AppendixA-EstofViscos.pdfTABLE A-1TABLE A-2

29.AppendixD-LoopEquations.pdfCAPACITY OF LOOPED SYSTEM

30.AppendixE-ResistFactorsDirtyPipe.pdfSOLUTION

33.AppendixH-AdequacyTest.pdfTABLE H-1

34.Appendix I-EquivLengthTables.pdfAppendix IRichard C. Gaulin, Anthony Messina

Low, Low-Medium, and Intermediate PressuresTotalExisting or New service (by Service Tap Size)ActualLength (ft)a1 in.1¼ in.b1½ in.2 in.3 in.4 in.6 in.8 in.( 302504506401 1502 9705 90011 00020 00031 to 601903605209602 7005 35010 50019 00061 to 1001503054408402 4204 8509 80018 000101 to 1501302653857402 1704 3509 20017 000151 to 2001102303406901 9704 0008 80016 000Medium PressureTotalNew Service (by Service Tap Size)Actual1 in1½ in.2 in.3 in.(2 in.)4 in.\(3¼ in.\)6 in.\(5¼ in.\)( 307603 2505 83013 00027 00056 00031 to 606702 8005 22012 00025 00052 50061 to 1005902 4304 65011 00023 00050 000101 to 1505202 1204 1009 80021 00046 500151 to 2004701 9003 7008 90019 00044 000Medium PressureTotalExisting Service (by Service Tap Size)Actual1 in.1½ in.2 in.( 305901 0701 1801 33031 to 605501 0201 1601 32061 to 1005009801 1201 310101 to 1504559301 0901 290151 to 2004258901 0601 280High PressureTotalActual1 in.1½ in.2 in.3 in.(2 in.)4 in.\(3¼ in.\)( 3031 to 6061 to 100101 to 150151 to 200High PressureTotalActual1 in.1½ in.2 in.( 3031 to 6061 to 100101 to 150151 to 200TABLE I-3aPlastic Service off Steel MainPlastic Service off Cast Iron MainPlastic Service off Plastic Main

TABLE I-3bPlastic Service off Steel MainPlastic Service off Cast Iron MainPlastic Service off Plastic Main

TABLE I-3cPlastic Service off Steel MainPlastic Service off Cast Iron MainPlastic Service off Plastic Main

Table I-4FittingValvesWelsbach 1\(¾Welsbach 1(1Service valveCurb valveElbows45(90(TeesFlow thru sideFlow, straight thruConnections at service regulator2 ft of pipe & two 90( elbowsConnections to main & riser teeFull size main tapping¼ in. orifice at main½ in. orifice at main? in. orifice at main1 in. valve tee1 in. orifice at main1¼ in. orifice at main1½ in. orifice at main2 in. in. orifice at main2¼ in. orifice at main2½ in. orifice at main3 in. orifice at main3¼ in. orifice at main5¼ in. orifice at main7¼ in. orifice at mainPipe1 ft of ½ in. pipe¾ in. pipe1 in. pipe1¼ in. pipe1½ in. pipe2 in. pipe2½ in. pipe3 in. pipe4 in. pipe6 in. pipe8 in. pipe

FittingMedium Pressure Mains [2 psig to 15 psig (14 kPa to 103 kPa)]

36.AppendixK-PressureRatioTerms.pdfGerald G. Wilson

38.AppendixM-BoyersUpsizing.pdfGerald G. Wilson

45.Index.pdfDHNRSUVWY